38. Benson, J. B., Cherny, S. S., Haith, M. M., & Fulker, D. W. (1993). Rapid assessment of infant predictors of adult IQ: The midtwin/midparent approach. Developmental Psychology, 29, 434-447.

Potential infant predictors of adult IQ were assessed by using a midtwin/midparent design. This design permits the rapid assessment of infant measures to predict later behavior, because the midparent score may be used as a proxy for the infant's potential score at maturity. 114 pairs of same-sex infant twins were observed in their homes at 5, 7 and 9 months on the Fagan Test of Infant Intelligence, hand preference, vocalizations, selected Bayley Scale items and a modified version of the Bayley Infant Behavior Record. At 8 months of age, twins were tested in the laboratory on the Visual Expectation Paradigm and an auditory discrimination task while their parents received a standardized IQ test, the WAIS-R. Results indicated that some infant measures of intellectual processes indicative of speed of processing, attention, recognition memory, language ability and temperamental attributes were predictive of midparent IQ. Because many of these measures were modified from those that were collected from a previous midtwin/midparent cohort (DiLalla, Thompson, Plomin, Phillips, Fagan, Haith, Cyphers, & Fulker, 1990), the present study extends earlier research and replicates some, but not all, of the earlier findings.