Presents a study of the cumulative deficit hypothesis and a discussion of some of the theoretical issues and methodological problems involved. Results of the study indicate a significant age decrement in verbal, but not nonverbal, IQ among a large sample of Negro elementary school children. (Author/ED)

Study results indicate that correlations between measures of the home environment and children's intelligence quotient at 7 years of age are often mediated genetically. Among 153 adoptive and 136 nonadoptive families, such correlations were generally lower in adoptive families than in nonadoptive families. (RH)