FIGURE 8.12 The Stroop interference task. Test yourself by naming the colors in the top two rows as quickly as you can. Then name the colors of the ink used to print the words in the bottom two rows (do not read the words themselves). Was it harder to name the ink colors in the bottom rows? (Adapted from MacLeod, 2005.)
FIGURE 8.2 Distribution of Stanford-Binet Intelligence Test scores for 3,184 children. (Adapted from Terman & Merrill, 1960.)
FIGURE 8.4 Comparison of an adopted child and a biological child reared in the same family. (Adapted from Kamin, 1981.)
FIGURE 8.3 Approximate correlations between IQ scores for persons with varying degrees of genetic and environmental similarity. Notice that the correlations grow smaller as the degree of genetic similarity declines. Also note that a shared environment increases the correlation in all cases. (Estimates from Bouchard, 1983; Henderson, 1982.)