External stimulus means you’re with other humans that you can cooperate with. That you’re sharing stories and learning. That you’re hunting for food. That you’re building a shelter. All these things are necessary for survival. It seems possible that being sociable and industrious might well have been bread into us at some point. And it’s probably the reason we aren’t like big cats in Africa, just hunting and then resting to conserve energy.
We should not be suggesting to people that their instincts are a moral failure to be cured.