Biological explanations of aggression

• Selective breeding = higher levels of aggression in animals.

• Genetic mutution nicknamed 'fierce' gene attributed to viloent behaviour in mice.Supports biological explanation as it shows its possible to pass on aggressive traits genetically

Low generalisbilty: limitations as to how far it can hep us understand aggressive bahviour in humans.

(I) Biological Approach

(J) aggression result of genes

(I/A) Those with gene end up marginalised

(I) Determinist

(J) aggressive because of genes

(I/A) free-will disregsrded, reduces individual responsinility.Individual convicted of violent crime easily freed on the basis that conduct was out of their control, they are not to blame.

(I) Reductionist

(J) reduce complex behaviour to genes

(I/A) Ignores social factors that can prompt or influence onset of aggression. But current research says there isnt a gene per se for aggression. Adopts more interactionist outlook.

(I) SSR

(J) Ethical concerns. Individual labelled aggressive is threat to society.

(I/A) Marginilisation may affect wellbeing is unethical if aggressive behaviour not simply determined by genes. E.g 1960's inividuals with 'xyy' chromosome pattern hospitalised. Take care when publishing findings be aware of the implications.

(I) Beta Bias

(J) Much research involves males, thus cannot be generalised to wider population.

(I/A) Biological make-up may make males naturally inclined to aggression than females. As they have more testosterone.

• Miles and Carey meta analysis of 24 twin and adoption studies found genetic influence accounted for 50% of aggression.

Meta analysis: accurate overall view

Validity: mode of assessment large moderator of aggressive behaviour, Parental or self- report used genetics contibute more to aggression. When observational techniques used, environmental factors seemed to influence aggression.

Social desirability helps explain contradictory findings. Parents more likely to state aggression result of child's gentic makeup this way reduces individual responsibility.

• identified gene involved in production of protein monoamine oxidase A (MAOA) which regulates levels of serotonin in brain.

• Researchers associated MAOA with onset of aggressive behaviour. violent behaviour only occurs when interacting with environment

• Support from Caspi et al, who found individuals with high levels of MAOA exhibited anti-social behaviour when maltreated.

Findings support interactionist approach. More favourable outlook than to assert there is specific gene for aggression.

• Research in 1960's identified link between aggression and those with gentic disorder whereby males have extra chromosome y.

Gender Biased: Male participants. Problematic as men and women differ physiologically (Beta Bias). Males have higher levels of hormone testosterone found to contirbute largely to aggressive behaviour. Males may be more naturally inclined towards aggressive behaviour. Not representative of wider population.

• Researchers compare degree of similarity for particular trait between monozygotic twins (MZ)  to similarity between dizygotic twins (DZ)

• Both sets share environment, so differences lie in genes.

• Adoption studies asses contribution of genes to aggression. Looking at whether aggressive behaviour correlates to that of biological or rearing families.