Humour in most men develops from aggression - an it all starts at puberty, says a new study.
Researchers at Newcastle University have based their findings on an analysis of the reactions of men and women on seeing a trick cyclist, the 'Journal of Psychology Research and Behaviour Management' reported.

The results revealed big differences between male and female response - nine out of 10 women would make warm, kind and encouraging remarks, while young children were interested and curious.

But as boys grew older, their reactions became increasingly unpleasant. Curiosity typically turned into physical and verbal aggression, and they would throw stones or attempt to obstruct the rider by shouting, 'Fall off!' Grown men suppressed the urge to injure the rider, but became snide and aggressive, and would often make jokes about the single wheel.

In fact, the researchers led by Prof Sam Shuster, studied data from more than 30 unicyclists aged between 15 and 69, from the UK and across the world, with up to 40 years' experience.

They discovered an astonishing consistency of responses from boys and men, regardless of social class, geography or era, which suggests a common biological mechanism.

Changes in male hormones, which are associated with aggression, around the time of puberty, account for this.