Determinants of agressivity

Dr Mike Eslea in Lancashire is an expert on aggression. He has shown in the past that direct or indirect exposure to violence on TV can influence how aggressively you'll respond to a stimulus. He's also shown also that children with severe behavioral problems fail to respond to positive or negative reinforcements. And we've all witnessed what kind of adults those make. There is even evidence that psychopathic behavior can be the result of brain lesions. In his latest research he's also shown that short people are not more aggressive than tall people. It seems science has busted this urban myth. In fact when prompted with an aggressive stimulus, the heart rate of tall man climbed faster than that of short man. The "chopstick" game they played consisted of hitting each other's knuckles with sticks! However I suspect that differences could be due to physiology rather than aggressiveness. I wonder also if it would be different if the short man were in presence of tall man at the time.