title: Experimental evidence for convergent evolution of maternal care heuristics in industrialized and small-scale populations.
abstract: Maternal care decision rules should evolve responsiveness to factors impinging on the fitness pay-offs of care. Because the caretaking environments common in industrialized and small-scale societies vary in predictable ways, we hypothesize that heuristics guiding maternal behaviour will also differ between these two types of populations. We used a factorial vignette experiment to elicit third-party judgements about likely caretaking decisions of a hypothetical mother and her child when various fitness-relevant factors (maternal age and access to resources, and offspring age, sex and quality) were varied systematically in seven populations-three industrialized and four small-scale. Despite considerable variation in responses, we found that three of five main effects, and the two severity effects, exhibited statistically significant industrialized/ small-scale population differences. All differences could be explained as adaptive solutions to industrialized versus small-scale caretaking environments. Further, we found gradients in the relationship between the population-specific estimates and national-level socio-economic indicators, further implicating important aspects of the variation in industrialized and small-scale caretaking environments in shaping heuristics. Although there is mounting evidence for a genetic component to human maternal behaviour, there is no current evidence for interpopulation variation in candidate genes. We nonetheless suggest that heuristics guiding maternal behaviour in diverse societies emerge via convergent evolution in response to similar selective pressures.
authors.affiliation: School of Archaeology and Anthropology, The Australian National University , Canberra, Australia.
authors.forename: Geoff
authors.initials: G
authors.lastname: Kushnick
authors.affiliation: Analytics Department, Redfin Corporation , Seattle, WA, USA.
authors.forename: Ben
authors.initials: B
authors.lastname: Hanowell
authors.affiliation: Institute of Cross-Cultural Studies, Seoul National University , Seoul, South Korea.
authors.forename: Jun-Hong
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Department of Anthropology , North-Eastern Hill University , Shillong, India.
authors.forename: Banrida
authors.initials: B
authors.lastname: Langstieh
authors.affiliation: Department of Dentistry , Universidad Europea de Valencia , Valencia, Spain.
authors.forename: Vittorio
authors.initials: V
authors.lastname: Magnano
authors.affiliation: Department of Cognitive Psychology , Eötvös Loránd University , Budapest, Hungary ; Institute of Cognitive Neuroscience, Hungarian Academy of Sciences , Budapest, Hungary.
authors.forename: Katalin
authors.initials: K
authors.lastname: Oláh
keywords: behavioural ecology; convergent evolution; maternal care; vignette experiment