ERIC Number: ED251245
Record Type: RIE
Publication Date: 1984-Aug
Reference Count: 0
Environmental Sources of Intelligence Differences among Separated Identical Twins.
Franke, Richard H.; Paduch, Pamela J.
Since the time of Galton, high correlations have been noted in the IQ levels of identical twins, with relationships for twins reared in different families being only slightly lower than for twins reared together. This evidence has been held to demonstrate that intellectual differences among individuals and among groups are largely determined by genetics, and to suggest the futility of educational programs to remedy environmental deficiences. In the present study, an alternate procedure is used that avoids the participation of common environmental factors in the apparent genetic correlation of IQ levels. This procedure involves relating differences in IQ between separated identical twins to differences in the environments experienced. By stepwise multiple regression, 78 percent of the variance in inter-twin IQ difference is explained by differences in educational, physical, and family environment. Reanalysis of a "classical" set of data from separated identical twins indicates specific environmental factors that can be substantial determinants of intellectual development, even given the relatively benign conditions generally experienced in the United States. (Author/RH)
Publication Type: Reports - Research; Speeches/Meeting Papers
Education Level: N/A
Authoring Institution: N/A
Note: Paper presented at the Annual Convention of the American Psychological Association (92nd, Toronto, Ontario, Canada, August 24-28, 1984).