ENGINE · Engineering Interdependence - A Window into the Evolution of the Human Mind

The human mind is very similar to that of other great apes, yet also strikingly different, and a vast body of research converges on one conclusion: this gap is fundamentally social. Moreover, it emerges early in ontogeny, reflects the distinctly human neurochemical profile, and is characterized by physiological, hormonal, and behavioural synchronicity. But why did this gap evolve in the first place, and why was it us, rather than any of the other great apes, who diverged so dramatically and evolved this unique socio-cognitive niche? Multiple proposals stress interdependence as the key factor during human cognitive evolution, but testing this idea empirically remains a major challenge for the field. ENGINE sets out to do so, by proposing a process-oriented working model of human cognitive evolution in which interdependence takes centre stage, and testing it by engineering interdependence in the marmoset monkey, the emerging next-generation model for human social behaviour. I will thus produce an inter-dependent lineage of marmosets that will only be able to overcome daily challenges (i.e. finding food, defence against out-groups and predators, securing comfort) via mandatory cooperation, whereas an in-dependent lineage will have to overcome these challenges via individual effort. I will investigate downstream effects of this experimentally induced variation in interdependence on neurochemistry, synchronization at various levels, and cognitive outcomes. I will examine both immediate and long-term effects, when mandatory interdependence is experienced during ontogeny and over generations of animals. I will complement this engineering part by studies with human children, and validate it with wild marmosets. ENGINE thus allows us for the first time to comprehensively assess how interdependence affects socio-cognitive functioning in nonhuman primates, which brings us a crucial step forward in understanding how and why the human mind evolved.