AP PSYCHOLOGY

Detailed explanation-1: -Even when identical twins are adopted by two different families, their scores are very similar. Scans of identical twins’ brains reveal that gray-and white-matter volume is similar, and areas associated with verbal and spatial intelligence are virtually the same (Deary et al., 2009; Thompson et al., 2001).

Detailed explanation-2: -The correlation of intelligence test scores for identical twins raised together is about +. 85. For identical twins raised apart, the correlation is about +. 72.

Detailed explanation-3: -In this investigation, researchers found that identical twins raised together and identical twins raised apart exhibit a higher correlation between their IQ scores than siblings or fraternal twins raised together (Bouchard, Lykken, McGue, Segal, & Tellegen, 1990).

Detailed explanation-4: -Early twin studies of adult individuals have found a heritability of IQ between 57% and 73%, with some recent studies showing heritability for IQ as high as 80%. IQ goes from being weakly correlated with genetics for children, to being strongly correlated with genetics for late teens and adults.

Detailed explanation-5: -When people have identical genes, the differences in their intelligence are influenced: completely by environment. Research suggests that the one factor that distinguishes gifted children from their moderately intelligent peers is: the amount of time that they devote to their area of excellence.