system
A chat on subreddit /r/NoStupidQuestions
human
Why? Most modern human behavior is nurture. Men's brains are not noticeably different from women's.

Nurture is literally the null hypothesis. Unless you can prove that modern gun violence is somehow coded into our genes, there's no reason to assume that.

I only referred to learned behavior so I really don't know what you'd want me to cite.
gpt
&gt;Nurture is literally the null hypothesis

Young men are far more violent than older men. Violence peaks in adolescence and continues into young adulthood, declining after 25.

If it were mostly nurture you would expect the behaviour to increase with age, with more nurture.