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This study examined the effects of prenatal cocaine exposure, environmental risk, and maternal verbal intelligence on children's cognitive ability. Gender and age were examined as moderators of potential cocaine exposure effects. The Stanford-Binet IV intelligence test was administered to 231 children (91 cocaine exposed, 140 unexposed) at ages 4, 6, and 9 years. Neonatal medical risk and other prenatal exposures (alcohol, cigarettes, and marijuana) were also examined for their unique effects on child IQ. Mixed models analysis indicated that prenatal cocaine exposure interacted with gender, as cocaine-exposed boys had lower composite IQ scores. Age at assessment did not moderate this relation, indicating that cocaine-exposed boys had lower IQs across this age period. A stimulating home environment and high maternal verbal IQ also predicted higher composite IQ scores. Cocaine-exposed boys had lower scores on the Abstract/Visual Reasoning subscale, with trends for lower scores on the Short-Term Memory and Verbal Reasoning subscales, as exposure effects were observed across domains. The findings indicate that cocaine exposure continues to place children at risk for mild cognitive deficits into preadolescence. Possible mechanisms for the Exposure x Gender interaction are discussed. (Contains 1 footnote, 3 tables, and 1 figure.)

Differentiation models contend that the organization of facial expressivity increases during infancy. Accordingly, infants are believed to exhibit increasingly specific facial expressions in response to stimuli as a function of development. This study tested this hypothesis in a sample of 151 infants (83 boys and 68 girls) observed in 4 situations (tickle, sour taste, arm restraint, and masked stranger) at 4 and 12 months of age. Three of the 4 situations showed evidence of increasing specificity over time. In response to tickle, the number of infants exhibiting joy expressions increased and the number exhibiting interest, surprise, and surprise blends decreased from 4 to 12 months. In tasting a sour substance, more infants exhibited disgust and fewer exhibited joy and interest expressions, and fear and surprise blends over time. For arm restraint, more infants exhibited anger expressions and anger blends and fewer exhibited interest and surprise expressions and surprise blends over time. In response to a masked stranger, however, no evidence of increased specificity was found. Overall, these findings suggest that infants increasingly exhibit particular expressions in response to specific stimuli during the 1st year of life. These data provide partial support for the hypothesis that facial expressivity becomes increasingly organized over time. (Contains 2 footnotes, 1 table, and 1 figure.)