Why do people cry out when we're physically injured? I know we retract or nurse whatever has been injured instantaneously, but that's just because of the nervous system's self preservation circuitry, but why does it also trigger a vocal reaction? what possible methods of self preservation could such audible recognition of injury bring? True, it could be taken as a call for help and it's possible others might come in aide, but chances are equally as well that it would show your vulnerability and bolster the attacker encouraging an easy fatality.