One category of cases where self-deception might be (evolutionarily) adaptive would be for males to be over-confident about their chances to pick up a female for a one-night stand (or, alternative, over-confident about how pleasurable that dalliance would be, and/or about how little they would be emotionally hurt by a rejection of their advances).
Suppose that in reality the potential utility to the male of the 1-night stand (if the seduction works) is twice as much as the utility loss (if rejected) and the actual chances of success are 20%; in this case the male will never make such pick-up attempts if they have exactly correct estimations. Another male who self-deceives to believe their chances are 40% will try every time—and some of the time they’ll get the 1-nighter, and some of that time they’ll sire a baby and spread their genes. Thus, in such a situation, self-deceiving for over-confidence may be adaptive.
One category of cases where self-deception might be (evolutionarily) adaptive would be for males to be over-confident about their chances to pick up a female for a one-night stand (or, alternative, over-confident about how pleasurable that dalliance would be, and/or about how little they would be emotionally hurt by a rejection of their advances).
Suppose that in reality the potential utility to the male of the 1-night stand (if the seduction works) is twice as much as the utility loss (if rejected) and the actual chances of success are 20%; in this case the male will never make such pick-up attempts if they have exactly correct estimations. Another male who self-deceives to believe their chances are 40% will try every time—and some of the time they’ll get the 1-nighter, and some of that time they’ll sire a baby and spread their genes. Thus, in such a situation, self-deceiving for over-confidence may be adaptive.