 Appreciation of the blind spots and questionable inferences highlighted by the WEIRD challenge has contributed to substantive theorizing about minds as well. It has informed work focused on establishing the existence and character of psychological variation, but also made urgent the need to develop a more sophisticated range of theoretical resources to explain that variation. Questions here have often been framed using contemporary versions of the distinction between innate and acquired traits (Carruthers et al. 2005, 2006, 2007). While theses about the presence and significance of innate mental characteristics have loomed large in the history of Western thought (Samet 2008 [2019]; Markie &amp; Folescu 2021), the distinction and its attendant concepts are not philosophically unproblematic (Griffiths 2002; Mallon &amp; Weinberg 2006; Griffiths &amp; Machery 2008; Gross &amp; Rey 2012). Nevertheless, much research has sought to illuminate which aspects of mental structure and content (and even personality, see Gurven et al. 2013; Smaldino, Lukaszewski, et al. 2019) might be part of a genetically shared, (quasi-)universal human psychological nature, and which aspects can vary between groups, and how much (Roughley 2021). Further efforts have been directed at discovering, of those aspects that are acquired and that do exhibit variation, which are obtained via individual learning, and which are culturally ‘inherited’, acquired via (a particular type of) social learning. This framing has in turn brought increased scrutiny to the psychology of learning itself, and especially the structure and provenance of those cognitive mechanisms that underlie different forms of social transmission. Research on this front will be the focus of  Section 3.2  and  Section 3.3.