RAPID ASSESSMENT OF INFANT PREDICTORS OF ADULT IQ - MIDTWIN MIDPARENT ANALYSES

Infant predictors of adult IQ were assessed with same-sex infant twins (1 14 pairs) and their parents. The midtwin-midparent design permits the rapid assessment of infant measures to predict later behavior, because the midparent score serves as a proxy for the infant's potential score at maturity. At 5, 7, and 9 months, Ss were observed on the Fagan Test of Infant Intelligence, hand preference, vocalizations. selected Bayley Scales of Infant Development items, and a modified Bayley Infant Behavior Record. At 8 months, Ss received the Visual Expectation Paradigm and an auditory discrimination task. Their parents received the Wechsler Adult Intelligence Scale-Revised. Some infant measures, indicative of information processing, language ability, and temperament, predicted midparent IQ. This study extended and partially replicated findings from a previous midtwin-midparent cohort (L. F. DiLalla et al., 1990).