I really don't think there's any great secret to this. The RAF classifies this as a "lack of awareness" or "lack of capacity".
Thankfully, most who suffered from it in training were removed from the course at some stage or other. I think it just comes from a lack of sufficient brain processing power to cope with more than just flying the aircraft. A lack of the ability to multi-task sufficiently, if you like.
Perhaps tens of thousands of years ago, some of their ancestors would have been caught and eaten by what other men were catching and eating.