Abstract: During joint action, adults often co-represent the partner's task and actions. To investigate the evolutionary and ontogenetic origin of co-representation, we used the joint Simon task and compared 4 primate species: marmosets monkeys, who like humans are cooperative breeders and therefore systematically cooperate during their everyday life, capuchin monkeys and Tonkean macaques who are less cooperative, and human children (2-5 years). We found i) corepresentation in all primates, including 2 year old humans, revealing that high levels of inhibitory control or Theory of Mind are not a prerequisite for it; ii) that more cooperative primates (i.e. children and marmosets) were better at preventing that co-representation would negatively affect their cooperation success; and iii) that only marmosets and toddlers relied on mutual gaze to solve the conflict between self-other integration and distinction. I will end by highlighting implications of these results for the evolution of corepresentation and human hypercooperation.

Bio: Judith Burkart is a professor in Evolutionary Anthropology at the University of Zurich. With a background in Developmental Psychology and Neurobiology, she investigates the evolutionary origin of the human mind by studying nonhuman primates. Of particular interest are marmoset monkeys, studied in the wild and in captivity, because like in humans, the entire group helps raising their offspring. They thus help testing the cooperative breeding model of human evolution, which is one of the key goals of her research group.