Humor: It's a Guy Thing (You Wouldn't Understand)

This explains why none of my girlfriends ever thought I was funny.

ScienceDaily (Dec. 20, 2007) — Humour appears to develop from aggression caused by male hormones, according to a study published in the Christmas issue of the British Medical Journal.

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Responses became more verbal during the later teens, turning into disparaging 'jokes' or mocking songs. This then evolved into adult male humour -- characterized by repetitive, humorous verbal put-downs concealing a latent aggression. Young men in cars were particularly aggressive. Professor Shuster notes that this is the age when men are at the peak of their virility. The 'jokes' were lost with age as older men responded more neutrally and amicably with few attempts at a jovial put-down.