Biological Basis of Aggression:
Studies show that mild electrical stimulation of a specific region of the hypothalamus - produces aggressive behaviour in animals. When a cat's hypothalamus was stimulated by implanting electrodes in the brain and passing an electric current, it's hair stood on end; it hissed and arched it's back and would strike at anything that was placed in its cage.
In higher mammals like monkeys this instinctive pattern is not observed. Their behaviour was seen to be more controlled by the cerebral cortex rather than mere stimulation of the hypothalamus. The hypothythus may send a message to the cerebral cortex that its aggressive centres have bcen stimulated, the cortex then chooses the response considering what is going on in the environment, and what has been stored in the memory from past experiences.
We too have centres in thc brain that can make us behave aggressively, but thefactivation is under cognitive control. Some brain damaged persons may react to stimulation with aggressive behaviour, which would not elicit any response from normal persons. In such cases, it was found that the cerebral cortex was the damaged area ot the brain. In normal persons. we can say that aggressive hehaviour is determined largkly by social influences and personal experiences.