PARENT‐OFFSPRING RESEMBLANCES IN INTELLIGENCE: THEORIES AND EVIDENCE

Abstract

Data on parent-offspring resemblances in intelligence is reviewed in the context of correlation, regression and variance predictions from the polygenic model and an environmental model. Reliability, test equivalence and long-term stability of IQ scores were considered. Much of the difference among offspring IQ scores is not directly attributable to parental IQ, and some is due to other between-family variables. The magnitude of single-parent-offspring correlations was related to the degree of assortative mating present in samples. Evidence on whether parent-offspring resemblances in IQ are transmitted genetically or environmentally is lacking. A single study provides evidence for some degree of genetic transmission, but the present polygenic model is inadequate.