TY - JOUR
T1 - Path analysis of IQ during infancy and early childhood and an index of the home environment in the Colorado Adoption Project
AU - Rice, Treva
AU - Fulker, D. W.
AU - DeFries, J. C.
AU - Plomin, Robert
N1 - Funding Information:
The first path model of parent-offspring resemblance for cognitive ability was reported by Barbara Burks in 1928. However, in this classic adoption study, only manifest variables of midparental intelligence and a measure of the home en- This work was supported in part by grants from the NSF (BNS-7826204 and BN$-8200310) and from the NICHD (HD-10333 and HD-19426). We are grateful to the families participating in the Colorado Adoption Project, who have so generously contributed their time and effort, and to the adoption agencies who made the study possible--Lutheran Social Services of Colorado and Denver Catholic Community Services. We appreciate the expert editorial assistance of Rebecca G. Miles.
PY - 1988
Y1 - 1988
N2 - A parent-offspring adoption path model, which includes a measured index of the home environment, was formulated to assess the extent to which relationships between the environmental index and children's behavior are mediated by genetic and environmental influences of the parents. In addition to the direct effect of the home environment on children's behavior, three types of indirect effects mediated by parental phenotype are considered: a pure environmental effect, a pure genetic effect, and a combined environmental-genetic effect. To illustrate its application, the model was fitted to parental and offspring IQ data collected in the Colorado Adoption Project and an environmental index based on Caldwell and Bradley's (1978) Home Observation for Measurement of the Environment (HOME). Four sets of data, including the HOME index and offspring IQ measured longitudinally at 1, 2, 3, and 4 years of age, were analyzed. The results suggest that in infancy (ages 1 and 2), the HOME reveals a direct environmental effect on children's IQ as well as indirect effects mediated via parental IQ. Surprisingly, during early childhood (ages 3 and 4), the relationship between the HOME and children's IQ is due only to indirect parental mediation. Moreover, other than at year 1, the mediation is purely genetic.
AB - A parent-offspring adoption path model, which includes a measured index of the home environment, was formulated to assess the extent to which relationships between the environmental index and children's behavior are mediated by genetic and environmental influences of the parents. In addition to the direct effect of the home environment on children's behavior, three types of indirect effects mediated by parental phenotype are considered: a pure environmental effect, a pure genetic effect, and a combined environmental-genetic effect. To illustrate its application, the model was fitted to parental and offspring IQ data collected in the Colorado Adoption Project and an environmental index based on Caldwell and Bradley's (1978) Home Observation for Measurement of the Environment (HOME). Four sets of data, including the HOME index and offspring IQ measured longitudinally at 1, 2, 3, and 4 years of age, were analyzed. The results suggest that in infancy (ages 1 and 2), the HOME reveals a direct environmental effect on children's IQ as well as indirect effects mediated via parental IQ. Surprisingly, during early childhood (ages 3 and 4), the relationship between the HOME and children's IQ is due only to indirect parental mediation. Moreover, other than at year 1, the mediation is purely genetic.
UR - http://www.scopus.com/inward/record.url?scp=38249032410&partnerID=8YFLogxK
U2 - 10.1016/0160-2896(88)90021-9
DO - 10.1016/0160-2896(88)90021-9
M3 - Article
AN - SCOPUS:38249032410
SN - 0160-2896
VL - 12
SP - 27
EP - 45
JO - Intelligence
JF - Intelligence
IS - 1
ER -