Submitted By surfacepro
Words: 1262
Pages: 6

The article I choose to summarize and analyze is Testosterone Rules by Robert M. Sapolsky. Sapolsky examines and deconstructs the notion that testosterone is the direct cause of aggression. He uses logic and facts to tear apart this common misconception and takes it a step further by proposing an alternative hypothesis that downplays the importance of biological influence on behavior. Sapolsky begins by describing a term called physics envy, this is when scientists, specifically behavioral biologists, “fear [that] their discipline lacks […] rigor [and] clarity” (Sapolsky 9). Because of physics envy scientists strive to produce results that are definitive and indisputable, he goes on to explain that correlation does not equal causation. Although testosterone plays a role in the presence of aggression, it does not produce aggression. He then uses logic to deconstruct what scientists have deemed “normal levels of testosterone” (Sapolsky 9). If there is indeed a fixed level of testosterone that produced what is considered normal levels of aggression, he points out that an individual that naturally produces more testosterone is not necessarily more aggressive (Sapolsky 9). He paraphrases several studies that further dispute what scientists have so long believed. He explains that when an individual is castrated their testosterone level drops to zero but their levels of aggression do not, which indicates that testosterone is not solely responsible for aggression. Furthermore, if an individual is injected with testosterone anywhere between “20 per cent of [pre-castration levels]” (Sapolsky 9) to twice the amount of their pre-castration levels, aggression falls within the normal pre-castration levels as well, thus indicating that the brain cannot tell the difference (Sapolsky 9). Sapolsky provides more evidence by looking very closely at the impact testosterone has on the brain, specifically between the hypothalamus and the amygdala. The amygdala send electrical impulses to the hypothalamus with the help of testosterone and thus triggers the expression of aggression (Sapolsky 10). Testosterone simply increases the speed at which these signals travels at, but it cannot activate the pathway on its own, therefore it exaggerates pre-existing aggression (Sapolsky 10). He continues this deconstruction by bringing up the importance of the environment and social factors with two prime examples, rhesus monkeys and spotted hyenas. Rhesus monkeys and hyenas both live within social hierarchies in which there are dominant and subordinate individuals. In the case of the Rhesus monkey, a group is placed in an enclosed environment and has established a hierarchy, if one of the subordinate monkeys is injected with large levels of testosterone he displays aggression towards other more subordinate monkeys but does not display aggression towards the dominant monkeys (Sapolsky, 10). This indicates that although aggression has increased in the one monkey its expression is heavily influenced by the social hierarchy that is already in place. In the case of the spotted hyena, females are born with higher levels of testosterone and are subsequently more dominant and aggressive than males (Sapolsky 10). When raised in captivity, the typical social order where females are more dominant and aggressive towards males is delayed considerably because they are unable to learn social order from other hyenas as they would in the wild (Sapolsky 10). Even though female hyenas have more testosterone their aggression is stifled until a social hierarchy is established. This is an indication that although testosterone is associated with aggression the environment has a substantial impact on its expression. Sapolsky concludes that aggression is a complex behavior that is predominantly caused by “social factors and [the] environment in which it occurs” (Sapolsky 11).
I am particularly drawn to this article due to my interest in the sciences and biology. Before entering this