The what and why of self-deception

•We compare three types of definitions of self-deception.•We present three hypotheses regarding the adaptive nature of self-deception.•We review recent empirical research providing evidence for all three.

Scholars from many disciplines have investigated self-deception, but defining self-deception and establishing its possible benefits have been a matter of heated debate — a debate impoverished by a relative lack of empirical research. Drawing on recent research, we first classify three distinct definitions of self-deception, ranging from a view that self-deception is synonymous with positive illusions to a more stringent view that self-deception requires the presence of simultaneous conflicting beliefs. We then review recent research on the possible benefits of self-deception, identifying three adaptive functions: deceiving others, social status, and psychological benefits. We suggest potential directions for future research.