Behavioral and Brain Sciences

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The evolution of misbelief

Ryan T. McKaya1 and Daniel C. Dennetta2

a1 Institute for Empirical Research in Economics, University of Zurich, Zurich 8006, Switzerland; and Centre for Anthropology and Mind, University of Oxford, Oxford OX2 6PE, United Kingdom

a2 The Center for Cognitive Studies, Tufts University, Medford, MA 02155-7059


From an evolutionary standpoint, a default presumption is that true beliefs are adaptive and misbeliefs maladaptive. But if humans are biologically engineered to appraise the world accurately and to form true beliefs, how are we to explain the routine exceptions to this rule? How can we account for mistaken beliefs, bizarre delusions, and instances of self-deception? We explore this question in some detail. We begin by articulating a distinction between two general types of misbelief: those resulting from a breakdown in the normal functioning of the belief formation system (e.g., delusions) and those arising in the normal course of that system's operations (e.g., beliefs based on incomplete or inaccurate information). The former are instances of biological dysfunction or pathology, reflecting “culpable” limitations of evolutionary design. Although the latter category includes undesirable (but tolerable) by-products of “forgivably” limited design, our quarry is a contentious subclass of this category: misbeliefs best conceived as design features. Such misbeliefs, unlike occasional lucky falsehoods, would have been systematically adaptive in the evolutionary past. Such misbeliefs, furthermore, would not be reducible to judicious – but doxastically1 noncommittal – action policies. Finally, such misbeliefs would have been adaptive in themselves, constituting more than mere by-products of adaptively biased misbelief-producing systems. We explore a range of potential candidates for evolved misbelief, and conclude that, of those surveyed, only positive illusions meet our criteria.

Ryan T. Mc Kay is a Research Fellow at the University of Oxford, UK. He was educated at the University of Western Australia (B.Sc. Hons. in Psychology) and at Macquarie University (MClinPsych, Ph.D.) in Sydney, Australia. His research interests include cognitive neuropsychiatry, evolutionary psychology, and behavioural economics. He has held previous postdoctoral positions in Boston (Tufts University), Belfast (Queen's University), and Zü rich (University of Zü rich). He has also previously worked as a clinical neuropsychologist at the National Hospital for Neurology and Neurosurgery in London and as a lecturer in psychology at Charles Sturt University in Australia. Recently, he has been conducting experimental investigations in the cognitive science of religion.

Daniel C. Dennett is University Professor, Fletcher Professor of Philosophy, and Co-Director of the Center for Cognitive Studies at Tufts University. He is the author of Consciousness Explained (1991), Darwin's Dangerous Idea (1995) and Breaking the Spell: Religion as a Natural Phenomenon (2006), as well as other books and articles in philosophy of mind, cognitive science, and evolutionary theory. He is also the author or coauthor of three target articles (1983, 1988, 1992) and 32 commentaries in Behavioral and Brain Sciences and was an Associate Editor of the journal for many years.