4. Thompson, L. A., Fulker, D. W., DeFries, J. C., & Plomin, R. (1986). Multivariate genetic analysis of "environmental" influences on infant cognitive development. British Journal of Developmental Psychology, 4, 347-353.

A multivariate path model of the relationship between environmental measures and measures of infant cognitive development was tested. A maximum-likelihood estimation procedure produced a highly satisfactory fit of the model to the data. The results obtained from fitting a series of simplified models indicate that environmental variables have significant influences on Bayley MDI scores, language development, and a factor from the Bayley IBR termed task orientation. However, these relationships are mediated to a similar extent by hereditary influences.