In psychology there is a lot of discussion about the meaning of the term "aggression", since many different people have different opinions on how to define it, one definition comes from Berkowitz 1993 and states that aggression is "behavior intended to hurt someone physically or psychologically." Many explanations for aggression have been proposed and there is a rift between the highly reductionist biological approach and the less reductionist social psychological approaches. Each of these explanations has proven extremely useful in answering some questions about aggression and helping us gain a greater understanding of aggressive behavior, however their limitations must also be recognized. Psychologists with a biological and physiological background tend to view aggression as singularly influenced by underlying internal systems. The genetic explanation, for example, states that genes influence elements of our biology that contribute to aggressive behavior. The theory proposes that it is a combination of structural and functional effects that contribute to an animal's aggressive behavior. (Renfrew 1997) Many twin studies offer support for the genetic approach and although the results of correlational studies have varied, what remains constant across studies is a greater association of aggression with MZ twins compared to Dz twins, both bred together or apart, strongly indicating a genetic contribution. . McGuffin et al found that MZ twins' aggression levels were more correlated at 0.87 than DZ twins at 0.72, O'Connor 1980 found a correlation of 0.72 between MZ twins while Canter found a weak correlation of 0.14 thus suggesting that other factors played a greater role. Correlation results clearly show that genes are an important factor, however...... half of the article ...... conditions were 76% better than the control group. Internet Reference The effectiveness of this treatment therefore provides support for psychological theories of aggression, Jenson suggests, however, that psychosocial therapy in combination with medication may be more effective in treating aggression than medication alone. In conclusion, reductionist approaches can be useful for explaining aggression, however it depends on what questions are asked about a topic, the more significant a question is the less it can be explained with a reductionist approach. On their own, reductionist approaches do not explain all aspects of behavior, and an integrated approach, such as looking at the role of biology on aggression as well as possible social and environmental factors, may be more useful in fully explaining which contributing factors may influence a behavior. person to engage in aggressive behavior.