Spousal Age Differences and Sex Differences in Life Expectancy are Confounders of Matrilateral Biases in Kin Investment

Abstract

Several evolution-based theories predict discriminative kin investment in humans. Previous research indicates that a matrilateral bias exists, such that maternal relatives invest the most in grandchildren due to the high degree of certainty of biological relatedness. In a sample of 321 Austrian adults, we failed to replicate previous findings using retrospective solicitude ratings and ratings of emotional closeness for grandparent–grandchild and aunt/uncle–niece/nephew relationships. However, exposure time to (i.e., number of years where relative was alive), and residential distance from, the relatives were found to be confounding variables on these commonly used measures of investment.

Notes

Note. Table entries represent means (standard deviations in parentheses).

Note. df = denominator degrees of freedom for the F tests (numerator dfs are one in each case).

Note. df = denominator degrees of freedom for the F tests (numerator dfs are one in each case).