Aggression and Body Chemistry

In most species, including humans, males are more aggressive than females.
This is thought to be because of the testosterone levels present in varying degrees
in males. The higher the testosterone level, the more aggressive the
male. Aggressive behavior that threatens the welfare of the species is often
controlled in humans by medication that reduces the testosterone levels
and pacifies aggressive men.
It is notable that young men tend to be considerably more aggressive
than older males, presumably because as men age, their testosterone levels
decrease considerably. Prisons are filled with young men unable to control
their aggressions sufficiently to stay out of trouble with the law. Many of
these prisoners mellow into relatively benign older men, not because prison
has reformed them but because their body chemistry has undergone significant
changes through the years.
At one time, aggressive behavior was controlled by electric shock therapy
(which is used at present in some extreme cases) or by the more drastic surgical
procedure known as lobotomy. Lobotomies often left people in virtually
catatonic states from which they could never emerge. Drugs and psychiatric
treatment have replaced most of the more devastating procedures of
the nineteenth and twentieth centuries.