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Distribution of juvenile delinquent intelligence test scores over a thirty‐four year period (N = 51,808)
Author(s) -
Caplan Nathan S.,
Siebert Lawrence A.
Publication year - 1964
Publication title -
journal of clinical psychology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.124
H-Index - 119
eISSN - 1097-4679
pISSN - 0021-9762
DOI - 10.1002/1097-4679(196404)20:2<242::aid-jclp2270200213>3.0.co;2-j
Subject(s) - intelligence quotient , juvenile , psychology , juvenile delinquency , intellectual ability , test (biology) , borderline intellectual functioning , stanford–binet intelligence scales , intellectual development , demography , juvenile court , developmental psychology , psychiatry , cognition , paleontology , genetics , sociology , biology
Data collected at the Juvenile Court of Cuyahoga County show that a marked increase in the IQ scores of 51,808 juveniles tested during the past 34 years, has occurred. Whereas the mean IQ score from 1929 through 1934 was 80.0, the mean IQ from 1957 through 1962 was 92.1. A detailed analysis of the data revealed that there are apparently at least two reasons for this increase. The most marked increase in IQ scores appears to have been the consequence of changes in the tests employed and, in particular, the replacement of the 1916 Binet by more sensitive tests with higher ceilings. A second source of increase in IQ status appears to have occurred because of non‐test related factors resulting in a slight, but genuine improvement in the intellectual calibre of the children tested. This pattern of fluctuating but gradual improvement is possibly due to social and other conditions increasingly favorable to intellectual growth and development.