title: Theory of mind: did evolution fool us?
abstract: Theory of Mind (ToM) is the ability to attribute mental states (e.g., beliefs and desires) to other people in order to understand and predict their behaviour. If others are rewarded to compete or cooperate with you, then what they will do depends upon what they believe about you. This is the reason why social interaction induces recursive ToM, of the sort "I think that you think that I think, etc.". Critically, recursion is the common notion behind the definition of sophistication of human language, strategic thinking in games, and, arguably, ToM. Although sophisticated ToM is believed to have high adaptive fitness, broad experimental evidence from behavioural economics, experimental psychology and linguistics point towards limited recursivity in representing other's beliefs. In this work, we test whether such apparent limitation may not in fact be proven to be adaptive, i.e. optimal in an evolutionary sense. First, we propose a meta-Bayesian approach that can predict the behaviour of ToM sophistication phenotypes who engage in social interactions. Second, we measure their adaptive fitness using evolutionary game theory. Our main contribution is to show that one does not have to appeal to biological costs to explain our limited ToM sophistication. In fact, the evolutionary cost/benefit ratio of ToM sophistication is non trivial. This is partly because an informational cost prevents highly sophisticated ToM phenotypes to fully exploit less sophisticated ones (in a competitive context). In addition, cooperation surprisingly favours lower levels of ToM sophistication. Taken together, these quantitative corollaries of the "social Bayesian brain" hypothesis provide an evolutionary account for both the limitation of ToM sophistication in humans as well as the persistence of low ToM sophistication levels.
authors: Motivation, Brain, and Behavior Laboratory, Brain and Spine Institute, Hôpital de la Pitié Salpêtrière Paris, France ; CNRS UMR 7225, INSERM U 975, UPMC Paris, France.
authors: Marie
authors: M
authors: Devaine
authors: Maison des Sciences Economiques, Paris, France.
authors: Guillaume
authors: G
authors: Hollard
authors: Motivation, Brain, and Behavior Laboratory, Brain and Spine Institute, Hôpital de la Pitié Salpêtrière Paris, France ; CNRS UMR 7225, INSERM U 975, UPMC Paris, France ; Wellcome Trust Centre for Neuroimaging, University College London, London, United Kingdom.
authors: Jean
authors: J
authors: Daunizeau
mesh_terms: D005075:Biological Evolution; D005260:Female; D006801:Humans; D008037:Linguistics; D008297:Male; D008954:Models, Biological; D012919:Social Behavior