Cross-cultural study shows how industrialization drove the evolution of maternal care-taking norms

Kushnick G, Hanowell B, Kim J, Lanstieh B, Magnano V, Oláh K (2015) Experimental evidence for convergent evolution of maternal care heuristics in industrialized and small-scale societies. Royal Society Open Science, 2, 140518 (doi: 10.1098/rsos.140518).  PDF  Link

Mother and child in a Karo village, Indonesia

Parental investment theory predicts that mothers will vary their care-giving behavior in ways that maximize fitness. Meaning that maternal decision making should be a tradeoff between the survival of her current offspring and her ability to produce future offspring.

In my new paper, which was written in collaboration with a group of international scholars (the PIVP Project) and published today in the new open-access journal Royal Society Open Science, we found that maternal care heuristics differed markedly between industrialized and small-scale societies. The differences can be thought of as adaptive strategies that arose to deal with the very different care-taking environments found in these societies. This idea is supported by gradients in the order and magnitude of the society-by-society heuristics and various national-level measures, such as total fertility rate, infant mortality rate, expenditures on health, and oil consumption.

The study was conducted in seven societies in six countries. Maternal care heuristics were measured using a vignette experiment whereby women were presented with a description of a hypothetical woman and asked how likely she was to engage in various childcare activities. I had written about the use of these methods to study maternal decision making in previous paper.

Map of fieldsites

The results suggest that the process of industrialization and the shift from kin-based to institutionalized safety nets may have been an important transition in the evolution of human maternal care strategies. Below is a graphical abstract of our findings in the paper.

Graphical abstract of paper.

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The original version of this blog post was posted on my previous, but now-defunct, website on 24 June 2015.