What role does non-genetic inheritance play in evolution? In recent work we have independently and collectively argued that the existence and scope of non-genetic inheritance systems, including epigenetic inheritance, niche construction/ecological inheritance, and cultural inheritance—alongside certain other theory revisions—necessitates an extension to the neo-Darwinian Modern Synthesis (MS) in the form of an Extended Evolutionary Synthesis (EES). However, this argument has been challenged on the grounds that non-genetic inheritance systems are exclusively proximate mechanisms that serve the ultimate function of calibrating organisms (...) to stochastic environments. In this paper we defend our claims, pointing out that critics of the EES (1) conflate non-genetic inheritance with early 20th-century notions of soft inheritance; (2) misunderstand the nature of the EES in relation to the MS; (3) confuse individual phenotypic plasticity with trans-generational non-genetic inheritance; (4) fail to address the extensive theoretical and empirical literature which shows that non-genetic inheritance can generate novel targets for selection, create new genetic equilibria that would not exist in the absence of non-genetic inheritance, and generate phenotypic variation that is independent of genetic variation; (5) artificially limit ultimate explanations for traits to gene-based selection, which is unsatisfactory for phenotypic traits that originate and spread via non-genetic inheritance systems; and (6) fail to provide an explanation for biological organization. We conclude by noting ways in which we feel that an overly gene-centric theory of evolution is hindering progress in biology and other sciences. (shrink)

A skew in sex ratio at birth occurs across much of Asia and North Africa. The resulting gender imbalance in favor of men in the adult population causes a number of serious social problems, including increased violence against women and an increasing number of “forced bachelors” in many areas. Here we concentrate on the sex ratio at birth in China and model two causal factors specific to Chinese culture: a traditional preference for sons over daughters and a preference for brides (...) to move to their husband’s natal home (virilocal marriage). We use cultural niche construction models to explore the interacting effect of both son preference and marriage-type preference on the demography of the region. Finally, we discuss the implications of this model for policy interventions in the future. (shrink)

As emphasized in early cultural evolutionary theory, understanding heritability of human traits – especially, behavioural traits – is difficult. The target article describes important ways that culture can enhance, or obscure, signatures of heritability in genetic studies. Here, we discuss the utility of calculating heritability for behavioural traits influenced by cultural evolution and point to conceptual and technical complications to consider in future models.

Baumard's perspective asserts that “opportunity is the mother of innovation,” in contrast to the adage ascribing this role to necessity. Drawing on behavioral ecology and cognition, we propose that both extremes – affluence and scarcity – can drive innovation. We suggest that the types of innovations at these two extremes differ and that both rely on mechanisms operating on different time scales.