There are differences between aggression in men and women, which may have a biological basis, but they are also tempered by psychological parameters and socialization issues (Archer, 1991; Fishbein, 1992). In animals, aggression is usually studied in terms of behavior alone, but in humans aggression encompasses the intention to harm another person, some form of behavior carried out as a result of this intention, and an emotion which can be anything from mere irritation to outright rage (Archer, 1991). While there are no outright statistics, males usually tend to be more aggressive than females in terms of physical and verbal aggression. A still unanswered question is how much of this difference is biological and how much is psychological. Differences are not only found between genders, but also with age and education (aggression decreasing with increasing age and education level), and between different ethnic groups (Harris and Knight-Bohnhoff, 1996).
The influence of genes on personality has been studied by comparing identical twins raised in separate environments and the studies have shown that genes have a decided influence over personality (Colt and Kuehn, 1998). Physiological and psychological testing of pairs of both identical and fraternal twins has usually shown that character traits are approximately 60 percent due to inheritance. For instance, assertiveness is 60 percent inherited, while body mass appears to be 70 percent inherited. Researchers in the Netherlands reported on a large Dutch family who have a genetic mutation which may cause periodic outbursts of aggression (Evidence, 1993). The mutation is in the gene for monoamine oxidase A (MAOA). This enzyme aids in the breakdown of the neurotransmitters dopamine, epinephrine, norepinephrine and serotonin. Other studies of individuals showing aggressive behavior have also shown the same neurochemical findings according to the National Institute for Alcohol Abu...