Aggression vs Altruism

Aggressive behavior is related to the monoamine neurotransmitters serotonin, dopamine, and noradrenaline. The enzymes monoamine oxidase (MAO) A and B play roles in the metabolism of catecholamines in the brain and peripheral tissues. MAOA degrades dopamine, serotonin, and noradrenaline. 

Brunner et al. (1993) found that aggressive behavior was associated with a mutation of the gene for the enzyme MAOA (Science 262 578-580,1993). In men with borderline mental retardation and aggressive tendencies, they found greatiy reduced MAO activity. Mutations of the C936T gene were related to criminal/antisocial behavior. 

Childhood maltreatment can lead to antisocial behavior that is related to MAOA activity (Huang et al., 2004). Males with a genotype encoding low MAOA enzyme activity were more likely to be convicted of a violent crime than maltreated males with a high-activity MAOA genotype. 

Kandel and colleagues carried out their studies in the giant marine snail Aplysia, because it was possible to examine individual neurons. They found that memory does not reside in specific neurons but in the synaptic connections among neurons, which are augmented or weakened by past experiences. 

Do genes encode altruism Persons inclined to be altruistic rather than competitive are more likely to survive and reproduce. Thus, altruism is a driving force in the process of evolution. Genes related to altruism increase the likelihood of survival of altruistic societies. 

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