The semi-longitudinal method was used to trace changes in the mental ages of 906 institutionalized mentally retarded subjects as a function of chronological age, and equations were fitted to the resulting growth curves. Sex differences proved to be relatively slight. The higher levels of retardation had a higher initial growth rate and a more pronounced decline at higher age levels than did the lower levels, but they did not have a longer growing season. In all but the last respect, the findings resembled those obtained by Fisher and Zeaman (1970).
References
1.
ClarkeA. M.ClarkeA. D. B.Mental deficiency: The changing outlook. (3rd ed.) New York: Free Press, 1974.
2.
DemaineG. C.SilversteinA. B.MA changes in institutionalized Down's syndrome persons: A semi-longitudinal approach. American Journal of Mental Deficiency, 1978, 82, 429–432.
3.
FisherM. A.Program to determine growth and decline functions from semi-longitudinal data. Behavior Research Methods and Instrumentation, 1975, 7, 312.
4.
FisherM. A.ZeamanD.Growth and decline of retardate intelligence. International Review of Research in Mental Retardation, 1970, 4, 151–191.
5.
SilversteinA. B.Changes in the measured intelligence of institutionalized retardates as a function of hospital age. Developmental Psychology, 1969, 1, 125–127.
6.
TermanL. M.MerrillM. A.Measuring intelligence: A guide to the administration of the new revised Stanford-Binet tests of intelligence. Boston: Houghton Mifflin, 1937.
7.
TermanL. M.MerrillM. A.Stanford-Binet Intelligence Scale: Manual for the third revision Form L-M. Boston: Houghton Mifflin, 1960.
8.
ZeamanD.HouseB. J.Mongoloid MA is proportional to log CA. Child Development, 1962, 33, 481–488.
