178 



SECTIONAL ADDRESSES. 



of one or two years is a further evidence of the sensitivity of this period 

 to environmental influence. 



Most of those psychologists who, unlike Watson, believe that man 

 possesses many innate tendencies, are still uncertain as to what precisely 

 they are. ' We do not know,' says Thorndike, ' what situations originally 

 provoke smiling, laughing, crying, frowning, etc' If the problem is to be 

 answered, it can only be by daily observation of children from birth, and 

 I shall suggest later some answers to this particular query of Thorndike, 

 especially in relation to laughter and imitation. 



A third influence that is proving a powerful stimulant to infant 

 psychology is the attempt to press back the testing of intelligence earlier 

 than three years, the lowest age for which Binet tried to devise tests. The 

 valuable pioneer work done by Dr. Arnold Gesell has provided tests which 

 are suitable for infants of nine, six and even four months, and has afforded 

 some evidence of their correlation with normal mental development.* 

 Dr. Gesell claims that it can be shown that one month or two of 

 retardation shown at, say, six months of age, suggests a year or two of 

 retardation at six years of age ; and that mental deficiency may be 

 detectable at a very low age by appropriate tests. 



The definite relation of such tests to later estimated intelligence needs 

 to be demonstrated further ; and no doubt, as I shall show later, some of 

 Gesell's individual tests for given ages will need to be modified or aban- 

 doned. For this, the daily study of infants in the home environment 

 is again necessary. Such study suggests that some tests are too dependent 

 on the mood of the moment to be reliable clinical tests. 



In using Gesell's tests I have also found enormous individual variations 

 in the suitability of different tests for a particular child at a given age. 

 Thus, a child of, say, twelve months would be able to do some of Gesell's 

 tests for two-year olds and yet fail in some of those for its own age. 

 Nevertheless, on the whole a fairly steady I.Q. may work out even when 

 only selections of the tests are used, as is shown in the graph below. Here 

 is the performance on Gesell's tests of a child whose I.Q., tested by Binet 

 tests later at ages 2 ; 9, 3 ; 4 and 3 ; 9 worked out on the average at 1.5. 

 Her I.Q. by Gesell tests is as follows : — 



I.Q. by Gesell Tests. 



* See The Mental Groivth of the pre-School Child. 



* The child was troubled with teething at this time, which probably lowered her 

 score. 



^ The tests at 1; 4 were only nine in number, and confined to tests prescribed for 

 1 ; 6. Hence they are ignored in calculating the average I.Q. 



