Aggression: Genetic factors in aggression

Question 1

What are the 2 genetic factors in aggression?

Answer 1

twin studies

the MAOA gene

Question 2

Make 1 point about how twin studies relate to aggression

Answer 2

-concordance rates between MZ and DZ twins have suggested that heritability accounts for aggression

Question 3

Make 4 points about the MAOA gene and how it influences aggression

Answer 3

-the gene codes for an enzyme that breaks down neurotransmitters such as serotonin so they can be reabsorbed
-dysfunction in the gene has an effect on serotonin levels in the brain
-a particular variant known as the warrior gene leads to low levels of MAOA activity
-it is unclear how behaviour is linked to low MAOA activity

Question 4

Who provides contradictory evidence for twin studies?

Answer 4

Cocarro et al 1997 - studied adult male twins and found concordance rates of 50% for MZ and 19% for DZ for physical assault , and 28% for MZ and 7% for DZ for verbal aggressions

the concordance rates were not 100% suggesting genetics are not the only factor involved in aggression

Question 5

Give a further criticism of twin studies

Answer 5

-the study only involved male ppts so lacks population validity , its also hard to isolate the roles of environment from the roles of genetics as twins often share the same environment

Question 6

Give a piece of supporting evidence for the role of the MAOA gene in aggression

Give a however point for this evidence

Answer 6

+ Caspi et al 2002- studied 1037 New Zealand children for 25 years and found high levels of aggression in those with a deficient MAOA gene but only if they also suffered childhood abuse

this evidence suggests genetics are involved

HOWEVER … the evidence suggests there is an interaction between genetics and the environment , so aggression may not be purely genetic

Question 7

Give another piece of supporting evidence for the role of the MAOA gene in aggression

Give a however point

Answer 7

Brunner et al 1993 - studied 5 generations of a very aggressive Dutch family and found all male members carried a rare MAOA mutation which strongly suggests genetics do influence aggression

HOWEVER … its impossible to determine what was due to genetics and what was due to the environment

Question 8

Give a general weakness for the genetic factors in aggression

Answer 8

-other explanations
social psychological explanations , suggests the genetic explanation can’t be considered complete

Question 9

Give a second general weakness of the genetic factors in aggression

Answer 9

-aggressive behaviour is poorly operationalised

methods of measuring aggression differ between studies so if findings differ depending on how aggression is operationalised it becomes very difficult to draw valid conclusions about the role of genetic factors

Question 10

Discuss 2 relevant issues and debates regarding the genetic factors in aggression

Answer 10

-more on the nature side which may lead to underestimating the role of the environment

-very deterministic which has implications on criminality and attributing responsibility as the explanation suggests we have no free will