genetic factors in aggression

Question 1

explain twin studies?

Answer 1

• Coccearo study into male mono/diozygotic twins found that although most twins would have been raised together mz twins have nigher concordance rates
• physical aggression MZ=50% DZ=19%
• shows heritability is a large factor in aggression

Question 2

explain adoption studies?

Answer 2

• Rhee and Waldman carried out meta analysis of adoptions tidies on aggression
• found genetic influence of biological parents = 41%
• similar to twin studies

Question 3

explain a weakness of adoption studies?

Answer 3

• this study showed genetic factors have have greater influence on aggression using self report methods rather than parent/teacher reports
• if findings vary on type of measurement it is difficult to draw valid conclusions about role of genes

Question 4

explain the influence of the a faulty MAOA gene?

Answer 4

-a dysfunction in this gene may lead to abnormal activity of the MAOA enzyme= affects levels of serotonin in brain

Question 5

what is a MAOA gene?

Answer 5

-enzyme that mops up neurotransmitters in the nerve after a nerve impulse has been transmitted into chemicals to be recycled or Secreted out

Question 6

evaluate study that supports the impact of a dysfunctional MAOA gene?

Answer 6

• studied 28 males from one family who were active in violent behaviours eg.rape
• found that these men had very low levels of MAOA gene in brain and
• supports how low MAOA and low activity variant gene can led to aggression

Question 7

evaluate study that claims there are multiple genetic influences to cause aggression not just MAOA?

Answer 7

• study into intimate parter violence was associated with not only low activity variant of MAOA gene but serotonin transporter gene
• meta analysis couldn’t find an association between one gene and aggression = there are hundred of genes that can determine aggression
• limitation of reductionist approach

Question 8

explain the MAOA gene for gene-enviornment (GxE) interactions

Answer 8

• MAOA gene activity only related to adult aggression when paired with early traumatic event. shows aggression doesn’t function in isolation
• supports gene-environment interaction

Question 9

evaluate a weakness of (GxE) interactions?

Answer 9

• hard to separate genetic and environmental factors as they may have the aggressive gene, but behaviour may only be expressed if environment is favourable
• supported by money allocation game