Human Learning and Paternal Investment

Parental investment strategies are shaped by trade-offs arising from resource allocation decisions. Human males have evolved the broadest range of paternal investment patterns among primates, being the only great ape species that contributes significantly to offspring care. Two biological parents, single mothers, and stepfather containing families are the most common family structures among humans. Offspring learning performance is sensitive to both material and non-material parental investment. We investigated the association between parental investment and adolescent academic performance in an Estonian city about 7 years after post-Soviet transition from state-regulated to market economy.

Data was collected in 1997-1999 from 823 adolescents and their parents, who all gave their consent to the voluntary examination, and analysed anonymously under the license of the Research Ethics Committee of the University of Tartu. We assessed four indicators – paternal tertiary education (reflecting paternal social status and learning capacity), family structure (indicator of the amount of paternal care), self-reported meat shortage (indicator of the availability of nutrient-dense food), and child cranial volume (indication of physiological/genetic condition, but also nutritional environment during development). Age- and sex-specific residuals of cranial volume were calculated based on head length and width. Learning performance was assessed by student self-reports of their academic grades. The effects of predictors on learning performance were studied with ANCOVA analysis.

Family structure predicted offspring learning performance over and above offspring cranial volume, perceived food sufficiency, and paternal education level. Children raised by two biological parents achieved better school grades, and this effect was independent of both child cranial volume and SES-related factors (paternal tertiary education, self-reported meat shortage). Learning performance was positively associated with paternal tertiary education, was better in girls, increased slightly with cranial volume and decreased with growing age. The independent effect sizes for family structure and cranial volume were small.

Funding for this research was provided by the Estonian Research Council grant PRG1137 to Peeter Hõrak.