Premium
IQ,DECLINE IN MENTALLY RETARDED ADULTS: A MATTER OF FACT OR METHODOLOGICAL FLAW
Author(s) -
GOODMAN JOAN F.
Publication year - 1977
Publication title -
journal of intellectual disability research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.941
H-Index - 104
eISSN - 1365-2788
pISSN - 0964-2633
DOI - 10.1111/j.1365-2788.1977.tb00039.x
Subject(s) - attrition , psychology , mentally retarded , intelligence quotient , population , developmental psychology , premise , longitudinal study , psychiatry , demography , cognition , medicine , linguistics , philosophy , dentistry , pathology , sociology
While it has generally been assumed that intelligence in the retarded decreases with age, the institutional research supporting this premise, whether cross-sectional or longitudinal, is methodologically flawed by selective sample attrition. This paper demonstrates that in an institutional population those leaving, at every age level, are indeed the brightest. When the IQ data is viewed cross-sectionally there is the appearance of decline, but when the same population is studied semi-longitudinally, not only is there no decrease in IQ with age but there are regular increments, particularly in performance scores.