title: Wealth, fertility and adaptive behaviour in industrial populations.
abstract: The lack of association between wealth and fertility in contemporary industrialized populations has often been used to question the value of an evolutionary perspective on human behaviour. Here, we first present the history of this debate, and the evolutionary explanations for why wealth and fertility (the number of children) are decoupled in modern industrial settings. We suggest that the nature of the relationship between wealth and fertility remains an open question because of the multi-faceted nature of wealth, and because existing cross-sectional studies are ambiguous with respect to how material wealth and fertility are linked. A literature review of longitudinal studies on wealth and fertility shows that the majority of these report positive effects of wealth, although levels of fertility seem to fall below those that would maximize fitness. We emphasize that reproductive decision-making reflects a complex interplay between individual and societal factors that resists simple evolutionary interpretation, and highlight the role of economic insecurity in fertility decisions. We conclude by discussing whether the wealth-fertility relationship can inform us about the adaptiveness of modern fertility behaviour, and argue against simplistic claims regarding maladaptive behaviour in humans.
authors.affiliation: Department of Population Health, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK gert.stulp@lshtm.ac.uk.
authors.forename: Gert
authors.identifier: http://orcid.org/0000-0003-0173-5554
authors.initials: G
authors.lastname: Stulp
authors.affiliation: Department of Psychology, University of Lethbridge, Lethbridge, Alberta, Canada T1 K 3M4.
authors.forename: Louise
authors.identifier: http://orcid.org/0000-0003-1841-2997
authors.initials: L
authors.lastname: Barrett
mesh_terms: D000223:Adaptation, Psychological; D019049:Developed Countries; D004467:Economics; D005191:Family Characteristics; D005298:Fertility; D006801:Humans; D043762:Reproductive Behavior / Q000523:psychology
keywords: fitness; human behavioural ecology; income; industrial society; mismatch