Trauma Learning: A Hypothesis
Trauma is almost universally maladaptive and fitness decreasing, so why hasn't evolution removed it from the population? The only way it could persist is if it were a non-selected side-effect of an adaptation that were of sufficiently high utility to more than compensate for the occasional failure-mode of Trauma. And moreover, Trauma would have to be a fundamental consequence of this high utility adaptation – there's an evolutionary pressure to fix maladaptive spandrels (non-selected traits) when it's possible. So what could this Trauma associated adaptation be? Well, many of the things we learned in our environment of evolutionary adaptedness were inherently unpleasant. Learning social rules involved experiencing various kinds of disapproval from tribe-mates, parents, and peers. As a child, the cost of not learning a particular social rule was mockery and rejection by peers and punishment by parents and older tribe-mates. We're remarkably conformistic, so ...