genetic explanations to aggression
Twin studies
• coccaro et al
• compared degree of similarity for aggression
• monozygotic twins showed 50% concordance rate for aggressive behaviour
• dizygotic twins showed 19% concordance rate for aggressive behaviour
• shows genetic link as MZ concordance rate much higher than DZ concordance rate
MAOA gene
MAOA gene -> responsible for production of monoamine oxidase (MAOA enzyme) -> breaks down neurotransmitters in brain (Eg: serotonin, dopamine) -> these neurotransmitters have been linked to aggressive + impulsive behaviour
MAOA-L
• low activity version of the gene
MAOA-L -> low monoamine oxidase -> high levels of neurotransmitters (Eg: serotonin, dopamine) -> high levels of aggression