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 even small and harmless deviations from normative behavior are often met with disapproving glares, the decreased willingness of others to be associated with us, and outright social rejection.

 And, as a result, we're highly sensitive to social disapproval from a very early age – if we weren't, we'd fail to conform as expected to age-appropriate behavioral norms and thus be unable to acquire status in adulthood, which would prevent us from gaining the immense fitness utility that comes with it.

 This would select against anything that leads to open non-conformism, while selecting for a neurotic and hypervigilant fixation on what others would think of our every action, belief, and motive. 

So from birth, we're immersed in a world in which we're beset on all sides by eyes that will glare at us in painful disapproval the moment we violate one of the countless unwritten norms that micromanage nearly every aspect of human life.

 And as a result, from the moment we become cognizant of the fact that other people exist, we face countless and frequent instances of pain as we're trained by signals of disapproval – both verbal and non-verbal – to gradually reject everything free, spontaneous, and playful in ourselves in order to adopt the role we're expected to play, down to the most subtle and micromanaged detail. 

This is a highly unpleasant process, and I think never having known anything else keeps most of us from fully appreciating just how much we were and are tormented by the process of enculturation. 

And the lessons of nature were no more pleasant. Outside of the skinner-box of judgmental eyes that was our sole source of safety, the world was filled with dangers, like predatory monsters, that would eat us alive at the first opportunity. 

So we can safely say that both enculturation and learning how to survive in a brutal eat or be eaten world involved experiencing a wide variety of low valence states.

And I think that this provides a clue to our earlier question of the nature of the adaptation that gave rise to trauma as a non-selected side-effect: most instances of learning to survive in a culture and in the brutality of Darwinian nature are preceded by a sudden low valence shock: Encountering a predator, being rejected, being punished, being the object of a painful signal of disapproval, and so on. 

Low valence qualia were recruited because they are inherently attention grabbing and aversive. And the only reason to recruit a type of qualia that immediately grabs attention away from every other kind of qualia is if the task that they were recruited to perform were deeply important (by evolutionary standards). 

So the very fact that some things are painful attests to the evolutionary importance of learning to avoid them. And thus, the degree of pain we experience in a certain state is a direct indication of the degree of historical evolutionary importance of avoiding it. 

In other words, there's a direct relationship between the degree of painful aversiveness of a particular quale and its degree of importance as a signal of the magnitude of fitness loss or failed fitness gain that a particular situation presents us with. 

We know that major traumas can lead to major dissociation – often to such a degree that a largely autonomous and highly developed dissociated alter can form that encompasses most of the systems in the mind. This is known as dissociative identity disorder, and some forms of it give rise to astonishingly bizarre consequences. 

But do smaller, shorter, and more particular low-valence shocks also lead to their own, more limited, forms of dissociation? This would certainly go a long way toward explaining what adaptive function dissociation has that keeps the phenomenon around.

If small low valence shocks create dissociated models that do nothing but perpetually look out for a particular cause of past pain and generate unpleasant error signals when there are indications that something historically unpleasant might repeat, it could be highly adaptive.

One big faux pas in a superstitious tribal society could lead to death, ostracism or massive status loss, so it would make sense that evolution would create dissociated specialist modules in response to past trauma  - both personally experienced and vicariously acquired by empathically modeling the misfortunes of others -  in order to allow the mind to always be on the lookout for inclusive fitness threatening dangers, without sacrificing the responsiveness of the primary stream of attention to new and unexpected threats and demands.