76 PSYCHOLOGICAL METHODS OP TESTING INTELLIGENCE 



But this discussion has already led us from the 

 consideration of mental arrest to the question of 

 the mental retardation of the feeble-minded. Binet 

 used as the measure of retardation simply the dif- 

 ference between mental age and chronological age 

 and was so convinced of the general application of 

 this measure that he looked upon the value "2 

 years " as a general expression for a definite and in 

 fact serious deficiency. 



Binet 's successors also made use of this standard, 

 but their own results teach us that we can not be 

 satisfied with it. For it has become evident that one 

 and the same absolute difference, e. g., a mental re- 

 tardation of three years, means very different things 

 at different years. Thus Kramer (54) remarks : "It 

 should not be concluded that a 12-year old child with 

 a mental age of 9 is of the same degree of feeble- 

 mindedness as an 8-year 21 child with a mental age 

 of 5. In the case of the children turned over to 

 us for examination by the Central Child Welfare 

 Bureau (Jugendfursorgezentrale) it came out clearly 

 that the differences revealed among the younger 

 children were for the most part but small, but 

 among the older children always greater, although 

 the actual defects in these two groups, so far as 

 we could judge them by other criteria, by no means 

 revealed any corresponding difference, but seemed, 

 on the average, to be about the same." Chot- 

 zen (44, p. 493) also corroborates this view: "On 

 account of a checking of development, the mental age 



^Page 29. In the text there is. a typographical error here, 7 in- 

 stead of 8-year. 



