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VOL. XXXII
no. 4
'kP
PSYCHOLOGICAL REVIEW PUBLICATIONS
WHOLE NO. 146
19^3
Psychological Monographs
EDITED BY
JAM'ES ROWLAND ANGELL, Yale University
HOWARD C. WARREN, Princeton University ( Review )
JOHN B. WATSON, New York (/. of Exp. Psychol.)
SHEPHERD I. FRANZ, Govt. Hosp. for Insane ( Bulletin ) and
MADISON BENTLEY, University of Illinois (Index)
STUDIES FROM THE PSYCHOLOGICAL LABORATORY
OF THE UNIVERSITY OF CHICAGO
Certain Factors in the Development
of a New Spatial Co-ordination
BY
* v
MARGARET WOOSTER C
PSYCHOLOGICAL REVIEW COMPANY
PRINCETON, N.J.
Agents: G. E. STECHERT & CO., London (2 Star Yard, Carey St., W. C.)
Paris (16 rue de Cond6)
ACKNOWLEDGMENTS
To the subjects who so cheerfully and patiently went through
with the often protracted series of sittings, I am deeply grateful.
Dean James R. Angell I wish to thank for generous interest in
this investigation and for inspiring instruction. To Dr. Harvey
A. Carr, under whose direction the investigation was carried out,
I am grateful for minutely painstaking and searching criticism,
and especially for the freedom which he prescribed for me in
working out my problem. Those who have done research work
under Dr. Carr’s direction will understand the statement that it
has been one of the greatest privileges in my experience to feel
the inspiration of such a scientific attitude as his.
CONTENTS
PAGE
I. INTRODUCTION— STATEMENT OF PROBLEM i
II. APPARATUS AND METHOD . 4
III. DESCRIPTION OF EXPERIMENTAL SERIES
AND RESULTS . 12
STANDARD SERIES . 1 3
1. Effect of Knowledge of Experimental Conditions
a. Experiments with knowledge
b. Experiments without knowledge
2. Effect of Position of Body, Head, and Eyes
a. Experiments with undistorted vision
b. Experiments with distorted vision
VISUAL LOCALIZATION OF SOUNDING OBJECTS . 47
1. First Group, Using Electric Buzzer
2. Second Group, Using Electric Bell
a. With vibration visible
b. With vibration invisible
LOCALIZATION WITH TOUCH . 58
1. Passive, as Result of Chance Success
2. Active, as Check at Each Localization
LOCALIZATION WITH VISUAL PERCEPTION OF DISTORTION 63
LOCALIZATION WITH TACTUAL-KINAESTHETIC CLUES
FROM LEFT ARM . 67
IV. RETENTION OF THE NEW CO-ORDINATION. . 73
V. SPECIFICITY OF READJUSTMENT . 75
VI. RELATION OF READJUSTMENT TO DEFINITE
LOCALIZING ACTIVITY . 89
VII. SUMMARY AND CONCLUSIONS . 91
I
INTRODUCTION
The purpose of this investigation was to determine exper¬
imentally the relative influence of various sensory modes of re¬
action, as sight, touch, and hearing, in the building up of a new
space habit. This particular habit was developed by the subjects
in the process of learning to localize correctly objects seen through
prismatic glasses which distorted the visual field.
The perception of space is, to a greater or less extent, the
product of individual experience. The adult is able to adjust him¬
self spatially to the outer world only by virtue of the possession
of a system of complex habits of reaction. These habits have been
slowly and painfully acquired, most of them in infancy. But
the process of acquisition as it occurs in infancy is forgotten, and
later changes in space reactions come so gradually that the details
of the adjustment are not noticed. The adult learns to find a
new keyhole in the dark in much the same way that the child
learns to pick up his rattle. Hence it is easy to overlook the fact
that every move we make depends for its nicety and accuracy
upon the unified functioning of an exceedingly intricate reaction
system — a system in the building up of which countless simple
reactions have played a part.
It would be of great importance for psychological theory to
determine the mechanisms underlying the development of this
complex system of adjustments. Does the development take place
on a purely sensory-motor level, or is it influenced by ideational
factors ? Is actual movement in space essential, or could a passive
subject gain effective perception of a spatial situation? Do all
normal individuals develop spatial habits in the same way, or
are there individual differences in the matter?
The chief problem discussed in the theoretical literature on
the genesis of psychological space so far has concerned the
relative importance of various sensory factors. Taste and smell
i
2
MARGARET WOOSTER
and the organic and cutaneous modes of activity other than con¬
tact, are by common consent held to be of negligible importance
in this connection, in spite of the contention of James that all
sensations possess original spatial quality. The status of hearing
is in dispute. In general, psychologists are inclined to assign it
little if any importance as a spatial sense. Contact, however, has
been considered to be highly important as a factor in space per¬
ception, this attitude being correlative with the popular notion
that touching an object is the final test of its real existence. To
others vision has seemed the spatial sense preeminent. Vision
and touch, it is held by some, are the only senses that “possess
real spatial character,” and other senses, such as kinaesthesis,
become important in space experience only by virtue of their
connection with these.
While an enormous quantity of experimental work has been
produced bearing on the spatial aspects of the various senses
taken in isolation, almost nothing has been done by way of in¬
vestigating experimentally the relative influence of the various
sensory factors as they cooperate in the development of complex
types of spatial reaction. Speculation has been supplemented, it
is true, by observations on the behavior of young children and
of animals; on the reported experiences of congenitally blind
persons restored to sight; and on certain cases of alleged ab¬
normalities in the space reactions of adult individuals. But not
only has none of the data so adduced as evidence been gathered
and presented in a scientifically systematic way, but it does not
seem likely that in such fields of observation enough experimental
control can ever be introduced to insure validity for the con¬
clusions drawn.
It is possible, however, to demonstrate conclusively, by ex¬
perimental procedure, certain central facts about the manner in
which spatial coordinations may develop. If we cannot get at
the actual initial processes in the development of the complex
world of space for any individual, we can at least investigate
experimentally the building up of certain spatial coordinations,
by observing what happens when an individual readjusts himself
to space relations that have been artificially disturbed. The ex-
THE DEVELOPMENT OF A NEW SPATIAL CO-ORDINATION 3
perience of people who have gradually become used to a new
pair of glasses which alters in any noticeable way the field of
vision, offers an illustration of the fact that it is possible though
practical experience to , readjust one’s ordinary coordinations
in such a way as to harmonize again disturbed spatial relations.
Strangely enough it was not until comparatively recent years
that the idea of investigating the development of spatial organ¬
ization by producing and then overcoming an artificial disorgan¬
ization, was conceived and carried out. In 1897 Professor George
M. Stratton published his celebrated paper on “Vision without
Inversion.” The immediate purpose of the experiments reported
in that article was to prove that inversion of the retinal image
is not a necessary condition of upright vision. They furnished
also, however, a striking demonstration of the predominantly
empirical character of spatial organization. Incidentally they
threw some light on our particular problem of the relative efficacy
of various concrete factors in adjustment.
Stratton, it will be recalled, in his main experiment adopted
the plan of wearing glasses constructed from lenses which com¬
pletely reversed the retinal image, and hence directions in the
field of vision, so that objects formerly appearing to the right
now appeared to the left, and objects formerly in the upper part
of the field of vision now looked to be in the lower part. In other
words, on first assuming the glasses the entire visual scene ap¬
peared to be upside down. Stratton wore these glasses continously
for eight days, except during hours for sleeping, when he was
carefully blindfolded. He went about his ordinary activities some¬
what as usual. He found that not only was he able gradually to
make effective practical adjustment to the changed visual situa¬
tion, but that at the same time the new arrangement came to seem
more and more natural to him, until at the end of eight days
things no longer appeared to be upside down. A new visual sys¬
tem had even in that short time been more or less completely
organized, and harmonized with sense impressions from differ¬
ent fields to such an extent that his space world was again unitary.
This experiment of Stratton’s demonstrated first that the in¬
version of the retinal image is not a necessary condition of normal
4
MARGARET WOOSTER
vision, the fact which he originally set out to prove. It showed,
second, that it is possible in the give and take of ordinary ex¬
perience to build up an entirely new spatial organization in which
various sensory factors come to be associated together in new
ways.
In addition to establishing these general facts, Stratton made
valuable observations on the role played by various factors con¬
tributing to the process of readjustment. It was his main purpose,
however, to establish the general fact that harmonious read¬
justment can occur, rather than to study the specific factors con¬
cerned in the process. He made no effort, therefore, during the
course of the experiment systematically to investigate the form¬
ation of any one coordination, but merely noted down, as the ex¬
periment progressed, those observations which seemed to him
pertinent. These observations constitute a valuable contribution
to the factual study of the more general aspects of space per¬
ception, but additional data of a specific and quantitative nature
are needed as a basis for more detailed conclusions. In fact it
would take the combined results of many individuals to warrant
the drawing of such general conclusions.
It is the aim of the present work, then, to contribute something
toward the experimental investigation of those factors in the
development of space perception which Stratton treated only in¬
cidentally. We know now, through his experiment, that disturbed
space relations can be effectively reorganized in experience. The
next step is to determine how such a reorganization is effected' —
what factors cooperate, what their relative influence is, and what
their mode of functioning.
II
APPARATUS AND METHOD
Stratton’s method, while admirable for his purpose, is far too
complex for ours, and would involve too much fatigue and in¬
convenience to be employed with any considerable number of
subjects. The essential nature of the process in question would be
the same were the observers to be subject to the disturbed con-
THE DEVELOPMENT OF A NEW SPATIAL CO-ORDINATION 5
ditions for only a short time each day, instead of continuously.
If under such circumstances reorganization could be secured at
all, it would permit of definite experimental control and would
yield results just as significant for the general theory of space
perception as would those obtained in more complex situations,
in which exact control would be almost impossible.
We finally determined to use, instead of Stratton’s 180 degree
reversing lenses, a pair of prismatic glasses which produced an
angular deviation of the visual field of about 21 degrees. These
the subjects wore for 20 minutes each day, while working at the
simple task of localizing, by reaching movements, objects ar¬
ranged in definite positions. We found that under these circum¬
stances there was a gradual and progressive tendency, more
or less completely fulfilled according to experimental conditions,
to overcome the wide initial visual distortion and to localize the
objects more and more accurately. We then planned a series
of experiments with the object of determining first, what are
the sensory or other factors concerned in this particular process
of readjustment; and second, what is the relative efficacy of
the different factors involved.
The glasses used in our experiment consist of two 40 degree
optical prisms producing an angular deviation of about 21 de¬
grees. These were mounted in a light aluminum frame in such a
way that they can be easily adjusted back and forth; or turned
in any one of the four directions — right, left, up, or down. The
prism used for the left eye consists of two 20 degree prisms com¬
bined, and produces a deviation slightly greater than the prism
for the right eye, but not great enough to cause any trouble in
combining the images for the two eyes. Throughout the experi¬
ments we were thus able to work with binocular vision, in which
respect our conditions are superior to those of Stratton, who
relied on monocular vision.
Careful measures were taken to insure that no light should
enter the eyes of our subjects except that which came through the
prisms. The light frame in which the prisms are mounted, is so
shaped as to fit closely over the nose. To the upper and lower
6
MARGARET WOOSTER
sides are glued fitted pieces of black cloth-covered felt about a
fourth of an inch thick, so shaped as to extend back and rest
against the forehead and cheeks. To the ends of the frame are
attached double flaps of black cloth which extend back toward
the ears. The glasses were kept in place by an adjustable rubber
band extending from the ends of the frame around the back of
the subject’s head. When they were put on, a piece of cotton was
slipped under the lower part of the frame, over the cheeks and
nose, in such a way as to fill up any space that might remain.
Thus only light that came through the prisms was admitted to
the eve.
j
At first subjects usually felt somewhat disturbed, on account
of the strangeness of the prismatic effect, and the unusual limita¬
tion of the visual field by the frame of the glasses. But this feel¬
ing soon wore off, and after two or three sittings they reported
feeling quite natural and at ease. The glasses are fairly light and
not uncomfortable. It is easy to obtain a relatively clear single
image of any object by turning the head in the proper direction.
While wearing these glasses the subject was set to work at a
task offering favorable conditions for the formation of a new
spatial coordination. He was seated at a table facing a row of
objects which he was to localize by reaching out with his right
arm and right index finger. (See Plate I.) These objects, small
electric buzzers (C), are suspended at about the level of the
subject’s eyes from a horizontal iron rod (R) elevated 35 cm.
above the top of the table. The rod is held in place by three
wooden uprights fastened to a board at the back of the table
which joins two other boards at the ends (G, G) to form a box¬
like upper extension of the table, open in front.
Now with the prisms adjusted to cause a deviation to the right,
a buzzer which was really directly in front of the subject ap¬
peared to be about 25 cm. to his right, and in pointing it out he
touched a point 25 cm. farther to the right than the buzzer actual¬
ly was, there being no incentive to correct to the left. In order that
the subject might not see his arm when reaching for the buzzers,
and thus be tempted to correct the obvious error, a wooden
cover was provided for the box-like extension, attached at the
THE DEVELOPMENT OF A NEW SPATIAL CO-ORDINATION 7
ends to the top of the end boards (G, G). The subject, seated in
the chair with base at I, thus looked over the cover at the objects
(C) but localized them by reaching out his arm under the
cover. When leaning back in the chair between trials, the sub¬
ject was prevented from seeing his body by the frame of the
glasses. Hence at no time while wearing the glasses was any part
of the subject’s body visible to him.
In certain of the series it was necessary that the position of
the subject’s finger be observable by the experimenter, seated
back of the apparatus, while not by the subject himself. There¬
fore just beneath the buzzers there is a narrow slit, between the
cover and the back of the extension, through which the ex¬
perimenter could look down and note the position of the sub-
8
MARGARET WOOSTER
ject’s finger. It was necessary also that this slit be widened at
times in order that the subject might at the end of his reaching
movement see his finger and thus note his error; or in order that
the buzzer might be lowered down through the slit in such a
position that the upper half would be visible to the subject, and
the lower half, although beneath the cover and invisible, could
be touched by the subject as he reached out. To provide for the
three different widths of the slit thus necessary, the back part of
the cover is made adjustable, or capable of being moved from
back to front and vice versa, to widen or narrow the slit. It is
desirable that this movable part of the cover have a thin edge and
a smooth under surface furnishing no tactual clues of position,
and so it is made of a strip of glass about 18 cm. wide, with the
upper surface painted black. This strip (B) is set in a sliding
wooden frame which can be pushed part way back under the front
or wooden part of the cover (A). The distances by which this
adjustable strip in its frame shall be moved to front or back
is regulated by means of brass stops at the ends of the frame.
In this way the strip can easily be set for any one of the three
different widths of the slit desired.
The position of the buzzers along the rod and their height
above the table can be easily changed. The detail diagram (Plate
II) shows how this can be done. Each buzzer is clamped to the
lower end of a long screw. To this screw is attached a brass clamp
through which the buzzer can be adjusted up and down. The
clamp fits over the iron rod and can be securely attached to it
at any position by means of a small thumbscrew at the back.
The buzzer can thus be raised (after loosening the thumb screw
and the small nut) by lifting the clamp off the rod, and setting it
toward the bottom of the screw. It can be lowered by setting the
clamp toward the top of the screw. The clamp can be put in the
same position on the rod, or in another position, and screwed in
place as before. In the figure one buzzer is shown raised and an¬
other lowered half way through the slit. In actual practice all the
buzzers are at the same height in the same experiment.
The buzzers are connected with two dry cell batteries kept in
a box attached to the back of the apparatus. They are operated
THE DEVELOPMENT OF A NEW SPATIAL CO-ORDINATION 9
Plate II
by means of a row of push buttons arranged near the battery box.
The light flexible wires from the buzzers hang inconspicuously
down over the rod at the back. Also at the back of the table, to
the experimenter’s right, is a shelf for her use in recording data,
and to her left a small shelf for extra buzzers. None of these parts
of the apparatus are in view of the subject.
In most of the experimental series it was necessary that the
subject should not be able to perceive the extent and direction of
his error by noting the position of the experimenter’s head when
she bent over to get the record. To prevent this, two different
methods were used. At first the subject was merely asked to close
10
MARGARET WOOSTER
his eyes as soon as the localization was made. This proving un¬
satisfactory, a black curtain (D, Plate I) was arranged to shut
off the view of the buzzers after each localization. It operates be¬
tween two vertical iron rods (H, H) by means of a system of
rings, screw pulleys (E, E), and cords, which enable the experi¬
menter to manipulate the curtain easily and quickly by the use of
one hand behind the apparatus.
The chair in which the subject was seated is a small armless
swivel chair of adjustable height, easily rotated. It was kept
in the same position throughout the sittings, 15 cm. in front of the
line connecting the front legs of the table, the center of it 12 cm.
to the left of the mid-point of that line. The experimenter sat
on a high office stool back of the apparatus and just opposite
the subject. (Base of stool shown at J.)
A few minor points will complete the description of the ap¬
paratus. The iron rod is covered with rubber tubing to prevent
jarring and modification of the sound of the buzzers. Just back
of the board which forms the back of the extension, is painted a
centimeter scale (reading from right to left from the subject’s
point of view) on which the position of the subject’s finger at
any localization can be read off by the experimenter. A vertical
black line painted on the front face of each buzzer makes it more
easily localizable. The whole apparatus with the exception of the
buzzers is painted a dull black, the lines of the scale being marked
in white.
The dimensions of the chief parts of the apparatus not already
given are as follows: top, 60.5 cm. by 121 cm.; height, 78 cm.;
height of cover above table, 27.5 cm. ; diameters of buzzers,
4.5 cm.
The general order of procedure in the experiments was about
as follows. On the first day the subject was given a preliminary
test for accuracy of normal localization of the buzzers by hand
movement, without the glasses. On the second day he wore the
glasses, and was instructed to localize the buzzers in the same man¬
ner as at the first sitting, as they appeared to him, disregarding the
fact of distortion. Under these conditions it was found that the
subjects, influenced consciously or unconsciously by certain sen-
THE DEVELOPMENT OF A NEW SPATIAL CO-ORDINATION u
sory or other factors, showed in succeeding sittings a tendency
to approach closer and closer to the actual or normal standard
of localization. For instance in the first day’s sitting with dis¬
torted vision subject R. reacted on the average 18 cm. to the
right of the actual position of a buzzer; in the second day’s
sitting the average distance from the true position was only 16.5
cm. ; in the third, only 14.5 cm., the fourth 12 cm., and so on.
The original aim of the experiments was to continue the sit¬
tings for each subject either until he had completely ‘‘overcome
the effects of the distortion”, as happened in many cases; or
until he had reached the limit of improvement. Since it was im¬
possible for many of the subjects to continue with the sittings
until such a limit had been reached, the latter requirement had to
be given up. But all the subjects whose results are considered in
the group comparisons either “overcame the effects of the dis¬
tortion” in less than 10 sittings, or continued until 10 sittings
with distorted vision had been taken.
The time of day for the sittings was kept constant for each
subject as nearly as possible, and was very rarely changed. In
general each subject took one sitting a day, six days a week,
although occasionally it was necessary to omit two days out of
the seven. Each sitting lasted exactly 20 minutes. In that time
20 localizations were made, five for each of four different posi¬
tions of the buzzers along the scale, the interval between the
“localizations” or trials being 60 seconds throughout all the ex¬
periments. Such a long interval was made necessary by the cir¬
cumstance that in certain of the series adjustments of the ap¬
paratus which required that much time had to be made in the
interval.
During the interval conversation between the subject and ex¬
perimenter was permitted and in fact encouraged, first that the
subject might feel at ease and natural, and second that he might
get the habit of making his localizations in an unstudied and
automatic manner just as he would reach out for an object under
the conditions of everyday life. The effort was made to get each
subject to give himself up freely to the conditions of the ex¬
periment. The directions called for a disregard of the fact of
12
MARGARET WOOSTER
distortion, and required the subject to react, although carefully,
without self-consciousness or critical analysis of the nature of
the localizing movement or of the possible error. Introspective
comments were not asked for until after the final sitting, but re¬
marks made spontaneously were carefully noted during the series ;
and if a peculiar tendency in the results developed at any time a
question was put by the experimenter relative to the subject’s
attitude or understanding of the directions. Unusual bodily con¬
ditions — of extreme fatigue, excitement, etc. — were reported and
recorded by the experimenter.
In all 72 subjects were used in the main experiments — five
being Instructors in the Department of Psychology of the Uni¬
versity of Chicago, 40 graduate students in the University (most
of these in the Department of Psychology) and 27 upperclassmen
taking a course in psychology. The writer conducted all of the
experiments in person, except that at two different times of emer¬
gency fellow graduate students, Miss Dorritt Stumberg and Miss
Katherine Ludgate, very kindly helped out by each giving three
or four sittings to two subjects already started in a series. The
writer herself acted as subject in all the experimental series pos¬
sible, while others acting as experimenter, and with conditions as
nearly like those for the other subjects as could be arranged. In
this way she took series A-i, B-i, C-2, and D.
The experiments here discussed extended over a period of
about 12 months.
Ill
DESCRIPTION OF EXPERIMENTAL SERIES AND
RESULTS
There has been much disagreement concerning the relative ef¬
ficacy of the various modes of sensory reaction in the develop¬
ment of space habits. Particularly has this been the case with re¬
spect to sight and touch (including kinaesthesis). Whether or
not hearing is a “spatial sense,” or may contribute anything to
the development of an organized system of spatial reactions, is
also a much disputed question. Taste and smell are almost
THE DEVELOPMENT OF A NEW SPATIAL CO-ORDINATION 13
universally held to be of negligible significance in this respect.
Our investigation, therefore, has to do with the relative efficacy
of hearing, sight, and touch, as factors contributing to the form¬
ation of the new spatial coordination developing under the con¬
ditions of our experiment.
There were five main series of experiments. The first (A)
was given as a standard series for purposes of comparison with
later series. Records were secured from a group of subjects
showing their manner of localization of the buzzers from day
to day, with distorted vision, but without the sensory clues
the influence of which was later to be tested. For this series
the slit at the back of the cover was so narrowed that the sub¬
ject could not see his finger after reacting, nor touch the buzzer.
The buzzer was not sounded as the signal for reaction, but merely
pointed out by finger movement.
In the second series (B), designed to test the efficacy of sound,
conditions were exactly as in the first except that the buzzer was
sounding. In the third series (C), to test the efficacy of touch,
the buzzer was lowered half way down through the slit so that
when a correct localization occurred there would be contact of
the finger with the buzzer. In the fourth series (D), to test the
efficacy of sight of the localizing finger, the slit was widened so
that the finger tip could be seen after the localization had been
made, and the buzzer was raised high enough to prevent contact.
In the fifth series (E), designed to test the influence of taetual-
kinaesthetic sensations from the left arm, no buzzers were used.
The subject extended his left arm over the cover, bending the
index finger down through the slit, and localized this finger as
the buzzer was localized in preceding series, by a reaching move¬
ment of the right arm under the cover.
STANDARD SERIES
1. Effect of Knowledge of Experimental Conditions
a. Experiments With Knowledge
For the standard series, four buzzers were set along the rod
at the positions 53, 66, 79, and 92 on the scale. The total length
14
MARGARET WOOSTER
of the scale being 20 cm., this means that they were set toward the
left end, in such a position that they were directly in front of
the subject. Distorted, they appeared shifted about 25 cm. farther
to his right. On the first day the subject was given 10 trials for
normal accuracy of localization of the buzzers, without the
glasses. At the second sitting he began the series with distorted
vision. The experimenter first instructed the subject as to the
proper position of the chair, and then placed his right arm in
front of him more or less parallel to the edge of the table. She
told him that at the signal “Ready” he was to assume this posi¬
tion, but not to feel that the position was to be rigidly defined —
that the only object was to get a uniformly free sweep of the
arm. The subject was told also that he would work in ignorance of
the purpose of the experiment, and was cautioned not to talk to
other subjects who had finished, about that purpose. Then he was
given the following instructions, typewritten, and asked to study
them carefully:
“When I point out one of these four buzzers by placing my
finger on it, localize it as in preceding series without the glasses
by a direct movement of the right index finger to the point just
below the midpoint of the buzzer indicated. The glasses will give
a distorted view of the buzzers, but pay no attention to this fact
in making your localizations, simply taking pains to localize the
buzzer as accurately as possible as it appears to you. You will
have no means of judging the accuracy of your localizations,
so pay no attention to the possible nature of errors, but reach
out directly to the buzzer, in a natural and automatic manner,
concentrating your attention on the sight of the buzzer. In making
the localizing movement, move your head and body freely, as you
choose.
“When you have touched the board, close your eyes and keep
your finger in place until I say ‘All right.’ Then relax in your
chair and open your eyes if' you wish. When I say ‘Ready’ assume
your former position with your arm in place ready to react as
before. There will be one trial every 60 seconds, and the stimuli
will be given in irregular order. You may converse on indifferent
topics between trials, but at the signal “Ready”, which will be
THE DEVELOPMENT OF A NEW SPATIAL CO-ORDINATION 15
given two seconds before the stimulus, all conversation will cease.”
After the subject had read these instructions the glasses were
put on him by the experimenter and he swung around in the chair,
facing the buzzers. The point is to be emphasized that the sub¬
ject, in making his localizations, had no direct sensory means of
judging their accuracy. The buzzers were not sounding. The slit
was so narrowed that the subject could not see his finger when
he had made a localization. In order that he might not gain
knowledge concerning the direction and extent of his error
through noticing the position of the experimenter’s head when
she bent over to take the record, the instructions are explicit
that the subject shall close his eyes as soon as he has touched the
board, and not open them until she says “All right” which means
that the position of the finger has been noted and that the ex¬
perimenter has assumed her usual position again. Great care was
taken in regard to this point.
While the subject was not told what was the direction of the
deviation, in most cases he found it out during the first sitting,
being familiar with the normal appearance of the apparatus and
knowing how the prisms were set in the glasses. But there were
no clues to enable him to realize the extent of his error from
day to day. The fact that there was no such realization, is proved
by the comments of the subjects, who confessed themselves in
the dark and frequently made absurd estimations of the amount of
their errors. But this group did work, it must be noted, with
some knowledge of the experimental conditions.
The results of this first series with distorted vision are sur¬
prising. They indicate that there is from the first localization, a
progressive tendency on the part of most subjects gradually to
approach the actual position of the buzzer. In general the rate
of readjustment is slow. Of the initial linear deviation, which
in this group averages for the four buzzers 21.1 cm., only 40.5
per cent on the average was recovered in the first 10 days. How¬
ever for the six subjects in the group who were kept at the task
until the limit of improvement was apparently reached (until
at least five sittings in succession showed no improvement) the
total percentage of readjustment amounted to 59 per cent over
i6
MARGARET WOOSTER
the initial deviation. This means that in spite of the fact that
these subjects had no sensory clues as to the actual position of
the buzzers, they still “readjusted” to the new visual situation,
to the extent that they learned to localize the buzzers at a point
about 60 per cent nearer their actual position than they had local¬
ized them at the beginning of the series. In other words we have
an ascending curve instead of the straight line that might have
been expected.
A glance at Figure I, showing graphically the results of sub¬
ject H. R. K., which are typical for the first group of experi¬
ments, will make the situation clear. The numbers on the ordinate
refer to positions on the scale in centimeters, and those on the
abscissa to successive days’ sittings. The four straight lines at
53, 66, 79, and 92 represent the actual positions of the 4 buzzers.
Buzzer number 1 (53) is to the subject’s right; buzzer number 4
(92) to his left as he sits at the apparatus. The curves which
approach the lines show the progress of the subject from day
to day, each point on a curve representing the average of the
five trials for that buzzer taken on that day. The line and curve
for buzzers 92 (4) and 66 (2) are dotted, while those for 79
(3) and 53 (1) are unbroken.
In seeking for a method of treatment of the results which should
be suitable for all the series of experiments in our investigation, we
finally decided on the following plan. The measure of the amount
of readjustment effected in any case is the distance in centimeters
still “unrecovered” when the subject has reached his highest point
of readjustment. In the case of any subject, then, this distance will
be obtained for each buzzer by substracting the average of the
five localizations made at the highest point of readjustment, from
the average of the five trials for normal visual accuracy made for
the same buzzer. This will give the number of centimeters that
would have to be “recovered” before the subject would again
attain his normal accuracy in localizing the buzzer. Such a linear
distance yet remaining to be “recovered” we will call arbitrarily
in our discussion of results, “the remainder.” For example sub¬
ject H. R. K., beginning with a linear deviation of about 25 cm.
for buzzer number 1, had reached as her high point of readjust-
THE DEVELOPMENT OF A NEW SPATIAL CO-ORDINATION 17
Fig I. Readjustment of Subject H. R. K. Standard Series
ment for that position, on the 19th day’s sitting, the average
position of 44.5 cm. Her average normal localization for buzzer
1 ls 55-5 cm- Her remainder for buzzer 1, then, for the whole
period of the series, is 55.5 cm. minus 44.5 cm., or n cm.
In addition to thus measuring the amount of readjustment by
the remainder, or remaining distance from the normal standard
of accuracy, it is also convenient at times to use as a measure the
per cent of the linear deviation which has already been recovered.
Such a measure is, however, far less significant for comparative
discussion than the remainder, for the reason that it is based on
i8
MARGARET WOOSTER
the initial linear deviation, which varies greatly among indivi¬
duals.
While theoretically the glasses should produce a standard ob¬
jective linear deviation which is the same for all individuals,
practically, under the conditions of our experiment, they do not.
This is because in the first place the position of the head is not
constant, and the linear deviation varies somewhat with every
change in the distance from the buzzer to the eye, and in the
angle formed by this line with the scale at the back of the ap¬
paratus along which the linear deviation is measured. It was not
possible to keep these factors constant by fixing the head posi¬
tion, because among the series is one involving auditory localiza¬
tion, for which free head movement is essential; and general
conditions had to be constant throughout the experimental series.
A second reason for individual variation in linear deviation
may be found in the variability of the angle of incidence or the
angle at which the rays of light from the buzzer strike the prisms.
According as the buzzer is viewed through the large or the small
end of the prisms, there is a difference of several centimeters in
linear deviation. As a matter of fact with the direct forward
fixation which was naturally maintained in localizing the buzzers
the change due to variation in angle of incidence would be so
slight as to be practically negligible. It must be reckoned with,
however, as a factor tending to produce a slight amount of varia¬
tion from individual to individual as well as within the results
of any one subject.
Thus it is impossible to determine a standard general linear
deviation upon which to base per cents of readjustment for all
subjects. It might seem practicable to base the per cents of read¬
justments for an individual on his own initial linear deviation.
But it is not possible closely to determine even this individual
deviation. Several trials would be needed for a reliable determina¬
tion. Readjustment, however, begins after the very first trial,
and indeed in some series even prior to it. Again, the head posi¬
tion even of one individual, may change somewhat from trial to
trial for the same buzzer.
It is clear, then, that for purposes of group comparison the
THE DEVELOPMENT OF A NEW SPATIAL CO-ORDINATION 19
remainder, rather than the per cent of readjustment, is the more
reliable measure of progress. It will be helpful, however, to deal
with per cents in treating individual results, and in broad general
discussions.
To find the per cent of readjustment for any individual we
must find the total distance between the initial localization with
the glasses and the place of normal localization, and determine
what per cent of that distance has been recovered at the highest
point of readjustment. In the first two series, A and B, the five
localizations of a buzzer in the first sitting are about the same,
and so to find the initial deviation for individuals in those series
we will subtract the average of the first five trials for a given
buzzer, from the average of the 10 trials for normal accuracy
of localization of the same buzzer.
In series C, D, and E, however, readjustment is so rapid that
the average for the first five trials for a position would already
represent an advance of as much as several centimeters over the
initial localization for that position. Hence in these later groups
we are compelled to find the initial deviation for a given posi¬
tion by subtracting the first trial only from the average normal
localization. This will mean greater variability in linear devia¬
tions, since one trial is not a sufficient measure of accuracy. Here
too there will be considerable variability in the amount of initial
deviation for the four different positions, owing to the fact that
readjustment is already in progress after the first localization
among these four. For the last three series, then (C, D, and E),
since the per cent of readjustment based on initial deviation will
be particularly variable and thus unreliable for comparative pur¬
poses, the usual basis of comparative discussion will be the re¬
mainder.
Individual and group results for series A-i-a are given in
Figures I and II and in Table I (p. 20). Nine subjects in all
served in this group. This includes the writer whose peculiar
knowledge of the situation makes her results not strictly com¬
parable with the others, and one subject who was forced early
to discontinue the sittings. This leaves seven whose results are
considered in computing group averages.
20
MARGARET WOOSTER
TABLE I
Standard Series
Showing results for Group A-ia ( with knowledge ) and Group A-i-b
( without knowledge )
Sub- No. Visual Acc. Av.*l.d. Av. Ay. Per centPer cent
jects of Sit- - ist 5 Rem. Rem. Readj. Readj.
tings 53 66 79 92 trials 10 da. Total I0
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THE DEVELOPMENT OF A NEW SPATIAL CO-ORDINATION 39
we noted as characteristic of the curves for the first two groups;
but it could not account for the continued and steady progress of
the curves which indicate a per cent of readjustment as high as
79. It would have been possible to devise an extra series to isolate
the factors of muscular strain, due to long arm reach, and of
head-body disparity; but owing to limited time this was not
done. The two factors together did not prove, in fact, to have
much influence, as will be brought out later.
b. Experiments With Distorted Vision.
In the second group of experiments to test the effect of the
bodily attitude and muscular strain situations, our aim was to see
if we could obtain a curve in the opposite direction, or at least
one approximating a straight line, by shifting the buzzers far
to the left as suggested, so that the localization of the buzzers as
distorted would involve an unusual reach and a turning of the
head to the left. Certainly if the first adjustment were independent
of the prismatic glasses, such an adjustment could be produced in
this way in a direction contrary to that which theoretically would
take place to “overcome” the prismatic deviation.
In the new test, A-2-b, for three of the subjects all conditions
were exactly as in A-i-b (Experiments without knowledge), ex¬
cept that the three buzzers were set far to the subject’s left in
such a position that when distorted, the one farthest to the right
would appear to be, even for the maximum linear deviation,
slightly to the left of the normal perpendicular to the central
body axis, while the localization of the one farthest to the right
would involve a long reach accompanied by unusual muscular
strain. The positions on the scale for the three buzzers were 91,
101, and 1 17.
In Table III, p. 41, is a summary of the numerical results for
this group. Fig. V, p. 40 shows typical curves, those of E. H.
E. and R.
Four subjects took this test, all continuing for at least 10
sittings. Not one of them showed a tendency to readjust to the
right. Three on the contrary showed a very marked readjustment
to the left, working thus against an increasing sense of muscular
MARGARET WOOSTER
40
Fig. V. Standard series. Distorted.
THE DEVELOPMENT OF A NEW SPATIAL CO-ORDINATION 41
strain, which they mentioned. The one who did not readjust re¬
mained more or less on a level for a few days, then fell to a
level only very slightly higher than for the first sitting.
Of the three subjects who showed marked improvement, none
were aware of the extent of the deviation and were even uncertain
of its direction at times. E. H. E., on seeing her results, felt
greatly surprised that she had been making a progressive change ;
and that the “feeling in her arms” did not inform her of this.
She thought she had been hitting in the same positions all the
time.
H. A. C. was very familiar with all the conditions of the ex¬
periment, and a highly trained observer. At the fifth sitting he
reported that all the time he felt as if he were going too far to
the left, and when his finger got there, he felt that if he moved
it a little to the right, it would be more correct. At the ninth
sitting he said, “Don’t know whether Eve improved or not —
if I were going to guess, would say probably I hadn’t — largely
guess work.”
In Table III is a summary of the results for the four subjects
for a 10 day period.
TABLE III
Readjustment with Buzzers at the Left, Distorted Vision.
Subject
Average
Remainder
Per Cent
Readjustment
Average
Initial L.D.
P. R.
5-0
68
15-5
F. 0. D.
2.1
85
10.0
E. H. E.
.8
99
10.2
H. A. C.
10.0
22
9.8
Average
4-5
68
12.3
On first glance at these figures it would seem that the read¬
justment even on the average was so much more rapid than that
in the standard series as to require the supposition either of
another causative factor or of an unusual coincidence in the
matter of individual variability. But consideration of the effect
of the changed position of the buzzers explains this apparent
discrepancy. The amount of linear deviation varies regularly
with the size of the angle included between the line of fixation
42
MARGARET WOOSTER
and the line of projection (the scale), according to the formula
c sin B
b — - - where b is the linear deviation (L. D.) and B the
sin C
angle of deviation of the prisms. Now if the other angle, A,
formed by the line of fixation for a buzzer and the scale is small,
then the L. D. is correspondingly smaller. Now all the A’s in this
situation are less than right angles, while in the other groups all
were greater. This means that the L. D. will be much smaller,
and in fact we do find the average L. D. here, 12.3 cm., to be
less than two thirds of the average L. D. for the first series A-
i-a and A-i-b, which is 19 cm.
Now with a smaller L. D. the same absolute amount of read¬
justment would not only correspond to a disproportionately
larger per cent of total readjustment, but the remainder would
also1 be smaller. For example, suppose the absolute amount re¬
covered by two subjects in each group to be 5 cm., and the L. D.
to be 20 cm. Now for the subject in A-i-a this would represent
25 per cent of readjustment and a remainder of 15 cm., while
for a subject recovering the same distance in group A-2-b, the
per cent of readjustment would be 50 and the remainder only
5 cm. Hence we see that the two sets of results are not directly
comparable, and may assume that in reality the average L. D. of
these subjects would be about the same as in the first group, were
conditions the same; and that the amount of readjustment would
not be greatly different.
Now under the conditions of this series with distorted vision
the head must be either in line with the body or turned farther
to the left. Hence the fact that marked readjustment to the left
nevertheless occurs proves conclusively that although the head-
body discrepancy may have been, and presumably was, slightly
effective in causing the original readjustment, a much more ef¬
fective cause must have been at the basis of the readjustment for
most subjects. The same statement holds for the hypothesis that
the original readjustment may have been due to a gradual re¬
laxation in attention to localization with a consequent following
of the direction of least bodily effort, for in this case readjust¬
ment took place in the direction of increasing bodily strain.
THE DEVELOPMENT OF A NEW SPATIAL CO-ORDINATION 43
It becomes necessary again to search for other possible factors.
We have a gradual change in method of localizing, marked and
steadily increasing for most subjects, without any known basis,
sensory or ideational, for such a change. Now every reaction must
have a conditioning stimulus, immediate or remote. What is the
stimulus here?
After much pondering a possible solution of this problem came
to mind, suggested by the line of reasoning followed in discussing
the head-body position. Briefly the theory is as follows. The
position of the eyes in the head is such that they are turned to the
right of the head axis, just as the head is to the right with
reference to the central axis of the body. It is the habitual tend¬
ency to react to the front as determined by head position rather
than eye position which conditions the tendency to readjust to
the left. The other factors of head-body position and of tend¬
ency to equalize strain may enter in as subordinate influences,
but the main incentive to readjustment is the eye-head situation.
Let us see what the exact implications of this hypothesis are.
It may be said that there are for the individual three distinct
meanings of the word “front” — one with reference to the central
axis of the body, one with reference to the head axis, and one with
reference to the line of vision when the fovea is stimulated by the
fixated object. Now it is reasonable to suppose the foveal front
to be less dominating in the habitual reaction systems of the in¬
dividual than the head front. In the first place the eye is much
more active and varied in the direction of its fixation than the
head. In the second place it is necessary to recognize the exist¬
ence in this experiment of two different sensory aspects, visual
and kinaesthetic, of the concept front, whereas normally the
bodily reactions to the kinaesthetic and the visual situations are
objectively the same. That is, the subject now sees the buzzer
in front to be in one place, but with his head and body he feels
that “front” is in another direction, farther to the left. If the
subject wearing the glasses saw his head and body at the same
time he saw the buzzer, it is possible that this old kinaesthetic
set would be harmonized with the new visual situation and the
localizations would be consistently in one place. But the glasses
44
MARGARET WOOSTER
are so constructed, and the conditions of the experiment are such,
that the subject does not see any part of his head or body. Hence
it is natural that the old or normal kinaesthetic reaction tend¬
encies should be very strong when the subject is working under
the injunction to reach out “in front”, and that there should be
a marked tendency to point in the direction of the head-axis
rather than the eye-axis which is for the time being farther to the
right.
At first when the subject might be expected to give particular
attention to the localization of the novel visual object, he would
respond to it by precise movements in harmony with the new
visual situation. But since the attention of the subject gradually
lessens and the process becomes automatic, it is quite natural
that he should by degrees fall back into the more usual habit
of reacting in harmony with the normal “feel” of the head. This
would explain the gradual nature of the readjustment to the left.
The superiority of this explanation over the other hypotheses
advanced lies in the fact that unlike them it works in the series
with distorted vision just described. It is not hard to show that
no matter what the direction of the line of vision, the eye will
still be turned in its socket farther to the right than in normal
fixation. In normal foveal fixation of an object the line of vision
and the head-axis coincide. When the prism is placed before the
eye of the subject, the object is deflected to the right, and in order
to adjust properly to it the head is turned to the right together
with the attached prism. But this turning of the prism again alters
the angle of incidence of the ray of light from the object, with
the result that it is refracted to the periphery of the retina. Hence
and in order to obtain clear foveal fixation, the eye must turn
still farther in the socket. Otherwise the object would be seen
in peripheral vision, an unnatural situation for an object attended
to. The amount of sequential turning of the eye is sufficient to
make the eye-head discrepancy clearly apparent to the observer
as the subject is in the act of localizing a buzzer.
This optical situation can be stated in a definite mathematical
formula by the physicist, but it is sufficient for our purposes to
recognize the mere fact that for every turn of the head there
THE DEVELOPMENT OF A NEW SPATIAL CO-ORDINATION 45
will be a sequential turning of the eye still farther to the right,
at an angle of noticeable extent, though less than the angle
between the head-axis and the main body-axis. Taking into ac¬
count the existence of this discrepancy, and the highly complex
and delicate way in which the performance of any act is in¬
fluenced by the total sensory situation at the moment, it is easy
to understand the readjustment to the left as a perfectly natural
adaptation to the changed sensory situation induced by the prisms.
It is clear now why no marked readjustment occurs when the
prisms are not worn.
The progressive character of the readjustment can be explained
on this hypothesis in two ways. In the first place the subject
might at first concentrate his attention on the visual stimulus
and the correctness of his reaction to it, and hence react with
reference to the “foveal front.” Later, though the foveal fixation
is still maintained, he might naturally relax his vigilance and
fall comfortably into the more habitual manner of reacting with
reference to the “head front”.
Or, in the second place, he might continue consistently to re¬
act with respect to the foveal axis, but that axis itself might
change, in, let us say, the following way. At first the subject, anx¬
ious to localize the object correctly, takes pains to get a clear foveal
fixation. But this involves some muscular strain since the eye is
turned farther in the socket than normally. And he can attend
to the object visually through peripheral as well as foveal fixation.
What is more natural than that, as the process of reacting be¬
comes increasingly automatic, the eye should relax its tension and
gradually assume a compromise position nearer its normal posi¬
tion in the head ; or even continue until it has reached the normal
position? This means that the eye-axis would slowly approach
the head-axis, and finally, in some cases, coincide with it. As-
uming that in this case the reaction of the subject is always
with reference to the foveal front, the above assumption would
account nicely for the progressive character of the readjustment
to the left. Individual differences in readjustment would be due
to physiological differences in susceptibility to muscular strain.
It seems probable that readjustment due to this prism-induced
46
MARGARET WOOSTER
eye-head discrepancy may be effected in both these ways, some
subjects reacting in one way, some in another. That the general
fact of the eye-head discrepancy is very significant for the pro¬
cess of readjustment appears highly probable. The chief merit
of the hypothesis is that it will hold for the case in which read¬
justment to the left took place even in the direction of increasing
bodily strain and in the face of a slight turning of the head to
the left as compared with the body. For no matter what the
direction of the object with reference to the body, we know that
the eyes will always be turned in their sockets to the right of their
normal position.
There are, however, some difficulties which indicate that this
hypothesis is very likely only a partial explanation, and not suf¬
ficient to explain all the facts we have discovered in the course
of our experiments. How, for instance, on this basis, can we ac¬
count for the fact that in the case of R. D. in the Auditory
Series readjustment occurred rapidly and surely, and then halted
and remained on a level for ten days at exactly the point of ob¬
jectively correct localization? R. D’s localizations here were,
moreover, far more accurate reactions than she had made to
sound alone. According to the present theory why should the
readjustment stop at any particular point, much less at this point?
Unfortunately in none of the other cases in the first and second
series where complete or nearly complete readjustment seemed
to occur, were the sittings continued long enough to see if the
process would go on indefinitely.
This hypothesis did not occur to the writer until after the
conclusion of the experimental work for the investigation, when
it was too late to check it up experimentally. In a later sup¬
plementary investigation, however, the writer hopes to carry out
the experimentation necessary to clear up the matter.
It may be said parenthetically at this point that in the later
series in which complete readjustment occurred, due to known
sensory clues, the readjustment should on this theory go on,
though at a slower rate, to a point some distance to the left of
the actual position of the objects. There is no reason to assume
that this would not have occurred, yet here again positive evi-
THE DEVELOPMENT OF A NEW SPATIAL CO-ORDINATION 47
dence is needed, since the sittings were stopped when the actual
position of the buzzers was reached.
VISUAL LOCALIZATION OF SOUNDING OBJECTS
1. First Group, Using Electric Buzzer
The second main series of experiments was designed to test
the efficacy of sound as a factor in the formation of the new
visual coordination. For the first group of experiments in this
series one of the electric buzzers was used as the object to be
localized. In this case it was sounded at each trial. One buzzer was
used instead of four as in the preceding series, and shifted be¬
tween trials to different ones of the four positions 53, 66, 79,
and 92, according to a predetermined order. The object of using
the one buzzer instead of four was first, to keep the quality of
the sound as nearly constant as possible. It was found practically
impossible to get four buzzers of the kind employed that were
of the same pitch and timbre, or to equalize those we had. The
second object was to make possible an easy identification of the
sounding buzzer. If but one of four was sounding, it would be
a hard task for a subject wearing the prisms to tell at once which
one it was.
Before starting the main series of trials with distorted vision,
a preliminary series was given to test the accuracy of the sub¬
ject in normal auditory localization of the buzzer in the four
positions. The subject, after being instructed how to reach out for
the buzzer, was blindfolded and seated at the apparatus. At the
signal “Ready,” followed by the sound, he was to decide carefully
at about what point along the rod the buzzer was, moving his
head and body freely as desired, and taking all the time needed,
the sound meanwhile continuing. When he had decided, he was to
reach out and make the localization. When he touched the board
the sound stopped. In order that the subject might not know or
guess from what position the sound was to be expected, (1)
he was not told that only four positions were used; (2) the trials
were given in regular order but the order was frequently changed;
and (3) the buzzer was moved noiselessly between trials, con-
48
MARGARET WOOSTER
versation going on in the meanwhile. The interval between trials
was one minute. Fifty trials were taken for each of the four
different positions of the buzzer, from 20 to 30 trials being
given in a day’s sitting.
When the preliminary series had been completed the subject
began the series with distorted vision, with procedure exactly
as in the first main series, A-i, except that the one buzzer, shifted
between trials, was used instead of four, and that the experi¬
menter gave the signal for reacting by sounding the buzzer in¬
stead of by placing her finger on it. The typewritten instructions
were exactly as in the standard series, A-i, except for the change
in describing the signal for reaction. Nothing was said about
localizing the sound. The object was thus to see if the subject,
while localizing the visual object, would be influenced by its
sound, coming from a position to the left.
The results of this series as first given to four subjects seemed
strongly to indicate that sound is efficacious as a factor in the
formation of the new visual coordination. The progress of these
subjects was noticeably more rapid than that of those in Series
A, for in the 10 day period their average remainder was less by
24 per cent and the average remainder for all the sittings, or
“total remainder,” less by 41 per cent. While none of the sub¬
jects in the standard group showed a higher total per cent of
readjustment than 75, and all but one fell below 60, only one
subject of the four in the sound group (B-i) fell below 60,
and one showed 100 per cent readjustment in 12 days. The
sittings in both groups were continued until the apparent limit
of improvement had been reached. Since on the average the
individuals in the sound group had one less sitting than the stand¬
ard group their smaller total remainder could not have been
due to more practice.
In the course of these experiments with sound, certain of the
subjects — and it happens the slowest ones — reported that they
did not associate the sound with the buzzer at all. It seemed to
come from another place, and so they got to thinking of it
merely as a signal for reacting. One even persisted in believing,
despite the assurances of the experimenter, that it was another
THE DEVELOPMENT OF A NEW SPATIAL CO-ORDINATION 49
buzzer, behind the apparatus, that was sounding. This suggested
the desirability of experiments to see if the fact of knowledge
or lack of knowledge that sight and sound came from the same
object, would make any difference in the rate of readjustment.
2. Second Group, Using Electric Bell
For this group it was necessary to use a sounding object in
which the vibration at the time of sounding should be clearly
visible to the subject. A “midget” electric door bell 3.5 cm. in
diameter, mounted and made adjustable like the buzzers, and very
similar to them in size and appearance, was used. The little
hammer, painted a bright red, vibrated conspicuously when the
bell was sounded. For the group in which the vibration was to
be invisible, a small brass “wing” was made which could be
quickly screwed to the upper part of the bell, and which effectively
prevented the subject from seeing the vibrating hammer from
any angle.
For these experiments with the bell the instructions to the
subject were essentially as in B-i, except that for the group in
which the vibration was visible the attention of the subject was
called to the energetic tattoo which the little red hammer kept up
when the bell was sounded.
Three subjects were used for the first group (B-2-a) in which
the vibration was visible, and three for the second group (B-2-b)
in which the vibration was invisible. The sittings were continued
until the limit of improvement had apparently been reached — for
this group, for about 30 sittings.
The results of the experiments with the bell were inconclusive.
There was no appreciable difference in either rate or amount of
readjustment. In fact the individuals in group b, who did not
have the objective assurance that the sight and sound belonged
together, showed on the average a slightly higher rate and amount
of improvement than those in group a. Their average 10 day
remainder was only 8 cm., while the corresponding remainder for
the three in group a was 9.5 cm. The results of both groups
were indeed strikingly like those for B-i.
After the experiments with the bell (B-2) two more subjects
50
MARGARET WOOSTER
were tested out for io days in the B-i series with the buzzers.
Both of these subjects (R. and H. E. C.) showed a very small
amount of readjustment, their remainders for the io-day period
being 14 cm. and 12 cm. respectively, and the per cents of read¬
justment only 27 and 32. This brought the average in group
B-i so low that on comparing the two groups as a whole, we find
a far less significant difference between the standard and the
sound groups than had appeared before. The superiority of the
sound group over the standard group was by these two additions
reduced in regard to the 10-day remainder from 24 per cent to
14 per cent and in regard to the 10-day readjustment from 26
per cent to 18.5 per cent. It is a question whether the small per
cent of improvement of these two subjects does not indicate
merely a lack of general susceptibility to readjustment, an in¬
dividual peculiarity that certainly exists. Unfortunately their
sittings did not extend beyond the tenth, and so there is no way
of telling whether, like O. B. B. in the standard group, they might
have shown a spurt of progress later on.
The individual and group results for all 3 of the B groups are
given in Table IV. The results for B-2-a (vibration visible) and
B-2-b (vibration invisible) are combined after B-2-b, since there
is no esesntial difference between them.
The figures for auditory accuracy reveal a good deal of in¬
dividual consistency considering the relative crudeness of the
arrangements. While there are wide limits of variability among
the different members of the group, the average mean deviation
for the group for all four positions being 6.3 cm., the individual
variability is less. The highest mean deviation for any individual
is 5.1 cm., while the lowest is 3.6 cm. The distance between the
four different positions of the buzzers, it will be recalled, is 13
cm. All of the subjects, therefore, were able under normal con¬
ditions not only to distinguish by sound alone the four different
positions, but within this range of 13 cm. quite accurately to
localize the particular source of the sound.
Under the conditions of distorted vision the great majority of
the subjects were conscious as soon as the sittings started of the
approximate actual position of the sound. In general they re-
THE DEVELOPMENT OF A NEW SPATIAL CO-ORDINATION
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52
MARGARET WOOSTER
ported that it seemed at each trial to be to the left of the buzzer,
estimating the distance to be from 6 to 30 cm. from its apparent
position. Subject C. S., in group B-2, is the only one who thought
for a while that the sound was to the right, but she soon dis¬
covered her error.1 Subject M. M. (group B-2) is the only one
in the series (including 15 subjects) who did not at any point
in her sittings localize the sound as to the left of the apparent
position of the object.
In considering the remainders and per cents of readjustment in
the sound series it will be convenient to deal with the group re¬
sults. In Table V, p. 58, is a summary of the results by groups
of A-i, the standard group of seven subjects, using four buzzers;
B-i, the first sound group of six subjects, using one buzzer; and
B-2, the second sound group of 6 subjects, using the bell. The
TABLE V
Summary of Group Results for Series A and B
Group
No.
Subj .
Av.
L.D.
R.
10-da.
R.
Total
Sit¬
tings
Percent
Readj.
10 da.
Percent
Readj.
Total
A-i-a
7
19. 1
12.5
8.7
21
35
56
A-i-b
4
17.7
10.6
9i
22
38
(47)
B-i
6
18.3
10.8
7-7
22
4i-5
(73)
Improvement of
B-i over A-i
13-6%
u.5%
I
18.5
(30.3)*
B-2
6
19.6
8.0
2.8
29.5
64.0
87.5
A(i-a and i-b)
11
18.4
II-5
8.9
22.0
36.5
(47)*
B(i and 2)
12
19
9.4
5-3
25-7
527
80
Improvement of
B over A
17.2%
40%
44%
(70%)*
*For four subjects only.
1 Toward the beginning of her sittings, C. S. even reported at one time
that she “saw the experimenter in one place and heard her voice in another”
(to the left). It is of interest here to note that M. O. W. (in series A-2)
first discovered the direction of the prismatic deviation through noticing
a similar discrepancy between the sound of the experimenter’s voice, and
her position as reported by sight.
)ev i a-tiO'tL m c erit i, Trt. ale, rs
THE DEVELOPMENT OF A NEW SPATIAL CO-ORDINATION 53
Fig. VI. Auditory Series.
combined results of B-i and B-2 and the combined results of
A- 1 -a and A-i-b (without knowledge) are also given.
The group curves for A-i are shown compared with the group
curves for B-i in Fig. X. Specimen curves for B are given in
Fig. VI.
From an inspection of these tables and curves it will be seen
that there are some indications that sound is an influential factor
in the process of readjustment. Comparing group B-i with the
standard group in which the buzzers were not sounding, we
find for the io day period a remainder less by 13.6 per cent than
that for the standard group, and a per cent of improvement 18.5
per cent greater. If we combine the results for A-i (with knowl-
54
MARGARET WOOSTER
edge) and A-2 (without knowledge), and compare them with the
combined results for B-i (using buzzer) and B-2 (using bell),
we find a still greater difference. The io day remainder for the
sound group is now less than that for the standard group by
17.2 per cent. The amount of readjustment for 10 days is greater
by 44 per cent.
Now while these differences, considering the large amount of
individual variation, by no means justify even the positive con¬
clusion that the sound had any influence at all in forming the
new coordination, they certainly do indicate the probability that
sound may be a factor.
An indication that sound as employed in our experiments may
be a factor in the formation of the new coordination, is the
fact that some subjects report that they feel a positive “pull”
in the direction of the sound, or in other words, toward the actual
position of the buzzer. A. C. W., for instance, in his later sittings,
felt such a tendency. Localizing the buzzer as it appeared to be,
he described as like “pushing up stream.”
This consideration is offset by the fact that a majority of the
subjects not only felt no “pull”, but paid very little if any atten¬
tion to the sound. The report was common that the sound served
merely as a signal for reacting, or as a sort of “orchestral ac¬
companiment”. Several, though they always localized the sound
— as to the left — felt that it made no difference in their re¬
actions. The most striking negative evidence occurs in the case
of M. M. (group B-2 ) who, though she made steady progress
and finally made a readjustment of 88 per cent, reported that she
was not at all conscious that the sound was to one side of the
buzzer, and did not even know until the very last the direction of
the distortion. (See M. M’s curves in Fig. VI.).
One subject, K. J., localized the sound as to the left, and
mentioned noticing it frequently. It was impossible to get him
to adopt a naive attitude toward the experiment, and it was
quite evident that he was determined to resist the suggestion that
occurred to him that the sound was expected to influence him,
as these typical remarks indicate: “Of course you realize the
sound doesn’t make a particle of difference,” and “Why are you
THE DEVELOPMENT OF A NEW SPATIAL CO-ORDINATION 55
sounding the buzzer at all?” In K. J’s curves given in Fig. VI
we see an actual progressive regression from the actual posi¬
tion of the buzzer, a unique situation among the 72 subjects. It
seems plausible that the regression may be due to the unconscious
influence on the localizations of the stubborn determination not
to be influenced by the sound.
As a matter of fact, suggestive as the above reports of sub¬
jects are as to the factors which did or did not influence them,
they have not a particle of value as scientific evidence. A sub¬
ject might be sure, as M. R. G. was in series A, that he was reach¬
ing to the same point each time, and yet actually be steadily ad¬
vancing to the left, influenced by factors of whose existence he
was entirely unaware. Similarly, subjects who reported that they
paid no attention to the sound may nevertheless have been in¬
fluenced by it, just as people may respond to irritating stimuli
during sleep, or waken if an accustomed stimulus ceases.
An attempt to see whether the sound might cause additional re¬
adjustment after a subject had reached the limit of improvement
in the standard series, proved fruitless as far as gaining definite
evidence was concerned. This is what might have been expected,
for as has been pointed out, it had been found that some subjects
in the standard series whose curves remained on a level for
some time, showed unexpectedly new progress in readjustment.
The fact, however, that four out of the five subjects tested in
this way did show at least a slight improvement immediately
after the introduction of sound, is worthy of attention. The *
subject whose curves exhibited no change whatever on the in¬
troduction of sound was M. W., the writer, who was, it happens,
the only one in the standard series who showed no progress in
that series. The improvement shown by M. R. G. and D. S. is only
what might have been expected had no change in conditions been
made.
In series A-2, however, the increase in readjustment of M. O.
W. and of M. Me F., after the introduction of sound, seems
possibly significant. The curves of M. O. W., which after 28
sittings had remained on a level for six sittings, showed an average
rise of 2.5 cm. in the first sitting in which sound was given. In
56
MARGARET WOOSTER
the next 16 sittings the per cent of readjustment increased from
37 to 45. The curves of M. McF., which after 35 sittings had
remained at a level for 10 days, showed a slight rise during the
three days after the introduction of sound (an average rise of
3.4 cm.). There was then a slump due to a fortnight’s vacation
and a 10 days’ absence on account of illness, after which the
curves showed a steady rise for nine days and a total advance
over the record for the sittings without sound, of 34 per cent
in amount of readjustment, while the remainder decreased from
8.6 cm. to 4.2 cm.
Such facts as the above may well make us hesitate before
concluding that sound has no efficacy in our experiments. Another
aspect of the situation is this: Inasmuch as subjects in the
standard series have shown a great deal of individual difference
in susceptibility to whatever factors make for improvement, may
it not be that some subjects are influenced by the sound and
others not? May not the unusually rapid progress of R. D. and
of C. S. be correlated with their interest in the sound and its
location, while others are not similarly influenced? Here of course
the influence of sound, if there be any, may be said to consist mere¬
ly in the emphasis of the direction and amount of distortion. The
situation is so complex, and there are so many possible factors
that it is in fact impossible to conclude from the slight evidence
we have, that sound is efficacious in these two cases.
Even if sound does have some influence in the process of read¬
justment, it is clear that in our experiment, that influence is slight,
and not susceptible of quantitative measurement. As an illustra¬
tion let us take the case of R. D., who showed a readjustment of
100 per cent in 12 sittings. From an inspection of her curves in
Fig. VI, it is seen that for 10 days after attaining an approx¬
imately correct localization of the buzzers, the curves fluctuate
about the same general level. Now if it were the sound of the
buzzers that was determining her localizations, the average for
these 10 sittings should roughly coincide with her average normal
auditory localization. But as a matter of fact R. D. localized the
sound of the buzzer normally over 6 cm. to the right of its actual
position. (See Table IV.) While the sound may have influ-
THE DEVELOPMENT OF A NEW SPATIAL CO-ORDINATION 5 7
enced her, then, it was not by virtue of exerting a definitely meas¬
urable “pull” toward a certain particular position.
In this connection it is pertinent to note the fact that while
the exact localization of the sound is unstable and shifts within
rather wide limits, it is for the great majority of the subjects at
first a relatively independent matter. At the begining of the sit¬
tings the sound is clearly assigned to a position definitely to the
left of the object as seen. It is only as the sittings progressed and
readjustment took place that the discrepancy between sound and
sight was reported as becoming less. Many of the subjects re¬
ported that at the close of the sittings sight and sound seemed
to be at last together, and the finger to “feel” in the right place
too.
Now while the sound comes finally in the process of readjust¬
ment to be “pulled over” to the sight, the subjects were not so
suggestible on this point as some of Stratton’s observations might
lead one to expect. The localization of the sound in our experi¬
ments is a relatively independent matter, changing only gradually
in response to the demands of the practical situation.
The following conclusions may be drawn from the experiments
on sound in series B :
1. There is evidence that sound may have a slight influence
in the formation of the new spatial coordination developed under
the conditions of our experiment, especially for some subjects.
2. If sound does have an influence, this influence operates
in general without awareness of that fact on the part of the subr
ject.
3. The fact of perceiving or not perceiving the direct con¬
nection of the sound with the vibrating visual object, has under
the conditions of our experiment no influence on the rate or
amount of readjustment.
4. The conditions of our experiment are not definite enough,
especially in the matter of directions to subjects, to insure a
fair test, of the efficacy of sound as a factor in the formation of
the new coordination. There is need for a better experimental
technique in this matter.
58
MARGARET WOOSTER
LOCALIZATION WITH TOUCH
The next series, C, was designed to determine the influence
of contact with the buzzer upon the rate and amount of read¬
justment to the changed visual conditions. For this series one
buzzer only was used. This was shifted from one of the four
positions to another according to a regular order. The slit at the
back of the cover was widened just enough to permit of lower¬
ing the buzzer half way down through it. The subject, on making
a correct localization, would thus touch the lower half of the
buzzer without seeing his finger. The contact with the relatively
cool smooth buzzer was distinctly different in quality from the
usual contact with the wood forming the back of the apparatus.
Contact was the sole means of determining the actual position
of the buzzer. It was not sounded. The localizing finger could not
be seen by the subject even though the slit was wider than in the
preceding series, because the narrow wood strip one cm. in thick¬
ness (which formed the front of the frame supporting the slid¬
ing cover) acted as a sort of screen. As in the preceding series,
in order that the subject might not find out the extent of his
error by visual means, through seeing the experimenter’s move¬
ments in getting the records, the black curtain was drawn after
each localization.
i. Passive Touch, as the Result of Chance Success
In the first group of experiments with touch the subject
localized the buzzer exactly as in the standard series, reacting
to its apparent position, but with the knowledge that when he
made an objectively correct localization he would touch the
buzzer. In other words he knew each time he reached out that he
was missing the buzzer. There would be no actual contact with
the buzzer, then, unless by accident or until almost complete read¬
justment should occur.
In the case of the three subjects in this group, it was found
that the knowledge each time that the localization was wrong,
had apparently no effect upon the rate of readjustment. The
results were in all respects like those of the standard series. (See
THE DEVELOPMENT OF A NEW SPATIAL CO-ORDINATION 59
Table VI.) Complete readjustment occurred in the case of only one
subject. In his case it was plainly due to an accidental direct con-
TABLE VI
Groups C- 1 ( Active Touch) and C-2 ( Passive Touch)
No. of
Visual Acc.
Av.L.D.
Rem.
Rem. Per Cent
Subjects
Sit-
53
66
79
92
1st
10 da.
T o'tal
Readj .
tings
trial
10 da.
C-i
*
T. L. W.
18
53-5
66.5
80.6
937
13.
+ 1.4
+ 1.4
90.
M. K.
10
53-9
65.8
78.3
91.0
21
18
14
R. J. B.
20
54-i
66.8
78.6
91.2
22.3
19-3
19-3
13
C-2
F. D.
11
534
67.0
79-9
92.4
24.9
•5
# #
98
D. B.
13
55-0
67.6
81.0
94.0
234
34
2.0
85
M. B.
10
53-0
66.0
79-7
91.9
19.1
.23
• •
99
G. B.
12
52.8
66.8
79-3
93-0
20.4
1.0
•55
95
F.
10
53-9
66.6
80.0
92.2
21.2
.96
• •
95
Average
11
1.02
944
R. D.
9
53-2
66.0
78.3
91.7
84
10.2
• •
45
tact with the buzzer. The other two did not approach sufficiently
close to the buzzer to admit of the occurrence of a chance touch.
One of these subjects, R. J. B., was one of the few of the entire
number of 72 subjects who, like M. W. in the standard series,
made no significant progress at all, although she had 20 sittings.
The results for this group, then, were indeed essentially like those
of A- 1, and served only still further to confirm the conclusions
drawn from them.
The results of one subject of the three, however, furnish a bit
of interesting evidence. T. L. W. accidentally touched buzzer four,
at position 79, at the first localization in his fifth sitting. As a
result all the following localizations were much nearer the actual
position of the buzzer, although T. L. W. was not conscious of
the change. (See T. L. W.’s curves in Fig. VII.) The curves
for all the positions, which had for the four sittings shown no
advance at all, rose after this one contact experience an average
of 6. 1 cm. in the one sitting! Moreover, the influence of the
contact was strongest for the particular position where it occurred,
(buzzer 3) and least for one farthest away (buzzer 1). At the end
of the 10th sitting there was complete recovery for buzzer 3, but
6o
MARGARET WOOSTER
for buzzer i recovery was not complete until the 18th sitting. All
this regular and rapid readjustment took place while T. L. W. was
reacting automatically to the position of the buzzer as it appeared
to him!
The case of T. L. W. shows in a striking way the marked
efficacy of direct contact as a factor in readjustment. But it is
plain that with the instructions used in this group, direct con¬
tact would occur only rarely, in the case of a few subjects.
The results of the group as a whole show only that the ob¬
jective knowledge of error, when contact was not felt, had no
effect in hastening readjustment. This is significantly in line with
the results of Series A-i-b (without knowledge).
2. Active Touch, as a Check at Each Localization
In the next series the aim was to test the influence of the factor
of active touch as a check at each localization. For this group the
subject reacted, as in all the series, to the apparent position of
the buzzer. But after each localization made in that manner, he
checked the accuracy of his localization by actual contact, accord¬
ing to the following directions:
“When you have touched the board, keep your finger in position
while the screen is adjusted and until the experimenter says ‘All
right/ Then, not taking the finger from the board, move it along
until you touch the side of the buzzer. Then put your finger tip
squarely on the black line as it extends beneath the cover. Now sit
back in the chair and wait for the next ‘Ready’ signal.”
After the first localization the subject would move his finger
uncertainly along the board, as often in the wrong direction as
the right one, and would usually not touch the buzzer until after
some retracing. After this there would be, after each localization,
one natural movement in the right direction, leading to the contact
experience. Of course with this revised procedure we do not
have as the additional factor a simple contact value, but one com¬
plicated with kinaesthetic stimuli. In other words we have active
or exploratory, rather than passive touch.
In dealing with the results of series C, D, and E we must keep
in mind the fact that in these groups, as pointed out in the dis-
THE DEVELOPMENT OF A NEW SPATIAL CO-ORDINATION 61
cussion on pp. 18 and 19, the per cent of readjustment is a less
reliable measure of improvement than in series A and B. This,
it will be remembered, is due to the fact that in these later series
the readjustment occurs so rapidly as to make extremely am¬
biguous the figures expressing initial linear deviation.
An illustration from series C-2 of the fact that readjustment
takes place within the first four trials is afforded by the results
of D. B. From Table VI, p. 64, it is seen that her initial devi¬
ations for positions 53, 66, 79, and 92 are 24, 23.1, 27, and
19.5 cm., respectively. Now according to the linear deviation
calculable from trigonometric formula on the basis of the angle
of the prisms and the angle at each of these positions,1 the great¬
est deviation should be at 53, and the amounts should be succes¬
sively less for the other buzzers. The fact that instead the order
of greatest deviation is 79, 53, 66, and 92, is easily accounted for
by the fact that the trials were given in just that order. Thus
for each successive trial we have a decrease in deviation, due to
the tendency to readjustment — a decrease so marked as to obscure
the common objective difference in linear deviations due to angle
and position.
The individual results for series C are given in Table VI, and
specimen curves in Fig. VII. In the table a plus sign before a
remainder indicates that it represents “over-correction”, or local¬
ization to the left of the actual position of the buzzer. The curves
for four of the five subjects in group C-2 exhibit a uniform
and gradual, but very rapid readjustment. On the average the
remainder of these subjects at the end of the 10th sitting is only
1.02 cm., and the per cent of readjustment is 94.4. One subject,
R. Dixon, is a notable exception. Apparently touch is not effective
in her case at all, for her very lowest remainder is 10.2 cm.,
and after that point (at the sixth sitting) her curves recede again
until at the ninth sitting they are nearly as low as at the beginning.
These results are decisive evidence that touch is a powerful
factor in the formation of the new habit of spatial reaction. That
one subject was apparently not influenced by this factor, only in¬
dicates again the existence of marked individual differences in
62
MARGARET WOOSTER
Nu.Wber o[ silU
Fig. VII. Tactual Series,
c sin B
1 b — - . See p. 42.
sin C
the matter of adjustment to spatial relations. The gradual slope
of the curves, the striking correspondence for each subject of
the curves for the four different positions, and the general sim¬
ilarity of the curves of the five subjects who did readjust, all
THE DEVELOPMENT OF A NEW SPATIAL CO-ORDINATION 63
point to the operation of a consistently powerful stimulus to read¬
justment.
The fact that the readjustment did not occur on a conscious
level needs to be emphasized here. At each trial the subject reached
out naturally and automatically toward the buzzer as it appeared
to him. There was, after each localization, the knowledge that the
actual object had been missed, and the awareness through previous
tactual-kinaesthetic experience of its approximate location. But
since there was no conscious attempt to correct, the “re-harmon¬
ization” evidently took place in response to a need for a practically
effective response, of which the subject himself was not clearly
aware.
LOCALIZATION WITH VISUAL PERCEPTION OF
AMOUNT OF DISTORTION
The aim of series D was to determine the relative influence of
sight of the localizing finger after the response, in the formation
of the new spatial coordination. For this series the slit at the back
of the cover was made wide enough to permit the introduction
of the finger tip when a localization was made, in such a way
that the tip only of his finger was visible to the subject. At
the same time the buzzers were raised to such a height that
the finger tip, when appearing just beneath the black line, did
not come in contact with the buzzer. All four buzzers were
used. Instructions and general procedure were exactly as in the
standard series. Thus by having the subject react to the apparent
visual position of the buzzer, we were able to test the effect of
visual perception of the amount and direction of error.
Ten subjects took part in this series. The results are given in
Table VII, p. 67, and Fig. VIII. The results of E. B., M. L. P.,
P. and P. I., while given in the table, are not included in the
general averages for the group. This is because they had less
than 10 sittings and did not quite reach complete readjustment.
In this table, as in Table VI, a plus sign before a remainder
indicates an excess of localization to the left.
It was perhaps more difficult in this group to maintain a per-
64
MARGARET WOOSTER
XLA
fectly naive and uncritical manner of response, with no conscious
effort to correct, than in any other series. But there were more
subjects, and moie highly trained subjects, in this group than
in any other group. They all reported that the process of read¬
justment was pui ely effortless and they were uniformly surprised
when the distance from the buzzer first began to decrease. That
THE DEVELOPMENT OF A NEW SPATIAL CO-ORDINATION 65
the process was spontaneous and automatic is indicated by the
strikingly gradual slopes of the curves and their uniformity for
the four different positions.
The curves of all 10 of the subjects in this group show a
very rapid readjustment, amounting in 10 sittings to an average
per cent of readjustment of 97, with a remainder of only .4 cm.
This shows that in our experiment, vision and touch seem to be
almost equally powerful factors in effecting a readjustment to
the new spatial conditions. The curves for the groups (C and D)
in Fig. X exhibit about the same general height and slope.
A study of both the curves and tables, however, reveals sig¬
nificant differences. In the first place the group curves seem to
indicate that the rate of readjustment is more rapid for series
D than for series C. The curves for the sight series, D, are
consistently higher on the average than those for the touch series,
C. Especially striking is the difference for the first two sittings.
On first thought this would seem to indicate a more rapid initial
readjustment for sight than for touch. The numerical results in
Table IX, p. 73, however, suggest that this may not be really the
case, and that the average amount of deviation is so much less
in the case of sight, not because there was a good deal more
progress within the first sitting, but because the average initial
deviation for the group was less by 4.5 cm.
But why is the average initial deviation so much less than in
the case of the sight series? There are two possible reasons. First,
it may be due to mere individual variability and the lack of a
sufficient number of cases to strike a typical average. There are
only ten subjects in Group D and seven in Group C. Second, it
may be due to so rapid a readjustment in the case of the sight
series that the average deviation for the four buzzers combined
may be significantly less than the deviation for the first buzzer
localized in the sitting, which was in this group buzzer 92.
Now as a matter of fact the second explanation proves on
analysis of the results to be the true one. While the average
deviation for all four buzzers is 17.6 cm. for the sight series, the
deviation for buzzer 92 is 21.3 cm. for the group, a difference
66
MARGARET WOOSTER
of 3.7 cm. Had the first buzzer to be localized by the group been
53 or 66, this deviation would have been still greater, owing to
the fact that the standard objective deviation for buzzer 92 is
the least of the four buzzers. The average initial deviation for
the other three buzzers is markedly less than for buzzer 92, be¬
cause the process of readjustment set under way by the first
localization of buzzer 92 is already proceeding rapidly.
Taking these facts into consideration it is clear that the average
deviation for series D, which is calculated on the basis of the
average of the initial trials only for each position, is smaller
than that for series C for the reason that there is indeed a very
rapid readjustment within the first four localizations in the first
sitting. Individual variability might account for a small amount
of difference in the average initial localizations for the two groups,
but it could not possibly in itself account for the striking differ¬
ence we actually find.
The second significant difference between the results for the
sight and the touch series is found in the fact that not only
is the rate of readjustment for the former greater, but the ab¬
solute amount of readjustment effected within the given 10 day
period is greater. The average remainder for the visual group
is only .4 cm., as contrasted with 1.02 cm. for the tactual group.
(Table IX.) In the visual group four out of the seven subjects
who took 10 sittings showed a complete readjustment, while not
one of the seven subjects in the tactual group effected a complete
readjustment. Another indication that the influence toward read¬
justment afforded by the sight of the discrepancy was more
strongly operative than the tactual factor, is the circumstance
that in the visual group five out of seven subjects show a small
average “over correction" (.15cm.) while no individual in the
tactual group showed an average “over correction” for the four
positions. It is as if, having felt a strong impetus toward read¬
justment, the subjects in the visual group were carried a little
way past the goal by the mere force of inertia.
We had the opportunity to find out whether sight was a more
powerful factor than touch in the case of one individual, owing
to the fact that after a long series of sittings with touch (19)
THE DEVELOPMENT OF A NEW SPATIAL CO-ORDINATION 67
she showed absolutely no further improvement. The factor of
sight was then substituted for that of touch with the result that
an immediate improvement set in, and after 13 sittings the sub¬
ject (M. W., the writer) had made a complete readjustment.
A comparative study of the results for series C and D, then,
indicates that the factor of sight as used in our experiments is
more efficacious in the formation of the new coordination than
the factor of touch.
TABLE VII
Visual Perception of Amount of Distortion
Sub¬
jects
No. of
Sit¬
tings
53
Visual Acc.
66 79
92
Av.L.D.
1st
trial
Av.Rem. Total
10 Per Cent
days Readjust.
J.
L.
B.
1 7
53-3
66.0
78.9
92.2
20.4
14
93
P.
J.
R.
10
53-8
66.1
78.7
91.6
16.0
2.3
86
G.
10
53-0
66.3
79.0
92.0
20.0
.2
100
A.
D.
U.
12
52.7
66.5
98.8
9i-3
15.2
.2
99
D.
H
. B.
6
53-6
66.2
79-3
91.8
14.5
.15
101
F.
A.
K.
11
52.7
66.3
79-
91.2
17-3
.1
100. 1
F.
R.
8
52.5
66.9
78.8
9i-5
19.8
.1
100
Average
10.6
17.6
4
97
E.
B.
7
534
64.6
78.1
91.9
18.7
•5
97
M.
L.
P.
6
53-5
65.0
78.2
93-5
16.2
4
97
P.
I.
7
53-i
65.2
78.6
92.3
134
1. 1
92
LOCALIZATION WITH TACTUAL-KINAESTHETIC
CLUES FROM LEFT ARM
Perhaps one of the strongest habitual simple space codrdi-
nations employed in daily life is the coordination between right
and left hand and arm movements, so necessary for grasping and
handling objects. Were some form of this coordination broken
up by the wearing of the prismatic glasses, it would seem that
there would be an unusually strong tendency to re-form the
coordination under the changed visual conditions. It was the aim
of series E to see what is the relative strength of this tactual-
kinaesthetic influence toward readjustment as compared with the
other factors investigated.
The procedure was as follows. The subject was seated at the
apparatus in the usual position, wearing the glasses. While his
eyes were closed his left arm was extended out over the cover by
68
MARGARET WOOSTER
the experimenter, and he was directed to bend the left index
finger so that it would extend downward at the back of the
apparatus through the slit, which had been sufficiently widened
for this purpose. When his finger was in position the subject was
permitted to open his eyes. He was then directed to localize his
left index finger as in the normal series, by a direct movement
of the right index finger to the part of the left finger extending
beneath the cover. He was, as in the other series, to localize the
finger as it was visually perceived, disregarding the fact of dis¬
tortion. The experiment thus tested the influence upon localization
of clues as to the correct position of the finger derived through
the tactual and kinaesthetic senses.
The slit was so wide in this series that in order to prevent
sight of the localizing finger by the subject it was necessary to
provide a movable cardboard strip to cover the movements of
the finger. In the middle of this strip, which is 56 cm. long and
8 cm. wide, is an aperture shaped like a half moon through
which the left finger of the subject was extended. At each trial
this opening was set at the desired position, 53, 66, 79, or 92,
as the case might be. The same order and number of trials and
the same length of interval were maintained as in the other series.
With this manner of procedure the subject was kept just as
much in ignorance of the direction and amount of the distortion
as in the standard series. The only difference was that in this series
tactual-kinaesthetic sensations from the left arm afforded clues to
the actual position of the object. Had the subject been permitted
himself to extend his left arm over the cover and his finger down
through the aperture, he would have gained not only knowledge of
the nature of the distortion but practice in overcoming it. It was
for this reason that the experimenter put the arm of the subject
in place herself, and was very careful that the subject should
withdraw it while his eyes were closed and the curtain still in
place in front of the line of localization.
Six subjects served in series E, for 10 days each. Results are
given in Table VIII, p. 71 and Fig. IX p. 69. The most striking
feature of the data is the fact that for all of the subjects the
THE DEVELOPMENT OF A NEW SPATIAL CO-ORDINATION 69
XTTHL
initial linear deviations are very much lower than in any of the
other series. The average linear deviation for this group is only
9.5 cm., while the lowest average for the four other series, that
of series D, is 17.6 cm. The average even for the first position
localized, 92, or buzzer 4, is only 10.3 cm. This fact can apparently
mean only one thing, viz., that the tendency to effect a practical
coordination of the movements of the two hands is so strong that
it is impossible with our glasses to break it up, although the sub-
70
MARGARET WOOSTER
jects acted in innocent and even ignorant good faith in trying
accurately to localize the left finger as it visually appeared to
them. In other words, “readjustment” to the changed visual con¬
ditions is on the average more than 50 per cent effective prior
to the first localization. Moreover, since the subjects reported that
they were unaware of the direction of the distortion, this “read¬
justment” was unconscious on their part and occurred solely on
the basis of the retention of habitual kinaesthetic attitudes.
In the tactual-kinaesthetic series, it is to be kept in mind that the
influence of the sensory incentive to readjustment was operative
before the first localization. In the auditory series a similar
situation prevailed, since the sound afforded a clue as to the
actual position of the buzzer before the first trial was made. In
the sound series, however, the influence of such a condition was
not apparent, while in the tactual-kinaesthetic series it was very
marked. In no other series could the clues be perceived before
actual localizing movements began.
A second striking feature of the results peculiar to this par¬
ticular series is the fact that of the six subjects, three showed
no continued improvement over their first deviations, while the
other three made exceedingly rapid progress and soon overcame
their small initial remainders. In no other series have so large a
per cent of the subjects failed to readjust. The conclusion is sug¬
gested that there may be much more individual variation in the
extent to which this sort of tactual-kinaesthetic factor is effective,
than is the case with sight and touch.
Such a conclusion finds support from the consideration of par¬
ticular cases. Subject T. K., for instance, readjusted very rapidly,
attaining almost 100 per cent recovery at the fourth sitting. He
then forged on ahead beyond or to the left of the actual position of
the finger, showing an average overcorrection of 1.7 cm. before
he settled down again to an approximately correct localization.
The curves of the other two who readjusted exhibit merely a
slight fluctuation about the true position after recovery has taken
place.
It is the results of T. H. B. which most strikingly indicate
how helpless an individual may be under unusual conditions when
THE DEVELOPMENT OF A NEW SPATIAL CO-ORDINATION 71
left to depend upon kinaesthesis alone. Having made no read¬
justment during nine sittings, at the 10th T. H. B. was permitted
to reach out to what he thought was the actual position of his
finger, making a conscious correction. He felt sure that he could
do this accurately, even while wearing the glasses. His first con¬
fident move was to localize buzzer 1 (position 53) at 34, or 9 cm.
farther away than he had previously been localizing it ! During 20
repeated trials he was unable to find his left finger, missing it on
the average by a distance of 16.7 cm. to the right! Astonished, he
came back the next day determined to localize it accurately this
time, but only to repeat the performance of the preceding sitting
during 12 more trials. It was only when directed by the exper¬
imenter to reach out on the other side of the finger, that T. H. B.
did touch it by accident. After this, he was able to localize it with
a fair degree of accuracy.
A comparison of the average results for the three subjects in
this series who did readjust, with those of other series, reveals
of course a striking superiority in both quickness and amount
of readjustment. The curves for series E in Fig. X are higher
at every point than those of any other curves. This holds true even
for the end of the 10 day period, for on the average an excess
of readjustment occurred. While the 10 day remainders for series
A-i, B-i, C, and D are respectively 12.5, 10.8, 1.0 and .4 cm.,
that for series E is + .49 cm., representing a positive extra read¬
justment. This tendency to overcorrect was soon checked by all
of the subjects who showed its influence. The overcorrection,
TABLE VIII
Tactual-Kinaesthetic Clues from Left Arm
Sub¬
jects
No. of
Sit¬
tings
53
Visual Acc.
66 79
92
Av.L.D.
1st
trial
Av.Rem. Total
10 Per Cent
days Readj.
T. K.
10
55-6
66.7
80.7
93-6
9-4
+ 1.7
118
W. M. S.
10
53-8
66.4
79.6
92.2
8.0
.76
9i
M. M.
10
52.0
65-3
78.9
91.6
10.0
+•47
104.2
Average
9
9.1
•49
104.6
N. McL.
9
53-8
65.8
79.2
92.0
II.O
97
12
R.
10
52.9
66.2
79.0
92.3
15.1
13.0
13
F. H. B.
, 11
54-5
66.9
80.1
92.9
II. I
9.6
13.6
Average
12.4
10.8
12.9
72
MARGARET WOOSTER
Www^vvw' - -
•A.
r
Standard. •
oca C3C3
With knowledge
•Without knowUAq
Undlstorteil
- Auditory
Tactual
- Visu aA
— — Tactual -
kimaesthetU
t — i — i — i — i — T
1ai2 a 4- 5. b 7
NirmW of sitTi'aq
Fig. X. Group Curves.
THE DEVELOPMENT OF A NEW SPATIAL CO-ORDINATION 73
then, indicates apparently nothing more than an unusually strong
impulse toward readjustment.
In considering this striking superiority of the tactual-kin-
aesthetic factor it must be held in mind that we have after the
first sittings another factor lending its weight to the already
strong influence of the tactual-kinaesthetic clues from the left
arm. This comes from the fact that as soon as the left finger
is accidentally touched by the right arm, we have the operation
of the direct contact factor the influence of which was seen to be
so great in series C. It is no wonder, then, that after actual con¬
tact, readjustment is completed almost immediately.
TABLE IX
Summary of Results for All Series
No. of Factor or
Series Condition
No. of
Sub-
j ects
Av. No.
Sit¬
tings
Ini¬
tial
L.D.
Rem. Rem.
10 da. Total
Percent Percent
Readj. Readj.
10 da. Total
Mean
Dev.
10 da.
Standard
A- 1 -a with
•Knowledge
7
cm.
19.1
cm.
12.5
cm.
8.7
35-5
56.0
cm.
8.0
Without
A-i-b Knowledge
4
17.7
10.6
9.1
38.8
(47)
10.0
A-i (a & b)
ii
22
18.6
1 1.8
8.8
36.0
53-0
8.8
Sound
B-i of Buzzer
6
18.3
10.8
7-7
41-5
(73)
10.5
Sound
B-2 of Bell
6
19.6
8.0
2.8
64.0
87.5
16.5
B (I & 2)
12
26
19.0
9.4
5-3
52.7
80.0
15-5
Active
C-2 Touch
5
10
21.8
1.02
94-4
3-9
Passive
C-i Touch
D Sight
7
10
17.6
•4
97.0
4-3
Tactual-
E Kinaesthetic
3
10
9-1
•5
104.6
9.0
IV
RETENTION OF THE NEW CO-ORDINATION
The question as to how long the new spatial coordination will
be retained, while not strictly pertinent to our main problem of
determining the relative influence of the various constituent fac-
74
MARGARET WOOSTER
tors, has nevertheless some bearing on the problem, since it con¬
cerns the stability of the new habit.
We made no effort systematically to investigate the amount
of retention in these experiments, or its relation to time of ac¬
quisition or the sensory factors concerned. But some weeks after
the conclusion of the experimental series we gave one sitting
each to such subjects as were still available — seven in all.
The trials were given in the same manner as in the original
sittings. The average of the five trials for each position was taken,
and the amount of readjustment shown was calculated. This was
compared with the previous highest amount of readjustment
to show the per cent of retention of the habit.
The results are given in Table X. Some individual cases of re¬
tention are striking. The per cent retained by K. E. L., after an
interval of 37 weeks, was 77. That of D. S., after 24 weeks, was
90. The most striking case of all, however, is that of H. L. K.
After an interval of two years and three months she was given first
the test for visual accuracy, without the glasses. In this test her
error to the left of her previous normal standard of visual ac¬
curacy was 3 cm., with an average deviation of only .9 cm. On
taking the 20 trials while wearing the prismatic glasses H. L. K.
showed a retention of 47 per cent of the progress made two years
before. Considering the fact that H. L. K. had originally only 12
sittings, this amount of retention is striking.
The results for all of the subjects who took the retention test
point, then, to a high degree of stability and persistence in the
new spatial coordination.
TABLE X
Retention
Subject
No. of
Sittings
Series
Approx. No.
of Weeks’
Interval
n •
jxeadj .
Later
Per Cent
Readj.
Per cent
Retention
D. S.
15
A-i-b
24
57
5i
90
T. K.
10
E
24
1 18
105
89
M. L.
6
D
30
97
78
30
T. L.
W.
18
C
24
78
100
78
K. E.
L.
3i
B
37
82
63
77
H. L.
K.
12
A-i-a
116
53
25
47
E. B.
7
D
30
97
86
88
THE DEVELOPMENT OF A NEW SPATIAL CO-ORDINATION 75
V
DEGREE OF SPECIFICITY OF THE NEW
CO-ORDINATION
Does the new spatial habit acquired by the subjects in this ex¬
periment carry over to a noticeable extent into normal situations ?
This question has a general importance theoretically in its bear¬
ing upon the whole Kantian and modern controversy concerning
the generality of spatial experience. It also has an interest for the
narrower purposes of the experimental investigator in the field
of space perception. Heretofore the attack on this question has
been in general theoretical and to an unfortunate extent contro¬
versial. If it should seem possible to throw light on the problem
by some such simple experimental procedure as we have em¬
ployed, then there would be promise of advance in future ex¬
perimental investigation of the problem.
It proved extremely difficult in this investigation to devise
methods that would secure a reliable check on this matter. As
soon as we freed the subjects from the rigid conditions imposed
at the apparatus in order to observe their behavior in normal sit¬
uations, we found operating many obscure factors the nature of
which it was impossible accurately to evaluate. We believe how¬
ever that certain tests we used do throw some light on the prob¬
lem, and give promise that in the future genuinely reliable factual
evidence can be secured.
Now if the particular spatial habit we are investigating really
does function in general situations, we should find the following
conditions to hold :
1. Subjects wearing the glasses at the apparatus should not
find the new o J‘ Ttion seriously interfered with should any
change in the gent*^ cy situation be made.
2. On the removal of the glasses the continued functioning
of the new habit should manifest itself in a disturbance of the
old or established manner of reaction. This should hold not only
at the apparatus table but for attempts to localize objects in or¬
dinary situations.
76*
MARGARET WOOSTER
3. Practiced subjects wearing the glasses should localize or¬
dinary objects with smaller error than unpracticed subjects.
4. Practiced subjects wearing glasses should be able to walk
about a building with more ease and efficiency than unpracticed
subjects.
These four general criteria we applied in our investigation. In
the first place in order to find out whether a change in the general
sensory situation interfered with the new coordination, we adopt¬
ed the following procedure. For three of the groups at the con¬
clusion of the trials with distorted vision, the chair in which the
subject sat was shifted 18 cm. to the right, and localizations were
obtained as before with the subject reacting from the new posi¬
tion. Now if the new habit was formed merely on the basis of a
definite position, with definite tactual and kinaesthetic stimuli, it
might be expected that it would be seriously disturbed or even lost
were a new position assumed. The shift in position of the chair,
however, made no significant difference in the reactions for any of
the 20 subjects who took this test. For five subjects in the stand¬
ard series, ten in the sound series, and five in the sight series, the
average difference between the last five trials for the shifted
position is only .3 cm. This small difference is positive, or in the
direction in which improvement would be expected. There is,
moreover, a negligible amount of individual variation, the dif¬
ference being very small in every case. Flence the readjustment
is general in the sense of not being limited to any particular
part of the apparatus.
To answer the second question two different procedures were
adopted. First the glasses were removed from the subject im¬
mediately at the close of the last sitting with distorted vision.
Then, still seated at the apparatus he was required to localize
the buzzers as they appeared to him visually, in the same manner
as before, but without the glasses, and of course without seeing
his finger.
If the readjustment had been a function merely of the partic¬
ular conditions of the practice series, with glasses worn, these
localizations with normal vision would have been objectively
correct, i. e., the subject would have localized the buzzers with
THE DEVELOPMENT OF A NEW SPATIAL CO-ORDINATION 77
approximately the same degree of accuracy as in the trials for
normal visual accuracy given at the beginning of his sittings.
All of the 23 subjects tested in this way, however, made a
large error to the left of their standard for normal accuracy. For
five subjects in series B, six in series C, nine in series D, and
three in series E, to whom the test was given, the average error
to the left was 9.3 cm. This means that the subjects, having
grown accustomed while wearing the glasses to localizing the
buzzers by reaching out some distance to the left of where they
looked to be, now retained the habit when the glasses were re¬
moved, and reached out confidently to the left of where the ob¬
jects objectively were. If the new habit had functioned in full
strength without the prisms, then the average error to the left
would have been 14.8 cm., the average amount of improvement
shown during the sittings by these 23 subjects. That it was in
fact 9.3 cm. (or 62 per cent of the original amount) indicates
a striking degree of transfer of the new formed habit to the
normal situation, considering the strength of the customary or
old association between object seen and reaching movement,
which on the removal of the glasses would be expected to exert
a strong influence.
The other procedure adopted for determining the existence of
an after effect from the wearing of the glasses was carried out
away from the apparatus. The subject, still wearing the glasses,
was seated at an ordinary study table and directed to reach out
and touch with the index finger certain objects which lay on the
table — an eraser, an ink bottle, and a thimble. This each subject
was able to do accurately, after a few trials to overcome the
small error to the right that he still made. Now the subject was
asked to keep on reaching out, touching the objects every few
seconds, and not stopping when the glasses were removed. When
he had started localizing the objects in this manner, the ex¬
perimenter quietly removed the glasses. For two of the four sub¬
jects given this test the after effect was striking. These two,
T. L. W. and K. E. L., continuing to reach out in the same way,
missed the objects each time by from two to four cm. to the
left, although they could plainly see their hands going in the
78
MARGARET WOOSTER
4
wrong direction. They were surprised and amused at the result.
Both reported a queer “pull” to the left and a feeling of effort or
strain as if something were holding them back. Thus in spite of
the existence of a sharp conflict between the established system
of localization and the newly acquired space habit, the latter con¬
tinued to exert an influence in this everyday situation. Moreover
it required a number of trials for both subjects before they
could again reach out and touch the objects accurately.
For the two subjects whose normal reactions were not thus in¬
fluenced, it seems that the sight of the arm and hand in reaching
out may have supplied an overwhelmingly powerful stimulus to
unconscious correction to the right while the movement was still
under way. Even for the subjects who did feel the after effects
the error was so small that it would have led to no difficulty in
making practical adjustments unless movements of great accuracy
were required; and it is quite possible that the effect was with
them only transitory. None of the other subjects after the removal
of the glasses reported any interference with normal reactions.
Even if the after-effect is slight and perhaps transitory, how¬
ever, this test is significant in showing definitely that even such
a rapidly acquired and simple spatial coordination as this may
function effectively enough to interfere with the longstanding
habits of reaction. It is unfortunate that the test was devised too
late to give to a larger number of subjects. Together with the
test at the apparatus however it furnishes clear evidence that the
new habit does exert an influence on normal reactions.
Our third criterion, that subjects who had learned to localize
the buzzers more or less correctly while wearing the glasses,
should be able with the glasses on, if the habit is general and
not specific, to localize ordinary objects with either no error or
a smaller error than unpracticed subjects, we subjected to test
in two ways. First, we had the subject sit at a study table, and,
wearing the prismatic glasses, localize objects placed in definite
positions in front of him. Second, we had him walk about the
room, pick up objects, walk down a long hall and the like, while
we carefully observed his behavior.
For the test at the study table we first tried the following
THE DEVELOPMENT OF A NEW SPATIAL CO-ORDINATION 79
plan. Five objects, — two ink bottles of different size and shape, an
eraser, a small box, and a thimble were placed in definite posi¬
tions on the table, about 20 cm. apart, and from 25 to 40 cm.
from the edge. The subject, wearing the glasses, was seated in
front of these objects, with his right arm resting on the table
parallel to the front edge. He was instructed to reach out at a
natural rate of movement and localize the object as it appeared
to him with his index finger. The experimenter first named the
object, and then at the signal “go” the subject reached out, letting
his finger rest where it happened to fall until the experimenter
had noted in centimeters the amount of error to the right.
The first tests given with this method showed it to be un¬
reliable. The errors were found to be very small and to decrease
markedly after the first trial. But far from indicating a transfer
effect this only showed that a powerful factor was operating
within the time of the test to decrease the amount of error. This
factor seemed evidently to be the sight of the arm, which, after
the reaching movement was started, would serve as a strong
stimulus to correction to the left. Such a conclusion is in line with
the statement of a number of the subjects that although they tried
honestly to locate the object as it looked to them, they felt a strong
“muscular urge” or “pull” to the left against which they had to
resist.
With the idea of at least partially obviating such a tendency
to correct and thus of getting a measure of the transfer effect,
we hit on the plan of having later subjects reach out very quickly
to the object, believing that there would thus be much less likeli¬
hood of the direction of the movement being changed, once
started.
Twenty-seven subjects took the test in this form. The numerical
results for all individuals are given in Table XI, p. 81. Although
two trials were given for each object only the first is given here.
In practically all cases the error was much less, approaching
zero, on the second trials. Since there was considerable variation
in the position of the subject’s chair, his distance from the ob¬
jects, and the order in which they were named, these results are a
very rough measure only of the relative amount of error, and it
8o
MARGARET WOOSTER
would be useless to attempt to deal with group averages and com¬
parisons. The individual results, however, are worth studying.
The objective errors due to the prismatic distortion would
have been from 20 to 35 cm., according to the position of the
objects. But the errors shown in the table are very much less.
The smallness of the errors however can not be due primarily
to transfer. This is shown in the first place by the fact that the
error markedly decreased after the very first trial. For example :
for the first object the error of E. B. in the Tactual Series is
20 cm. and for the second object only 7 cm. For F. in the Visual
Series the error for the first is 15 cm. and for the second 2 cm.
Subject F.’s remark, “I feel an irresistible pull to the left,” in¬
dicates the nature of the stimulus which influenced other subjects
though in lesser degree, to decrease their errors. Evidently the
sight of the arm in reaching and the visual perception of the
discrepancy between object and localizing movement, initiated
kinaesthetic impulses so strongly in conflict with the reaction
originally released as to modify its direction.
A second type of evidence that the smallness of the errors is
not the direct result of transfer of the new space habit, lies in the
consideration that there is no apparent relation between the
amount of error in this test and either length of practice or the
amount of readjustment attained. The results of M. W. and M. K.
in the Visual Series illustrate this point. M. W., after 63 sittings
and complete readjustment, still made an extremely large error;
while M. K., who took only 10 sittings and showed very little
readjustment, made much smaller errors, and these were quickly
eliminated.
The main indication, however, that the transfer effect is not
great in this test comes from comparison with the results of an
unpracticed group. Nine students who had heard of the glasses
but had never worn them before, were given the same test at the
study table but this time with four objects instead of five. From
the results in Table XII, p. 81, we might at first glance conclude
that the regularly larger errors are due to lack of practice with
the glasses. But in the first place it is seen that there is the same
decrease with successive trials as in the practiced group, and the
THE DEVELOPMENT OF A NEW SPATIAL CO-ORDINATION 81
TABLE XI
Initial Errors to Right in Centimeters for Specificity Test at Study Table.
No Screen, Quick Reaction.
Group
Subject
Objects
Number Average
of Total
Sittings Rem.
i
2
3
4
5
Standard
0. B. B.
9
10
ii
14
22
9-5
W. A. 0.
4
4
5
27
3-5
Auditory
C. W. L.
16
12
12
0
4
45
4.2
F.B.
6
3
0
0
10
25
i-3
K. E. L.
9
13
9
7
4
3i
3-8
C. S.
0
0
0
o
0
25
.2
M. M.
14
10
8
10
2
40
3-6
Visual
M. C.
3
4
2
7
3
10
4-5
F. D.
7
9
4
2
6
ii
•5
D. B.
6
6
4
3
3
13
2.0
M. B.
2
2
4
2
3
10
.2
F.
15
2
2
I
0
10
•9 6
M. K.
ii
12
7
2
18
10
18.0
T. L. W.
15
7
12
7
3
18
i-4
R. D.
8
3
6
5
7
IO
10.2
Tactual
J. L. B.
13
15
16
12
19
17
1.4
P. J. R.
7
4
3
4
9
IO
2.3
H. G.
ii
3
2
3
4
IO
.2
A. D. U.
9
6
4
4
2
12
.2
E. B.
5
20
4
7
7
•5
P. I.
3
7
0
4
12
7
1. 1
J. H. B.
2
13
7
i
6
5
•45
M. P.
4
4
8
0
0
6
4
Tactual-
T. K.
ii
12
ii
9
IO
i -7
Kinaesthetic
W. S.
IO
12
13
7
16
IO
.76
M. My.
12
4
4
13
14
IO
47
TABLE XII
Errors to Right in Specificity Test. No Screen. Quick Reaction.
Unpracticed Group.
Objects
Subject
1
2
3
4
E
14.0
21.0
5-0
12.0
W
12.0
4.0
2.0
6.0
F
9.0
3-0
2.0
9.0
FI
15.0
12.5
0.0
8.0
R
12.0
13.0
7-5
II-5
Fr
14.0
16.0
0.0
3-0
H
12.0
3-0
11.0
B
12.0
11.0
2.0
4.0
S
18.0
12.0
4-5
16.0
Average
13-3
10.4
2.9
8.9
82
MARGARET WOOSTER
same individual variation. In the second place it is true that the
experimenter with the unpracticed group took more pains to
impress on the subjects the point that they were not to correct
to the left. In the third place the errors, even though relatively
larger than for the practiced group, are still on the average half
or less than half what the objective uncorrected error would
have been.
It follows then that our second plan for securing a fair measure
of the transfer effect was unsuccessful, and that so far there is no
clear evidence that the new habit functions in every-day situa¬
tions.
A third plan was tried after the regular series had been con¬
cluded. The experience of the writer, M. W., pointed to a possible
source of error in the fact that a more rapid rate of movement
was prescribed for the test than the natural rate employed during
the original building-up of the habit at the apparatus. M. W.
did not complete her readjustment and take the tests with ob¬
jects at the study table until after practically all the other subjects
had finished. She found then that when she reached out very
quickly to localize the objects, she missed them on the average by
as much as iy cm. But when later she tried reaching out at a
natural rate of movement she missed them, if at all, by only one
or two centimeters ! The same results were obtained at several later
times. This suggested that the other subjects may have been
making more than their natural amount of error, since the di¬
rections had been explicit to move very quickly. Such a con¬
clusion is in line with the work of Woodworth on movement.
He found that a simple movement automatically performed at
a natural rate, was made with much less accuracy when the rate
was greatly increased.1
It seemed likely, then, that our test of the generality of the
new coordination had not been a fair one. An attempt was made
to check the accuracy of this conclusion by giving the test in
a modified form to four students who had formerly served as
subjects and had attained varying per cents of readjustment.
1 Woodsworth, R. S. “Le Mouvement.” Paris, 1903. Ch. XV.
THE DEVELOPMENT OF A NEW SPATIAL CO-ORDINATION 83
First, wearing the glasses, they practiced making localizations
at the apparatus, with sight of the finger, until a test given by the
experimenter showed that they could localize the buzzers with
a constant error of less than one centimeter to the right. (Since
readjustment takes place very rapidly in the sight series, and
since the four subjects reached out as often and for as long a
practice period as they pleased, it only required from one to
four sittings to make complete readjustment again.) The sub¬
jects were then given the tests with objects at the study table,
this time with two changes. First, they reached out at a natural
and not a forced rate of movement. Second, the movement of
the hand and arm in reaching was carefully screened by a card¬
board cover so that the finger was seen only when the reaching
movement was concluded. The last precaution was observed to
aid in obviating the incentive to correction afforded by the sight
of the arm.
The results as given in Table XIII are from too few subjects
to justify definite conclusions. While it is worthy of note that
none of the errors are significantly larger than in the preceding
test, there is still no evidence on the basis of results for these
four subjects that the additional precautions taken (of using the
TABLE XIII
Specificity Test
At Study Table — with Cardboard Screen — Natural Rate of Movement.
Per cent Per Cent
Approximate
Subject
Readj. Readj.
Errors
in Cm.
to R. of Objects
Original With Practice
1
2
3
4
T. L. W.
100 100
7
6
5
K. E. L.
10 100
5
3
3
2
H. L. K.
40 100
7
0
9
6
E. S. R.
53 100
12
14
13
11
Average
7-7
5.61
7-8
6.0
Average Error
in Cm. for Objects
Group
No. Subjects
1
2
3
4
With Screen
9
18.0
230
10.6
174
Without Screen
9
130
10.4
2.9
8.9
84
MARGARET WOOSTER
screen and adopting a natural rate of movement) affected the
results.2
TABLE XIV
Specificity Test at Study Table, with Cardboard Screen. Natural Rate of
Movement. Unpracticed Subjects.
Subject
1
Error to Right in Cm.
2 3
4
G. C.
20
24
15
L. M.
26
25
16
22
G. K.
18
20
13
14
R. W.
17
16
7
13
W. B.
19
24
7
21
H. C.
28
28
16
21
N. G.
26
22
16
16
E. B.
22
25
12
1 7
R.L.
7
21
9
18
Average
18.1
22.8
10.6
17.4
Comparison of the results of this modified test with practiced
subjects with results of the same test given to nine unpracticed
subjects does seem, however, to reveal significant differences.
Table XIV gives the individual results.
On the face of it these results would indicate that the larger
amount of error — over twice as great as for the practiced sub¬
jects — must be correlated with lack of practice, and hence that
there is evidence of decided transfer of the space habit to the
study table situation. Again, however, the experimenter here
took special care to instruct the unpracticed subjects not to cor¬
rect to the left, but to locate the objects as they appeared to be —
a care not exercised in the same degree with the practiced sub¬
jects. This source of error alone may possibly account for the
difference in the results. We may say, however, that this situa¬
tion does furnish some evidence, though of doubtful value, for
transfer.
It is not surprising that if we were unable to get conclusive evi¬
dence for transfer to ordinary situations from the test with objects
2 That the use of the screen does help to obviate the tendency to correct
is, however, shown in a comparison of the results of larger groups of un¬
practiced subjects, who were later given short tests at the study table. The
results are as follows:
Average Error in Cm. for Objects:
Group No. Subjects 1234
With Screen 9 18.0 23.0 10.6 17.4
Without Screen 9 13.0 10.4 2.9 8.q
THE DEVELOPMENT OF A NEW SPATIAL CO-ORDINATION 85
at the study table, we were similarly unable to observe any clear
differences in the behavior of practiced and unpracticed subjects
while walking about the room. Both practiced and unpracticed
subjects managed to walk about and perform ordinary acts with
no serious mishaps. In general for both there was a constant
tendency to walk to the right and to reach out to the right of the
actual position of objects. The greater the distance and the
quicker the movement the greater were the errors. Errors in
reaching were also much greater when the movement of the
hand was not seen. There was for most subjects swaying and un¬
steadiness in walking, as long as visual guidance was employed,
and general hesitation and confusion in movement. Some sub¬
jects made much greater errors to the right in reaching for ob¬
jects than others; but among the ten unpracticed subjects thus
observed, the errors varied in extent practically as much as with
practiced subjects.
We might conclude that these observations indicate that there
is no transfer to everyday situations. Two considerations, how¬
ever, show that this conclusion would not be justified. In the
first place, unpracticed subjects in these everyday situations are
under the influence of very powerful sensory incentives to im¬
mediate readjustment. If the mere visual perception of amount
of error, as in Series D, is a strong incentive, how very much
stronger will be the perception of the discrepancy in the total
sensory situation ! In the second place even were an actual transfer
effect present in the case of practiced subjects, it might be obscured
by the operation of other factors. For instance, subjects who had
readjusted to the spatial situation, as far as direction was con¬
cerned, might still be unable to judge distance correctly. The
writer found that many of her errors were made in estimating
depth and distance, not direction. For instance, it was very dif¬
ficult to walk downstairs with visual guidance, not because of any
temptation to go to the right, but because the steps looked curved
and much lower than they actually were, and there was con¬
sequently an inappropriate muscular reaction.
Much of the uncertainty of the practiced subjects may have
been due, then, to this difficulty in adjustment to changed dis-
86
MARGARET WOOSTER
tance relations. Other disturbing factors are the limiting of the
field of vision by the frame of the glasses, and the fact that the
stationary prisms in front of the moving eyes produced dizziness
and, with a few subjects, even nausea.
But while our observation of the general behavior of the sub¬
jects in ordinary situations offers no clear negative evidence on
the question of the general nature of the new space habit, neither
does it offer positive evidence.
While in general it seems that transfer to ordinary situations
is slight, if existent at all, there is evidence that there are indi¬
vidual differences in the matter. Some subjects consistently made
large errors both at the study table and in walking about the
room, while others made negligible errors, or none.
Subject C. S. of the Auditory Series is one for whom the new
habit seemed to carry over effectively into ordinary situations.
She had learned to localize the buzzers without error at the ap¬
paratus in 25 sittings. At the study table she reached out with per¬
fect ease for the objects, making absolutely no error even on the
first trial. (See Table XI). Considering the limitation of the
visual field by the glasses, she made her way about the room with
ease, making no mistakes in direction.
Subjects M. B. of the Visual Series, with ten sittings, may also
possibly have retained the effects of practice in normal situations.
Her errors at the study table were all small (the first being only
4 cm.) and soon disappeared. M. B. found it “perfectly easy to
get around the room and see objects.” She walked about con¬
fidently, picking up objects here and there and reaching out for
door knobs and the like without any observable sign of a tendency
to go to the right. She reported that things looked natural to her,
and that when she reached out to touch things they “seemed in
the right position.” She said she felt no muscular strain or “pull”
away from objects, as most other subjects did.
No subjects in the practiced group were able to adapt them¬
selves so well to ordinary situations as M. B. and C. S. It must
be remembered, however, that these two are exceptions in the
practiced group, and that others in that group constantly made
large errors in direction. In the case of subject E. B. of the
Visual Series, for instance, the new habit seemed to hold only
THE DEVELOPMENT OF A NEW SPATIAL CO-ORDINATION 87
for very specific situations. E. B. had made a readjustment of 97
per cent in seven sittings. After taking the trials for visual ac¬
curacy without glasses at the end of the series, she found that
when she began localizing with glasses again she made just as
large an error to the right as at the beginning! It took 30 trials
to bring her up again to her newly acquired standard of correct
localization. Again when seated at the study table she missed the
first object by 20 cm. but the error quickly decreased in the fol¬
lowing trials. In walking about the room with the glasses on she
again experienced great difficulty, making large errors constantly
unless she went very slowly and caleulatingly.
The writer, when she had finally attained complete readjust¬
ment after 63 sittings, found great difficulty in walking about
the room and down the hall. Unless she disregarded the looks of
things and trusted to the established kinaesthetic-tactual habits,
she made constant errors to the right when distances of several
feet were invloved, as for instance, in walking rapidly to a door
knob from the middle of the room. In walking down a long hall
she bumped into the right wall every few feet unless she used
her right arm as guide. But within more definitely prescribed
areas her errors were much smaller. In fact as long as she used
a natural rate of movement and looked carefully at the objects
she was reaching for, she made either very small errors or none
at all. Her very large errors at the study table (15 to 28 cm.)
were evidently due to the disturbing effect of an unnatural rate
of speed, for when she reached out at a natural rate, even with
the movement of her arm screened, she localized the objects al¬
most perfectly even on the first trial. In general whenever she
moved about the room naturally, without thinking particularly
what she was doing, she found herself able to localize correctly
almost any object she wished to touch. She found on trial that she
was able to- serve herself at the table without difficulty, reach for
the salt, put sugar into her coffee, etc., without any false move¬
ments. It was only when she moved very quickly, or approached
objects quickly from some distance, that serious errors to the
right were made.
The conclusion is that in M. W’s case the new habit probably
88
MARGARET WOOSTER
functioned to a considerable extent in normal situations as long
as the general kinaesthetic setting was the same as prevailed
while the new coordination was forming. The very small errors
which did appear were easily and unconsciously overcome in the
making of practical adjustments. But when large distances were
involved the error, being proportionately greater, would inevita¬
bly be sufficiently large to interfere with practical accuracy,
even though there was a transfer effect. The general confusion,
hesitation, and slight dizziness can be accounted for on the basis
of other disturbing factors previously mentioned.
None of the unpracticed subjects were able, judging from ap¬
pearances, to localize objects with the ease and naturalness of
M. W., and certainly not with the ease of C. S. and M. B. More¬
over the unpracticed subjects were unanimous in reporting a de¬
cided “pull” or muscular conflict while some of the practiced sub¬
jects, among them the three just named, felt no such muscular
strain. For the writer, accurate reaching movements were made
with absolutely no feeling of strain or effort.
We may conclude that for some subjects at least there is evi¬
dence that the newly acquired habit of judging direction in visual
space does function in normal situations. It proved impossible to
isolate the various factors involved sufficiently well at the study
table to test out accurately the transfer effect there, yet there
is some evidence for it even from those tests. More accurate
methods are needed and could no doubt be devised.
The consideration of individual cases, however, both at the
study table and in more general situations, indicates plainly first
that there may be a pronounced carrying over of the habit in
the case of some subjects; second that a slight transfer effect
probably exists for some subjects but is obscured by other dis¬
turbing factors; and third that there are probably marked in¬
dividual differences in the extent to which the new habit is gen¬
eralized.
The general conclusion from all the experiments on specificity
is that the new space habit is by no means a merely limited and
specific mode of functioning, but that it may affect reactions
in more general conditions than those prevailing in the original
THE DEVELOPMENT OF A NEW SPATIAL CO-ORDINATION bg
experiment. The wider significance of this fact is contained in
the statement that the systems of retinal and general kinaesthetic
habits involved in the new spatial coordination apparently func¬
tion to a greater or less degree in general situations. This con¬
clusion must be put forward very tentatively, owing to the un¬
satisfactory nature of the general experimental control.
It is clear, moreover, that the amount of transfer is for most
subjects not very marked. In view of the fact that the glasses
were worn but a short time, we would not expect the system
of habits acquired during that time to have much influence on
the old system of retinal-motor habits which has been functioning
since infancy. The surprising thing is that there is any inter¬
ference at all. Considering the conditions of the experiment we
have here a remarkably stable and well organized habit system,
which functions automatically while the glasses are worn and
even carries over to some extent into the established reaction
system.
Incidentally it is interesting to note that the new reaction pat¬
tern did not disintegrate between trials, but carried over in full
strength from one day’s sitting to the next, in spite of the con¬
flicting modes of adjustment employed meantime. Thus we have
two distinct sets of complex retinal-motor habits, alternating
at short or long intervals according to the stimulating situation
(whether the glasses are worn or not). This fact is suggestive
in connection with the phenomena of alternating personality, in
which the same principles operate though on a vastly more com¬
plex scale.
VI
RELATION OF READJUSTMENT TO DEFINITE
LOCALIZING ACTIVITY
A complete study of the process of the formation of a new
spatial coordination would involve an examination of its relation
to overt motor activity. Is readjustment conditioned by active
efforts to make some definite motor adjustments to the new
90
MARGARET WOOSTER
situation, or may it occur when the subject takes a merely pas¬
sive attitude?
It was our original plan systematically to investigate this as¬
pect of the problem. This we could do by giving only one trial
per sitting for one group of subjects, and comparing the results
with those of groups having, let us say, 20, 40, and 80 trials per
sitting. It would be desirable also to devise a method of response
by verbal identification instead of active reaching. We did not
have time to carry out this plan.
It was thought, however, that some light might be thrown on
the problem (especially in so far as it concerns reasons for read¬
justment in the standard series) by finding out whether or not
any readjustment would occur while the subjects merely sat
passively without making any overt response at all. It was not
practicable to use the apparatus for this purpose, and so with
the four subjects used the procedure was as follows :
The subject, wearing the prismatic glasses, was first given a
test at the apparatus, to determine his average linear deviation
for each of the four buzzers. He reacted by movement of arm
and hand as in preceding series. Three trials were taken for each
position.
The subject was then seated at a table in another room. After
the glasses were put on he remained there passively for 20 min¬
utes, viewing objects in the room, but making no' overt localizing
movements of any kind. Ten such sittings were given. At the close
of the tenth, the subject was again seated at the apparatus, and
the amount of deviation determined as before.
The results are given in Table XV. A number showing positive
increase is preceded by a plus sign and one showing regression
by a minus sign. Three of the four subjects show absolutely no
decrease in deviation after the ten “passive” sittings. One made
an average increase of two cm., but this increase occurred for
only two of the buzzers. On the average, there was even a slight
regression from the actual position of the buzzers.
There were too few cases, and too small a number of trials
in each case, to justify sweeping conclusions. Moreover had
the sittings been taken at the regular apparatus, and had they
been continued longer, the results would have been more con-
THE DEVELOPMENT OF A NEW SPATIAL CO-ORDINATION 91
elusive. They do, however, indicate clearly that under these par¬
ticular conditions no significant readjustment occurs without
definite localizing movements. We may say provisionally, then,
that apparently the process of readjustment to the new spatial
situation is conditioned by definite and overt adaptive movements
on the part of the subjects.
TABLE XV
Difference between Initial and Final Localizations
Subject
53
66
79
92
Av.
C. J. W.
+2.0
—5-o
—3-3
+ -5
—1-5
0. W.
+1.6
— 2.2
+ 1.0
— .8
— 1.0
A. O. U.
+ -6
.0
+4-6
+3-3
+2.1
J. S.
— 7
—4.9
—1.4
— -9
—i-5
VII
SUMMARY AND CONCLUSIONS
The outcome and signficance of our experiments may be sum¬
marized under twelve main heads as follows :
1. No readjustment to the changed visual situation occurred
without definite reaching movements of the hand while the eye
was fixed on the visual object. Thus the development of the new
coordination seems to be conditioned by definite localizing activity
on the part of the subject. The process of forming the new habit
seems to consist largely in the association of visual and tactual
stimuli with kinaesthetic stimuli involved in the localizing move¬
ments. This observation is entirely in accord with Stratton’s
experience. “It was repeatedly noticed in the course of the ex¬
periment”, he says, “that the total experience was much more
harmonious during active movements of my body than when I
inactively looked upon the scene.” And again “The scene it¬
self became more my own by acting upon it, and this action
reacted to bring the representation of my body into harmonious
relation to the scene.”
2. There was a progressive readjustment in the standard
92
MARGARET WOOSTER
series, although there were apparently no sensory stimuli indi¬
cating the actual position of the object. This seems to represent
an unconscious adaptation of the reaching movements to the
new kinaesthetic stimuli from the eye muscles. In other words,
pare of the readjustment that occurred was not a reorgani¬
zation of response with respect to the actual position of the
object, but represented an adaptation to particular sensory con¬
ditions induced by the wearing of the prisms. It is reasonable
to suppose that the readjustment in the standard series was due
to the tendency of the subject mechanically to react with the
hand in response to the old habitual concept of “front” associated
with head position, rather than to the new definition of “front”
involved in the altered position of the eyes in the head. If so,
this would indicate that when there is even a slight disturbance
of the customary relationship between ocular-motor habits and
general bodily habits, the individual mechanically and uncon¬
sciously varies his reactions in such a way as to bring the latter
into harmony with the established type of reaction. In any case
it seems that slight changes in the delicate muscular mechanism
regulating the eye may profoundly influence the overt reactions
of an individual although he may be entirely unaware of the effect
on his behavior of the new kinaesthetic stimuli.
Experimental verification and further investigation of this hy¬
pothesis are needed. While the existence of this hypothetical
ocular-motor stimulus to progressive readjustment has presum¬
ably interfered with the quantitative accuracy of our measure¬
ments of the relative efficacy of various sensory factors, yet its
existence as a conditioning factor, if well established, would
still be profoundly significant. For it would indicate anew, in a
striking way, the extreme intricacy and delicacy of the com¬
plex system of retinal and general habits which, developing and
functioning automatically, constitutes our spatial experience.
3. Subjects in the auditory series in which the sound offered
a sensory clue to the actual position of the subject, showed on
the average no stronger tendency to react closer to that actual
position than those in the standard series. There may be individual
cases in which sound was effective but on the whole the conclusion
THE DEVELOPMENT OF A NEW SPATIAL CO-ORDINATION 93
is justified that under the conditions of our experiment sound
is not an effective factor in the formation of the new spatial
coordination.
4. When contact was used as a practical check on the efficacy
of the localizing movement, a new habit of localization, ob¬
jectively correct, was very rapidly built up. Such a new coor¬
dination is formed on the basis of mere chance contact, but there
was no regular and systematic learning until the subject was
allowed each time to check the accuracy of his reaching movement
by definite exploratory contact with the buzzer. The combined
factors of kinaesthesis and contact then proved to be very
important in the formation of the new coordination.
5. Visual perception of the amount of error served as the
most powerful single sensory factor in the development of the
new habit. The evidence is conclusive that in our experiment
vision was at least as efficacious as the combined tactual and
kinaesthetic factors involved in active touch; and there is good
evidence that it is definitely a more efficacious factor. In this
regard our experiments strongly support a tentative hazard of
Stratton’s for which he was, on the basis of his experiment, un¬
able to adduce direct factual evidence. In discussing the question
as to whether or not visual direction is dependent upon tactual di¬
rection, he says “If there is any dependence either way (which
I doubt) the evidence seems to favor the primacy of sight.” In
his own experiment there are a number of indications that this
is the case. An example is the fact of stubborn persistence of
the “old” localization of parts of the body not visible. Another
is the reference to the old system of the legs in motion while walk¬
ing, if not in the visual field at the tune. Evidently the direct vis¬
ual perception of the amount of error made under the new or
disturbed conditions was for Stratton as for our subjects an ex¬
ceedingly powerful sensory stimulus to new adaptive reactions.
The conclusion is strongly suggested that if it had been possible
to isolate the contact factor, studying its effect apart from the
kinaesthetic stimuli involved in the exploratory movements the
“primacy of sight” would have been far more strikingly demon¬
strated.
94
MARGARET WOOSTER
6. By far the most rapid acquisition of the new coordination
occurred in the tactual-kinaesthetic series, in which the sensory
clues to the tactual position of the object (left finger in this case)
consisted in a whole system of tactual and kinaesthetic impulses
coming from the left arm. We would expect such a wealth of
sensory impulses, intimately concerned as they are in so many
everyday habitual coordinations, to serve as exceptionally strong
stimuli to readjustment for the same reason that we expect the
human infant to learn more easily and quickly to localize parts of
his own body than external objects. Strange to say, however, of
the six subjects in this group only three reacted rapidly to this
effective complex of stimuli. The other three were absolutely un¬
influenced by the stimuli from their own bodies. One was at the
conclusion of the series in absolute ignorance of even the ap¬
proximate position of his unseen localizing hand ! Thus there
are evidently striking individual differences in the extent to
which the development of a new spatial habit may be conditioned
by stimuli from bodily position.
7. The new spatial coordination formed under the conditions
of our experiment was retained for long periods of time, func¬
tioning at a considerable per cent of its effectiveness even after
a lapse of from one to two years. This is in line with experiments
on the retention of other bodily habits, and is one among other
indications that the learning process involved in the acquisition
of the new habit is of a sensory-motor character.
8. The new coordination is not merely specific for the par¬
ticular conditions of its formation, but maintains itself when the
experimental conditions are changed. It even in some cases shows
a transitory influence on reactions to ordinary objects after the
glasses are removed. This shows that with our type of experiment
it is possible to study quantitatively the process of discarding an
acquired spatial habit-system. Stratton found that after the re¬
moval of his glasses his localization of ordinary objects was in¬
terfered with, there being now a tendency to make the opposite
type of error, but he was unable of course to gather quantitative
data on the extent of the interference.
9. The new space habit seems clearly, for some individuals,
THE DEVELOPMENT OF A NEW SPATIAL CO-ORDINATION 95
to function in general everyday situations. This conclusion is of
practical significance in indicating that this type of experiment
may be useful in investigating the question of degree of general¬
ization in the acquisition of spatial habits.
10. There are striking individual differences in the extent to
which various sensory factors contribute to the formation of the
new spatial coordination, in the time required for its development,
and in its strength and stability once acquired. For most sub¬
jects tactual and kinaesthetic factors are very efficacious, but for
some they have apparently no influence at all. Vision is effective
for all our subjects, but in different degrees. Hearing seems
possibly to be efficacious for some, but is unquestionably not an
influential factor for others. For some the new coordination is
easily disturbed, for others not.
Such considerations as these point emphatically to the need for
extensive quantitative investigation of the whole subject of the
acquisition of spatial reactions. It seems quite likely that much of
the disagreement concerning pathological cases as well as normal
reactions in the genesis of spatial experience for individuals may
be due to a failure to consider the possibility of wide individual
differences in the matter.
11. There is no evidence from these experiments that the new
coordination was formed on any other than a purely sensory-
motor basis. At first it was thought that knowledge of the nature
of the error might be a factor making for readjustment, but the
control experiments without knowledge disproved this hypothesis.
The later experiments abundantly bore out this conclusion. While
such factors as interest, conscious shifting of attention, emo¬
tional attitude and the like undoubtedly influenced the type and
rate of progress of the readjustment or learning at various points,
most of it occurred on a purely mechanical or automatic level,
while the subject was entirely unaware of the nature of his re¬
actions. Even in the visual and tactual series the subject was
aware only of the end results of his reactions, which were in no
case, according to the reports of the subjects, under ideational
guidance or control.
12. Perhaps the most significant result of this investigation
q6
MARGARET WOOSTER
is the demonstration that it is possible to secure accurate and
extensive quantitative data on the problem of the factors in the
development of space perception, through the use of relatively
simple experimental procedure. We are keenly aware of many
defects both in apparatus and in procedure. In the course of
the experimenting, however, we have seen ways of obviating
these defects which promise much in the way of future investiga¬
tion of the problem.