Using a paired-associate learning task to assess parent-child phenotypic similarity.

The fact of uncertain paternity has led some researchers to hypothesize that children should more closely resemble their fathers than their mothers. The evidence in support of this hypothesis is mixed, partly because the procedures used to measure perceived phenotypic similarity may not be sensitive enough to detect small effects and partly because comparisons are made between fathers and mothers rather than random control groups. In the present experiment the viability of using a paired-associate learning paradigm to investigate parent-child phenotypic similarity is demonstrated using 15 stimulus sets of colored photographs picturing two adults and one child. Using a 2 x 2 between subjects analysis of variance for total errors across learning trials, evidence indicated genetic relatedness for both mothers and fathers influences perceived resemblance and that association of male facial features with those of children, whether paternal or not, are learned more quickly than female facial features. While the significance of genetic relatedness to facial similarity was expected, the overall sex difference was not. However, the additive combination of these variables, genetic relatedness and maleness may explain why children seem to more closely resemble their fathers.