As humans, we share most of our biological make-up with our closest primate relatives, yet we stand out not just from them but from all other species with respect to our cultural diversity, our capacity for language, and particularly our cognitive skills. While of prime interest for the field of cognitive science, the still-open question of which factors gave rise to human uniqueness has rarely surfaced at its conferences or in its journals. A hallmark of humankind, our propensity for engaging in social interactions and cultural transmission, is likely one of the most essential pre-conditions of cognitive evolution, accompanied by both language (Christiansen & Kirby, 2003) and material culture (Malafouris, 2013). Accounting for evolutionary change in human cognition thus requires new conceptual frameworks that view our psychological, behavioral, and material capabilities as interacting in complex manners in a continuous process of co-evolution (Richerson & Christiansen, 2013).