31 
 
I ^Vl/ 
 
 57 
 
 tr.^ 
 
UNITED STATES PUBLIC HEALTH SERVICE 
 
 RUPERT BLUE, Surgeon General 
 
 MEMORY TESTS OF SCHOOL CHILDREN 
 
 MEMORY SPAN OF 1,585 WHITE SCHOOL CHILDREN 
 (751 BOYS, 834 GIRLS) IN THE CITY OF X 
 
 BY 
 
 ■ C. W. STILES 
 
 Professor of Zoology 
 United States Public Health Service 
 
 L 
 
 REPRINT No. 316 
 
 FROM THE 
 
 PUBLIC HEALTH REPORTS 
 
 December 24, 1915 
 Pages 3738-3745 
 
 WASHINGTON 
 
 GOVERNMENT PRINTING OFFICE 
 
 1916 
 
 Monograph 
 
D. of D. 
 nB 19 1916 
 
MEMORY TESTS OF SCHOOL CHILDREN.^ 
 
 MEMORY SPAN OF 1,585 WHITE SCHOOL CHttDREN (751 BOYS, 834 GIRLS) IN THE 
 
 CITY OF X.i 
 
 By C. W. Stiles, Professor of Zoology, United States Public Health Sen-ice. 
 
 Of the 1,585 children (751 boys, 834 girls) for whom memory-span 
 data are available, 1,223 (586 boys, 637 girls) belong to group S 
 (from homes provided with sewer connection, but without privies), 
 271 (106 boys, 165 girls) belong to group P (from homes with privy 
 sanitation), and 91 (59 boys, 32 girls) to group U (from homes of 
 unknown sanitation). 
 
 In taking the memory span the following table was used : 
 
 Table 1. — Strong's memory-span numbers.^ 
 
 3 years old: 2 numbers: 7-2 
 
 1-6 
 8-1 
 
 4 years old: 3 numbers: 7-4-8 
 
 2-9-4 
 
 6-3-7 
 6 years old: 4 numbers: 5-1-8-3 
 
 9-2-7-4 
 
 5-9-2-6 
 8 years old: 5 numbers: 4-7-3-9-5 
 
 7-4-2-8-1 
 
 5-8-3-7-6 
 10 years old: 6 niimbers: 8-5-4-7-2-6 
 
 2-7-4-6-5-1 
 
 9-4-1-7-3-8 
 12 years old: 7 numbers: 2-9-6-4-3-7-5 
 
 9-2-8-.5-1-6-4 
 
 1-3-9-5-8-4-7 
 
 8 numbers: 4-7-2-9-3-8-1-5 
 
 7-1-8-3-6-2-9-5 
 4-6-1-5-8-2-9-7 
 
 9 numbers: 9-2-4-7-3-8-6-1-5 
 
 4-7-5-2-9-6-3-1-8 
 9-5-8-3-7-2-6-4-1 
 10 numbers: 8-3-9-5-1-6-2-7-0-4 
 2-1-4-6-0-7-3-8-5-9 
 4-0-5-2-8-1-7-9-6-3 
 
 1 Reprint from the Public HeaUh Reports, vol. 30, No. 52, Dec. 24, 1915, pp. 3738-3745. For other 
 articles on the city of X see Public Health Reports, 1915, as follows: Difficulties in obtaining ages, v. 
 30(5), Jan. 29, pp. 310-311; Zooparasitic intestinal infections, v. 30(27), July 2, pp. 1991-2002; School 
 grades, V. 30(28), July 9, pp. 2060-2067; Tobacco and snufl, v. 30(40), Oct. 1, pp. 2926-2928; Heights and 
 weights of children, v. 30(41), Oct. 8, pp. 2990-3003; I-ung capacity, v. 30(42), Oct. 15, pp. 3067-3072. 
 
 2 Prepared by E. K. Strong, jr., professor of psychology, George Peabody College for Teachers, Nashville, 
 Tenn. 
 
 21096—16 e q 
 
4 MEMORY TESTS OF SCHOOL CHILDEEN. 
 
 Method of giving the memory span. — In giving the memory-span 
 test, we followed the method used by psychologists and psychia- 
 trists. The test was explained to each child separately. The 
 tester would then begin with the first line of the foregoing table and 
 repeat deliberately and in a monotone: "Seven [very short pause], 
 two." If the child failed to repeat these numbei-s in the order 
 given, he was granted a second chance on the next line: "One, six." 
 If he failed on this, he was given a third chance on the third line: 
 *' Eight, four." Not* more than three chances were given on any 
 one series of (2, 3, 4, 5, — x) numbers. As soon as a child repeated 
 the 2, 3, 4, or x numbers in any series, he was tested on the next 
 higher series. (It will be noticed that one extra number is added 
 in each series. See foregoing table.) This was continued until the 
 pupil failed three times on a group. He was accredited with the 
 highest number of figures he could repeat without error. The tests 
 were given by local substitute school teachers, who were, of course, 
 given preliminary practice. 
 
 As I have seen this test given by other investigators, two different 
 ''stage settings" have been used. Some investigators have the 
 "subject" in a room that is perfectly quiet and free from distraction 
 (other than the distraction of isolation); others have the "subject" 
 in a room that is not necessarily perfectly quiet and in which there 
 is or may be some distraction in the way of noise or movement. 
 There are certain arguments in favor of both methods. 
 
 In our tests separate rooms were impossible, even if desirable. 
 Tlie tests were made in a very large school assembly hall and the 
 substitute school teachers were placed at intervals around the room. 
 
 The pupils passed from one teacher to another for certain different 
 mental and physical tests. The confusion was about equal to that 
 found in the average classroom of a weU-regulated Southern school. 
 In other words, the children were tested under conditions that cor- 
 responded as closely as possible to their daily school life. Most of 
 the children looked upon the tests in the light of playing games; 
 some of the pupils were not so thorouglily at their ease. 
 
 That some children did better work with this "stage setting" 
 than they would have done if entirely isolated from the other children 
 seems practically certain; that the reverse holds for other children 
 is equally certain. For instance, a certain girl gave a memory 
 span of 8 numbers; personally, I tested this same girl at her home 
 on several occasions, and she repeatedly showed a memory span of 
 9 and 10 numbers. 
 
 The personal equation, as to nervousness, diffidence, etc., can not 
 be entirely eliminated, but the results obtained show what can be 
 reasonably expected of city school children (white) in the locality in 
 question and with the "stage setting" that was used. 
 
MEMORY TESTS OP SCHOOL CHILDREN. 
 
 Table 2. — Memory span of 751 boys, 6 to 17.75 years old, inclusive, of the city of X, 
 summarized by quarter-year periods, total-year periods, and sanitary groups. 
 
 [P= children from homes provided with a privy; S= children from homes with sewer connection but with- 
 out a privy; U=home sanitation unknown; T= total of P, S, and U.| 
 
 Age. 
 
 Number in memory span, with num- 
 ber of children attainmg each span. 
 
 Num- 
 ber 
 of 
 pu- 
 pils. 
 
 Memory 
 span. 
 
 3 
 
 4 
 
 5 
 
 6 
 
 7 
 
 8 
 
 9 
 
 10 
 
 11 
 
 To- 
 tal. 
 
 A ver- 
 age. 
 
 6.00 T 
 
 
 1 
 3 
 3 
 
 2 
 
 8 
 
 1 
 
 
 
 
 
 
 
 
 1 
 
 6 
 12 
 10 
 23 
 
 5 
 
 1 
 29 
 17 
 21 
 18 
 17 
 57 
 13 
 
 3 
 73 
 18 
 16 
 23 
 22 
 65 
 12 
 
 2 
 79 
 24 
 22 
 25 
 21 
 76 
 12 
 
 4 
 92 
 23 
 27 
 25 
 22 
 75 
 12 
 10 
 97 
 26 
 25 
 20 
 15 
 60 
 21 
 
 5 
 86 
 17 
 18 
 22 
 13 
 52 
 10 
 
 8 
 
 70 
 15 
 15 
 57 
 13 
 56 
 
 9 
 
 5 
 
 70 
 
 14 
 
 19 
 
 12 
 
 4 
 
 38 
 
 3 
 
 8 
 
 49 
 
 13 
 
 4 
 
 28 
 
 63 
 
 59 
 
 121 
 
 28 
 
 5 
 
 154 
 
 94 
 
 118 
 
 100 
 
 95 
 
 326 
 
 67 
 
 14 
 
 407 
 
 112 
 
 99 
 
 144 
 
 143 
 
 413 
 
 73 
 
 12 
 
 498 
 
 158 
 
 141 
 
 160 
 
 134 
 
 500 
 
 70 
 
 23 
 
 593 
 
 151 
 
 186 
 
 167 
 
 154 
 
 513 
 
 78 
 
 67 
 
 658 
 
 1«76 
 
 163 
 
 128 
 
 97 
 
 397 
 
 136 
 
 31 
 
 564 
 
 109 
 
 128 
 
 155 
 
 91 
 
 354 
 
 73 
 
 56 
 
 483 
 
 97 
 
 104 
 
 187 
 
 93 
 
 385 
 
 58 
 
 38 
 
 481 
 
 93 
 
 139 
 
 89 
 
 30 
 
 269 
 
 23 
 
 59 
 
 351 
 
 91 
 
 4.00 
 4.67 
 5.25 
 5.90 
 5 ''6 
 
 6.25 T 
 
 
 2 
 3 
 2 
 5 
 1 
 1 
 7 
 5 
 6 
 9 
 6 
 21 
 •4 
 1 
 26 
 3 
 3 
 2 
 4 
 9 
 3 
 
 1 
 6 
 2 
 
 7 
 2 
 
 
 
 
 
 
 6.50 T 
 
 
 
 
 
 
 
 6.75 T. 
 
 
 3 
 2 
 1 
 
 1 
 
 1 
 
 
 
 
 6S 
 
 
 
 
 
 6P 
 
 
 
 
 
 5 60 
 
 6U 
 
 
 
 
 
 
 5 00 
 
 6T 
 
 
 9 
 3 
 
 1 
 1 
 2 
 
 3 
 
 4 
 
 7 
 
 9 
 6 
 
 11 
 5 
 6 
 
 23 
 4 
 1 
 
 28 
 9 
 4 
 
 13 
 6 
 
 25 
 5 
 2 
 
 32 
 5 
 
 11 
 5 
 5 
 
 20 
 4 
 2 
 
 26 
 5 
 6 
 
 11 
 4 
 
 17 
 6 
 3 
 
 26 
 7 
 
 10 
 9 
 7 
 
 26 
 6 
 1 
 
 33 
 9 
 6 
 5 
 3 
 
 18 
 3 
 2 
 
 23 
 7 
 2 
 4 
 1 
 
 13 
 1 
 
 3 
 3 
 1 
 3 
 3 
 9 
 1 
 
 1 
 
 
 
 
 5 31 
 
 7.00 T 
 
 
 
 
 
 5 53 
 
 7.25 T 
 
 1 
 
 1 
 
 
 
 
 5 62 
 
 7.50 T 
 
 
 
 
 5 55 
 
 7.75 T 
 
 
 
 
 
 
 5 59 
 
 7S 
 
 
 1 
 
 
 
 
 5 72 
 
 7P 
 
 
 
 
 
 5 15 
 
 7 U 
 
 1 
 1 
 
 
 
 
 
 4 67 
 
 7T 
 
 10 
 5 
 4 
 
 .8 
 9 
 
 22 
 4 
 
 1 
 1 
 3 
 
 • 
 
 
 
 5 57 
 
 8.00 T 
 
 
 
 
 6 22 
 
 8.25 T 
 
 
 2 
 
 
 
 
 6 19 
 
 8.50 T 
 
 
 
 
 
 6 26 
 
 8.75 T .. 
 
 
 
 3 
 
 7 
 
 
 
 
 6 50 
 
 8S 
 
 
 ^ 
 
 
 
 
 6 35 
 
 8P 
 
 
 
 
 
 6.08 
 
 8U 
 
 
 
 
 
 
 
 6 00 
 
 8T 
 
 
 2 
 
 i 
 
 2 
 2 
 
 1 
 5 
 
 12 
 4 
 1 
 5 
 5 
 
 10 
 5 
 
 'is" 
 
 6 
 1 
 1 
 2 
 8 
 1 
 1 
 10 
 3 
 3 
 .... 
 
 6 
 
 1 
 
 "Y 
 
 2 
 
 26 
 
 9 
 
 4 
 
 8 
 
 ■ 5 
 
 22 
 3 
 1 
 
 26 
 6 
 
 17 
 9 
 8 
 
 33 
 3 
 4 
 
 40 
 7 
 8 
 6 
 6 
 
 11 
 
 13 
 3 
 
 27 
 3 
 6 
 9 
 4 
 
 15 
 3 
 4 
 
 22 
 6 
 7 
 
 12 
 6 
 
 23 
 6 
 2 
 
 31 
 1 
 
 10 
 1 
 1 
 7 
 1 
 5 
 
 13 
 3 
 
 7 
 4 
 3 
 4 
 5 
 16 
 
 
 
 
 6 30 
 
 9.00 T 
 
 
 1 
 .... 
 
 
 
 6 58 
 
 9.25 T 
 
 
 1 
 
 
 6 41 
 
 9.50 T.. . . . 
 
 
 6 40 
 
 9.75 T 
 
 
 
 
 6 38 
 
 9.S . . .... 
 
 
 2 
 
 1 
 
 
 6 58 
 
 9 P 
 
 
 5 83 
 
 9 
 
 
 1 
 
 6 
 
 
 
 
 
 5.75 
 
 9T 
 
 
 16 
 5 
 1 
 3 
 
 8 
 13 
 2 
 2 
 17 
 6 
 4 
 3 
 1 
 14 
 
 2 
 1 
 2 
 1 
 
 1 
 
 
 6.45 
 
 10.00 T 
 
 
 6.57 
 
 
 
 
 
 
 6 89 
 
 10.50 T 
 
 
 
 
 
 6 68 
 
 10.75 T. 
 
 
 
 
 
 7 00 
 
 10 S 
 
 
 
 4 
 
 
 
 6 84 
 
 
 
 
 
 
 6.50 
 
 10 U 
 
 
 
 
 
 
 6 70 
 
 10 T 
 
 
 
 4 
 2 
 
 
 
 6.78 
 
 11.00 T 
 
 
 1 
 
 
 
 6.77 
 
 11.25 T 
 
 
 
 
 6 52 
 
 11.50 T 
 
 
 2 
 
 
 
 
 6.40 
 
 
 
 
 
 
 6 47 
 
 US 
 
 
 1 
 1 
 1 
 3 
 
 2 
 
 
 
 6.62 
 
 HP 
 
 
 
 
 6 48 
 
 11 u 
 
 
 
 
 
 
 6.20 
 
 11 T.... . . 
 
 
 14 
 3 
 
 4 
 3 
 2 
 10 
 
 "2 
 12 
 
 "3 
 8 
 5 
 
 13 
 
 2 
 
 
 
 6 56 
 
 12.00 T 
 
 
 
 
 6.41 
 
 12.25 T 
 
 
 
 2 
 2 
 1 
 4 
 1 
 
 
 
 7.11 
 
 12.50 T 
 
 
 
 2 
 2 
 5 
 1 
 
 1 
 
 1 
 
 
 7.05 
 
 12.75 T 
 
 
 
 7.00 
 
 12 S 
 
 
 
 6.81 
 
 
 
 
 2 
 
 
 7 30 
 
 12 U 
 
 
 
 7 00 
 
 12 T 
 
 
 
 6 
 
 "2 
 3 
 
 1 
 4 
 2 
 
 5 
 1 
 
 1 
 
 2 
 
 
 6.90 
 
 13.00 T 
 
 
 1 
 
 6 47 
 
 13.25 T .. 
 
 
 
 
 6 93 
 
 13.50 T 
 
 
 
 
 
 6 93 
 
 13.75 T 
 
 
 
 
 
 
 7.15 
 
 13 S 
 
 
 1 
 
 2 
 
 
 
 6.87 
 
 13 P.... 
 
 
 
 
 6 44 
 
 13 U 
 
 
 
 3 
 
 16 
 4 
 6 
 5 
 1 
 
 11 
 2 
 3 
 
 16 
 1 
 
 
 
 
 7 60 
 
 13 T... . . . 
 
 
 1 
 1 
 
 6 
 1 
 
 1 
 1 
 
 14 
 6 
 1 
 3 
 1 
 
 11 
 
 2 
 
 1 
 
 "i' 
 1 
 3 
 
 
 
 6 87 
 
 14.00 T 
 
 
 
 
 6.64 
 
 
 
 1 
 1 
 
 
 7 32 
 
 14.50 T 
 
 
 
 7.42 
 
 14.75 T.. . .... 
 
 
 
 7.50 
 
 14S 
 
 
 1 
 
 3 
 
 2 
 
 
 7.08 
 
 
 
 7.67 
 
 14 U 
 
 
 
 
 
 
 
 
 7.37 
 
 14 T 
 
 
 1 
 
 3 
 2 
 
 11 
 
 4 
 
 3 
 
 2 
 
 2 
 1 
 
 
 7.16 
 
 15.00 T 
 
 
 7.00 
 
6 MEMORY TESTS OF SCHOOL CHILDREN. 
 
 Table 2. — Memory span of 751 hoys, 6 to 17.75 years old, inclusive, of the city of X, 
 summarized by quarter-year periods, total-year periods, and sanitary groups — Contd. 
 
 / 
 Age. 
 
 Number in memory span, with num- 
 ber of children attainmg each span. 
 
 Num- 
 ber 
 of 
 pu- 
 pils. 
 
 Memory 
 span. 
 
 3 
 
 4 
 
 5 
 
 6 
 
 7 
 
 8 
 
 9 
 
 10 
 
 11 
 
 To- 
 tal. 
 
 Aver- 
 ago. 
 
 15 25T 
 
 
 
 1 
 
 "i' 
 
 4 
 5 
 1 
 3 
 
 9 
 2 
 
 7 
 6 
 6 
 
 IS 
 1 
 3 
 
 22 
 1 
 3 
 7 
 2 
 
 11 
 1 
 2 
 
 14 
 1 
 1 
 2 
 1 
 4 
 1 
 
 5 
 1 
 4 
 9 
 1 
 1 
 11 
 1 
 4 
 5 
 
 "'9' 
 
 1 
 
 5 
 
 
 
 18 
 8 
 
 15 
 
 41 
 4 
 9 
 
 54 
 8 
 8 
 
 17 
 3 
 
 31 
 3 
 2 
 
 36 
 4 
 4 
 5 
 3 
 
 12 
 2 
 2 
 
 16 
 
 139 
 56 
 
 103 
 
 294 
 30 
 6.3 
 
 3S9 
 55 
 62 
 
 127 
 23 
 
 22s 
 25 
 14 
 
 267 
 27 
 33 
 38 
 22 
 92 
 13 
 15 
 
 120 
 
 7.72 
 
 15.50 T 
 
 
 
 
 
 7.00 
 
 15.75 T 
 
 
 
 1 
 4 
 
 
 
 
 6.S7 
 
 15 S 
 
 
 
 
 1 
 
 
 7.17 
 
 15 P 
 
 
 
 7.50 
 
 15 U 
 
 
 
 
 
 
 7.22 
 
 15 T 
 
 
 
 4 
 4 
 
 1 
 
 
 7.20 
 
 16.00 T 
 
 
 
 6. 87 
 
 16.25 T 
 
 
 
 
 
 
 7.75 
 
 16.50 T 
 
 
 
 
 3 
 
 2 
 
 
 7.47 
 
 16.75 T 
 
 
 
 
 7.67 
 
 16 S 
 
 
 
 
 7 
 
 1 
 
 1 
 
 
 7.35 
 
 16 P 
 
 
 
 
 8.33 
 
 16 U 
 
 
 
 
 
 7.00 
 
 16 T 
 
 
 
 
 7 
 2 
 
 10 
 
 1 
 1 
 1 
 
 "'3' 
 
 
 2 
 
 
 7.42 
 
 17.00 T 
 
 
 
 
 6.75 
 
 17.25 T 
 
 
 
 
 
 
 
 8.25 
 
 17.50 T 
 
 ' 
 
 
 
 1 
 1 
 2 
 1 
 
 1 
 4 
 
 1 
 
 
 7.60 
 
 17.75 T 
 
 
 
 
 7.33 
 
 17 S 
 
 
 
 
 1 
 
 
 7.67 
 
 17 P 
 
 
 
 
 6.50 
 
 17U 
 
 
 
 
 
 3 
 
 
 
 7.50 
 
 17T 
 
 
 
 
 5 
 
 3 
 
 1 
 
 
 7.50 
 
 
 
 
 
 
 Table 3. — Memory span of 834 girls, 6 to 17.75 years old, inclusive, of the city of X, 
 summarized by quarter-year periods, total-year periods, and sanitary groups. 
 
 [P= children from homes provided with a privy; S=children from homes with sewer connection but with- 
 out a privy; U=home sanitation unlcnown; T=total of P, S, and V.] 
 
 Age. 
 
 Number in memory span, with num- 
 ber of children attaining each span. 
 
 Num- 
 ber 
 of 
 pu- 
 pils. 
 
 Memory 
 span. 
 
 3 
 
 4 
 
 5 
 
 6 
 
 7 
 
 8 
 
 9 
 
 10 
 
 11 
 
 To- 
 tal. 
 
 -Vver- 
 age. 
 
 6.00 T 
 
 
 
 
 1 
 
 1 
 6 
 2 
 9 
 
 1 
 
 1 
 
 1 
 
 .... 
 
 2 
 1 
 
 
 
 
 
 2 
 10 
 12 
 
 7 
 27 
 
 3 
 
 1 
 31 
 15 
 18 
 15 
 13 
 39 
 16 
 
 6 
 61 
 18 
 11 
 17 
 19 
 46 
 17 
 
 2 
 65 
 19 
 20 
 24 
 15 
 53 
 21 
 
 4 
 78 
 25 
 
 13 
 
 52 
 
 68 
 
 38 
 
 149 
 
 18 
 
 4 
 
 171 
 
 76 
 
 111 
 
 84 
 
 68 
 
 218 
 
 90 
 
 31 
 
 339 
 
 102 
 
 69 
 
 103 
 
 119 
 
 288 
 
 96 
 
 9 
 
 393 
 
 119 
 
 134 
 
 157 
 
 104 
 
 365 
 
 126 
 
 23 
 
 514 
 
 1.58 
 
 6.50 
 
 6.25 T 
 
 
 1 
 
 1 
 
 1 
 
 7 
 4 
 
 
 
 
 
 5.20 
 
 6.50 T 
 
 
 1 
 
 [ 
 
 
 5.67 
 
 6.75 T 
 
 
 
 
 5.43 
 
 6S 
 
 
 2 1.'? 
 
 1 
 
 
 
 
 6.52 
 
 6P 
 
 
 
 1 
 
 
 
 
 6.00 
 
 6U 
 
 
 1 
 
 
 
 
 
 4.00 
 
 6T 
 
 
 3 
 4 
 1 
 1 
 3 
 6 
 2 
 1 
 9 
 4 
 
 14 
 6 
 5 
 6 
 6 
 
 14 
 5 
 4 
 
 23 
 2 
 3 
 4 
 3 
 9 
 2 
 1 
 
 12 
 3 
 1 
 4 
 1 
 3 
 4 
 2 
 9 
 3 
 
 10 
 5 
 6 
 6 
 2 
 
 12 
 7 
 
 "w 
 
 6 
 4 
 9 
 6 
 15 
 10 
 
 3 
 
 1 
 
 
 
 
 5.52 
 
 7.00 T 
 
 
 
 
 
 5.07 
 
 7.25 T 
 
 
 2 
 2 
 2 
 
 4 
 1 
 1 
 6 
 3 
 2 
 3 
 4 
 
 10 
 2 
 
 4 
 
 
 
 
 6.17 
 
 7.50 T 
 
 
 
 
 
 5.60 
 
 7.75 T 
 
 
 
 
 
 
 6.23 
 
 7S 
 
 
 3 
 1 
 
 
 
 
 5.59 
 
 7P 
 
 
 
 
 
 5 62 
 
 7U 
 
 
 
 
 
 5.17 
 
 7T 
 
 
 4 
 2 
 2 
 1 
 4 
 9 
 
 
 
 
 5.56 
 
 8.00 T 
 
 1 
 
 
 
 
 5 67 
 
 8.25 T 
 
 
 
 
 6.27 
 
 8.50 T 
 
 
 
 
 
 
 6.06 
 
 8.75 T 1 
 
 2 
 2 
 3 
 
 1 
 6 
 1 
 
 1 
 
 
 
 
 6.26 
 
 8S 
 
 1 
 
 
 
 
 6 26 
 
 8P 
 
 
 
 
 5.65 
 
 8U 
 
 
 
 
 
 
 4.50 
 
 8T 
 
 1 
 1 
 
 25 
 6 
 5 
 7 
 2 
 
 12 
 7 
 1 
 
 20 
 9 
 
 12 
 3 
 
 10 
 10 
 9 
 24 
 
 7 
 
 1 
 
 32 
 
 8 
 
 9 
 5 
 2 
 2 
 3 
 11 
 1 
 
 
 
 
 6.05 
 
 9.00 T 
 
 
 
 
 6 26 
 
 9.25 T 
 
 1 
 
 1 
 
 
 
 6.70 
 
 9.50 T 
 
 
 
 
 6.54 
 
 9.75T 
 
 
 
 
 
 6.93 
 
 9S 
 
 
 1 
 1 
 
 2 
 
 
 
 6.89 
 
 9P 
 
 1 
 
 
 
 6.00 
 
 9U 
 
 
 
 
 6.75 
 
 9T 
 
 1 
 
 2 
 2 
 
 12 
 2 
 
 2 
 
 1 
 
 
 
 6.59 
 
 lO.OOT 
 
 
 
 6.32 
 
MEMOEY TESTS OF SCHOOL CHILDREN. 
 
 Table 3. — Memory span of 834 girls, 6 to 17.75 years old, inclusive, of the city of X, 
 summarized by quarter-year periods, total-year periods, and sanitary groups — Continued. 
 
 Age. 
 
 Number in memory span, with num- 
 ber of children attaining each span. 
 
 Num- 
 ber 
 of 
 pu- 
 pils. 
 
 Memory 
 span." 
 
 3 
 
 4 
 
 5 
 
 e 
 
 7 
 
 8 
 
 9 
 
 10 
 
 11 
 
 To- 
 tal. 
 
 Aver- 
 age. 
 
 10.25 T 
 
 
 
 2 
 
 7 
 
 2 
 
 13 
 
 1 
 
 8 
 6 
 
 10 
 
 22 
 
 10 
 1 
 
 33 
 9 
 3 
 7 
 4 
 
 17 
 5 
 1 
 
 23 
 3 
 8 
 5 
 7 
 
 17 
 5 
 1 
 
 23 
 
 6 
 
 22 
 6 
 
 2 
 2 
 2 
 6 
 2 
 
 1 
 .... 
 
 1 
 2 
 
 
 
 20 
 24 
 22 
 69 
 21 
 
 1 
 91 
 26 
 12 
 31 
 10 
 60 
 17 
 
 2 
 79 
 14 
 18 
 28 
 17 
 59 
 15 
 
 3 
 77 
 14 
 21 
 31 
 27 
 75 
 15 
 
 3 
 93 
 26 
 19 
 31 
 14 
 66 
 19 
 
 5 
 90 
 22 
 17 
 19 
 13 
 56 
 14 
 
 1 
 71 
 16 
 21 
 19 
 12 
 58 
 
 6 
 
 4 
 68 
 11 
 
 8 
 
 4 
 
 7 
 29 
 
 1 
 
 129 
 150 
 144 
 434 
 141 
 6 
 581 
 170 
 
 S5 
 21s 
 
 71 
 415 
 116 
 
 13 
 544 
 
 99 
 
 lis 
 
 190 
 124 
 403 
 107 
 
 21 
 531 
 
 96 
 156 
 223 
 192 
 540 
 104 
 
 23 
 607 
 177 
 142 
 217 
 101 
 4G9 
 131 
 
 37 
 637 
 159 
 124 
 137 
 
 88 
 406 
 
 96 
 6 
 508 
 113 
 148 
 1.39 
 
 88 
 421 
 
 41 
 
 26 
 488 
 
 87 
 
 61 
 
 34 
 
 49 
 
 223 
 
 8 
 
 
 10.50 T 
 
 
 
 
 6 25 
 
 10.75 T 
 
 
 
 10 S 
 
 
 
 
 
 6.29 
 
 10 P 
 
 
 10 u 
 
 
 
 
 
 6.00 
 6.38 
 6.54 
 7.08 
 7.03 
 7.10 
 6.92 
 6 82 
 
 10 T 
 
 
 
 14 
 2 
 
 28 
 
 10 
 6 
 
 14 
 2 
 
 20 
 
 11 
 1 
 
 32 
 8 
 2 
 9 
 3 
 
 18 
 3 
 1 
 
 22 
 4 
 
 10 
 8 
 8 
 
 28 
 5 
 1 
 
 34 
 7 
 7 
 5 
 3 
 
 18 
 4 
 
 '22' 
 11 
 10 
 8 
 5 
 26 
 7 
 
 8 
 4 
 2 
 
 8 
 1 
 15 
 
 3 
 
 
 
 11.00 T 
 
 
 11.25 T 
 
 
 1 
 1 
 
 1 
 2 
 
 1 
 
 
 
 11.50 T 
 
 
 
 
 
 
 11.75 T 
 
 
 
 
 1 
 
 1 
 
 lis 
 
 
 
 11 P 
 
 
 11 U 
 
 
 
 
 
 
 6.50 
 6.89 
 7.07 
 6. .56 
 6.79 
 7 29 
 
 11 T 
 
 
 
 
 15 
 2 
 4 
 8 
 4 
 
 14 
 3 
 1 
 
 IS 
 8 
 6 
 8 
 9 
 
 19 
 4 
 2 
 
 25 
 5 
 6 
 8 
 6 
 
 20 
 3 
 2 
 
 25 
 7 
 6 
 4 
 1 
 
 16 
 2 
 
 3 
 
 1 
 
 .... 
 
 1 
 
 ""3' 
 
 
 
 12.00 T 
 
 
 12.25 T 
 
 
 
 
 
 
 12.50 T 
 
 
 12.75 T 
 
 
 2 
 3 
 
 
 12 S 
 
 
 
 
 6.83 
 7 13 
 
 12 P 
 
 
 12 U 
 
 
 
 
 
 7 00 
 
 12 T 
 
 
 
 
 3 
 2 
 3 
 3 
 
 1 
 6 
 1 
 
 3 
 
 
 6.90 
 6.86 
 7.43 
 7 19 
 
 13.00 T 
 
 
 13.25 T 
 
 
 
 3 
 6 
 2 
 
 1 
 6 
 5 
 13 
 3 
 
 
 
 13.50 T 
 
 
 
 2 
 1 
 3 
 
 
 13.75 T 
 
 
 
 7 11 
 
 13 S 
 
 
 
 7.20 
 6.93 
 7.67 
 7 17 
 
 13 P 
 
 
 
 13 U 
 
 
 
 
 
 13 T 
 
 
 
 8 
 
 1 
 
 16 
 
 10 
 3 
 
 12 
 3 
 
 19 
 7 
 2 
 
 28 
 4 
 1 
 2 
 2 
 6 
 2 
 1 
 9 
 3 
 4 
 3 
 2 
 7 
 2 
 3 
 
 12 
 2 
 1 
 
 7 
 1 
 
 3 
 3 
 
 1 
 5 
 2 
 1 
 8 
 1 
 
 3 
 
 
 11.00 T 
 
 
 
 6.81 
 7 47 
 
 14.25 T 
 
 
 
 
 14.50 T 
 
 
 
 1 
 
 1 
 2 
 1 
 
 1 
 
 
 7 00 
 
 14.75 T 
 
 
 7 21 
 
 14S .. .. 
 
 
 
 1 
 
 1 
 
 
 7 11 
 
 14 P 
 
 
 6 89 
 
 14 U 
 
 
 7 40 
 
 14 T 
 
 
 
 3 
 
 2 
 
 
 7 08 
 
 15.00 T 
 
 
 7 23 
 
 15.25 T 
 
 
 
 
 
 
 7 29 
 
 15.50 T 
 
 
 
 2 
 2 
 2 
 2 
 
 3 
 
 1 
 4 
 
 1 
 
 
 
 7 21 
 
 15.75 T 
 
 
 
 1 
 1 
 
 
 6.77 
 7 25 
 
 15 S 
 
 
 15P 
 
 
 6 86 
 
 15 U 
 
 
 
 
 
 6 00 
 
 15T 
 
 
 1 
 
 
 33 
 7 
 9 
 8 
 4 
 
 25 
 3 
 
 "28' 
 3 
 2 
 
 1 
 1 
 7 
 
 18 
 4 
 7 
 7 
 6 
 
 22 
 1 
 1 
 
 24 
 1 
 4 
 1 
 2 
 7 
 1 
 
 5 
 1 
 
 1 
 
 
 7 15 
 
 16.00 T 
 
 
 7 06 
 
 16.25 T 
 
 
 
 
 
 7 05 
 
 16.50 T 
 
 
 
 1 
 
 
 
 7.32 
 
 16.75 T 
 
 
 
 
 
 
 7 33 
 
 16 S 
 
 
 
 
 2 
 
 
 
 7.26 
 
 16 P 
 
 
 
 
 
 6 83 
 
 16 U 
 
 
 
 
 
 
 6.50 
 
 
 
 
 
 2 
 4 
 1 
 1 
 1 
 7 
 
 
 
 7 18 
 
 17.00 T 
 
 
 
 1 
 
 
 7.91 
 
 17.25 T 
 
 
 
 
 7.62 
 
 17.50 T 
 
 
 
 
 1 
 
 8 50 
 
 17.75T 
 
 
 
 
 2 
 5 
 
 
 
 7.00 
 
 17S 
 
 
 
 2 
 
 
 7.69 
 
 17 P 
 
 
 
 8.00 
 
 17 U 
 
 
 
 
 
 
 1 
 
 
 
 17 T 
 
 
 
 
 5 
 
 7 
 
 8 
 
 7 2 
 
 
 
 30 
 
 231 
 
 7 70 
 
 
 
 
 
 
 
 Cont'parison hy total-year periods and sex groups. — If the total-year 
 periods be compared (see chart 1), it is seen that there is in general 
 a gradual increase in the memory span from the younger to the older 
 groups. This increase is not, however, regular from year to year, 
 for in the boys the 10-year-old period excelled the 11-year-old period, 
 
8 
 
 MEMORY TESTS OF SCHOOL CHILDEEN. 
 
 and the 12-year-old period excelled the 13-year-old period; among, 
 the girls the 9-year-old period excelled the 10-year-old period, and 
 the 13-year-old period excelled the 14- and 15-year-old periods. 
 
 If the two sex groups (chart 1) for each year be compared, it is 
 seen that neither sex uniformly excelled the other; in 5 total-year 
 periods (6, 9, 11, 13, and 17 years) the girls excelled the boys; and 
 in 6 total-year periods (7, 8, 10, 14, 15, and 16 years) the boys excelled 
 the girls, but the difference in one instance is negligible; the boys 
 and girls were equal, or practically equal, in 2 periods (7 and 12 years). 
 
 The conclusion would therefore seem to be justified that no essential 
 difference was shown between the memory spans of the two sexes, 
 and that while there was in general a gradual increase in the aver- 
 age memory span from younger to older children, this increas3 did 
 not express itself in exact ratio to age. Considering the matter from 
 a standpoint of the average of accomplishment per year in chrono- 
 logical age rather than the average per year in mental age, it would 
 
 Memory Span in Nl/mberj 
 
 Chart -I. 
 FOR 748 kVHiTEBoYS/iND 833 White Girls 6.00 to 17.75 tears old, inclusive,- Co 
 
 tINTY OF X. 
 
 8.OT 
 
 7.OT 
 1 
 
 b Years 
 
 7 Yt«R5 
 
 8 Yeabs 
 
 9YtAB5 
 
 IOYears 
 
 II Years, 
 
 I2YEAB1 
 
 I3YEAR5 
 
 I4YEAR5 
 
 IS Years 
 
 |5Yej>r«, 
 
 I7YEAR5 
 
 
 
 
 
 
 
 
 
 
 
 
 p— s — 
 
 
 1 
 
 1 ^=J 
 
 =3^3-< 
 
 ^^ 
 
 —ii 
 
 f: 
 
 — i — 1 
 
 — * 
 
 
 —^ 
 
 \—t — d 
 — ^ — 
 
 '4 
 
 — s-^^ 
 — iT- 
 
 k°=r — 
 
 r\ 
 
 
 —^ 
 
 
 
 
 
 
 
 EE^E 
 
 V5. Pueuc Health Service 
 
 appear reasonable to expect that the average white child, boy or girl, 
 in the locality in question, and in the ''stage setting" used, will show 
 the following memory spans: 
 
 Numbers. 
 
 Children 6 and 7 years old 5 
 
 Children 8 to 13 years (inclusive) old 6 
 
 Children 14 to 17 years (inclusive) old 7 
 
 Thus the average child of 6, 7, 8, and 9 years (chronological age) 
 exceeded the memory span as given by Strong, and the average child 
 of 12 and 13 years did not attain the memory span as given by 
 Strong. Whether this indicates that Strong's conclusion as to the 
 memory span at different ages should be revised or whether it 
 indicates a precocity of the younger children and a retardation of 
 the older children studied, or a difference of results due to different 
 "stage settings" may be left suh judice. 
 
 Comjmrison of sanitary groups. — In a former article^ it was shown 
 that children from sewered homes advance, on an average, more 
 rapidly in school grades than do the children from homes provided 
 with privies. 
 
 1 Public Health Reports, v. 30 (28), July 9. 1915, pp. 2060-2067. 
 
MEMORY TESTS OF SCHOOL CHILDREN. 9 
 
 If the sanitary groups in the memory-span tabulations are com- 
 pared for the total years (in order to obtain larger groups than are 
 furnished by the quarter-year divisions), it is seen that there are 48 
 sanitary groups (24 ''S" groups, 24 ''P" groups) that can be com- 
 pared. In these 24 comparisons (12 of boys, 12 of girls), 14 S groups 
 (7 of boys, 7 of girls) excel as compared with 10 P groups (5 of boys, 
 5 of girls) that excel; but the S groups are larger than the P groups. 
 
 So far as it is possible to judge, on basis of the 1,585 white children 
 (751 boys, 834 girls) studied, the children from sewered homes aver- 
 age a higher memory span than do the corresponding children from 
 privy homes. It is further worthy of notice that in at least 5 of the 
 P groups that stand higher than the correspondmg S groups the num- 
 ber of children in the P groups is so small (one-ninth or less) as com- 
 pared with the corresponding S groups that the value of the com- 
 parison in these 5 groups is materially reduced." For instance — 
 
 Boys 14 P contains only 3 pupils as compared with 14 S (38 pupils). 
 Boys 15 P contains only 4 pupils as compared with 15 S (41 pupils). 
 Boys 16 P contains only 3 pupils as compared with 16 S (31 pupils). 
 Girls 6 P contains only 3 pupils as compared with 6 S (27 pupils). 
 Girls 17 P contains only 1 pupil as compared with 17 S (29 pupils). 
 
 The same statements made in a former article, in connection Vvdth 
 the grade advancements, hold in connection with the memory spans, 
 namely, that numerous sociological factors come into consideration 
 in this connection and that the sanitation, with its attendant results, 
 is only one of these factors. It is, however, clear that the children 
 from the homes with b tter sanitation actually averaged a higher 
 memory span than did the hildren from homes with poorer sanitation. 
 
 Cases of Intestinal Infections. 
 
 Hookworms. — Of the 83 white p j^jiIs (55 boys, 28 girls) who showed 
 hookworm infection, memory-span results are available for 52 
 (36 boys, 16 girls). Computing these results on basis of the average 
 for the separate sex, total-year, and saiiitary groups, these 52 children 
 were entitled to a total memory span of 343.24 (boys 237.20, girls 
 106.4); they actually made a total of 339 (boys 232, girls 107); thus 
 they showed an average loss of 0.08 (boys 0.14 loss, girls 0.06 gain). 
 
 Ascaris. — Of the 58 pupils (46 boys, 12 girls) who showed Ascans 
 infection, memory-span results are available for 38 (29 boys, 9 girls). 
 Comjjuting these results on basis of the average for the separate sex, 
 total-year, and sanitary groups, these 38 pupils were entitled to a 
 total memory span of 245.23 (boys 187.60, girls 57.63); they actually 
 made a total of 250 (boys 197, girls 53) ; thus they showed an average 
 of 0.13 gain (boys 0.32 gain, ghls 0.51 loss). 
 
 Lamllia. — Of the 99 pupils (71 boys, 28 girls) who showed Lamblia 
 infection, memory-span results are available for 67 (50 boys, 17 girls). 
 
10 MEMORY TESTS OF SCHOOL CHILDEEN. 
 
 Computing these results on basis of the average for the separate sex, 
 total-year, and sanitary groups, these 67 pupils were entitled to a 
 total memory span of 441.36 (boys 325.93, girls 115.43) ; they actually 
 made a total of 444 (boys 331, girls 113) ; thus they showed an average 
 of 0.04 gain (boys 0.10 gain, girls 0.14 loss). 
 
 Endamceha coli. — Of the 68 pupils (46 boys, 22 girls) who showed 
 infection with Endamaha coli, memory-span results are available for 
 55 (39 boys, 16 girls). Computing these results on basis of the 
 average for the separate sex, total-year, and sanitary groups, these 
 55 pupils were entitled to a total memory span of 367.29 (boys 259.31, 
 ghls 107.98); they actually made a total of 376 (boys 266, gnls 110); 
 thus they showed an average gain of 0.15 (boys 0.17, girls 0.13). 
 
 Other 'parasites. — The infections with Trichuris, Trichomonas, and 
 Hymenolepis are too small in number to justify conclusions. 
 
 Conclusions. — The results obtained in pupils with parasitic infec- 
 tions (in general, hght cases) do not show that the known infections 
 with hookworms, eelworms, Lamblia, or Endamoeha coli had any mate- 
 rial influence in inhibiting the average memory span of their respec- 
 tive groups. It should, however, be recalled that only 31.7 per cent of 
 the white pupils submitted specimens for microscopic examination, 
 and we have no way of knowing whether or not intestinal infections 
 were present in the two- thirds who were not examined for intestinal 
 
 parasites. 
 
 Summary. 
 
 White urban school children in the sand district of the South may 
 be reasonably expected to average the following memory spans: 
 6 and 7 years, chronological age, 5 numbers; 8 to 13 years, inclusive, 
 6 numbers; 14 to 17 years, inclusive, 7 numbers. 
 
 The children from homes with better sanitation can reasonably be 
 expected to excel in memory span those from homes with poorer 
 sanitation approximately in the ratio of 14 to 10, calculated on basis 
 of total year periods. 
 
 The evidence at hand does not show that hght infections with 
 hookworms (Necator), eelworms (Ascaris), Lamhlia, or Endamoeha 
 coli had any material effect in inhibiting the memory span of the 
 children who were found to harbor these parasites, when their memory 
 .span was compared with the average of the children of their respec- 
 tive groups. This conclusion can not be extended at present to cases 
 of severer infection with these parasites. 
 
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