2. gentic factors

Question 1

biological approach

Answer 1

believes aggression is linked to genetics
tries to establsih if genetically related are simmilarly agressive
tries to disentangle offect of nature (genetic inheritance) and nurture (environment)

Question 2

twin studdies
Coccaro et al

Answer 2

compares the degree of similarity between MZ and DZ twins
if aggression is higher in mz= genetic factor not environment
Coccaro et al= adult male mz and dz twins, aggressive behaviour measured by direct physical assault
mz concordance=50% compared to dz= 19%
genetics make up 50% of aggressive behaviour

Question 3

adoption studdies
Hutchings and Mednick

Answer 3

positive correlation in biological and adoptive parents suggesrs a genetic facotr
Hutchings & Mednick: 14,000 adopted in Denmark found genetic influence
found significant number of adopted boys with criminal convictions had parents (mostly fathers) with violent criminal convictions

Question 4

Evaluation
adoptive/twin studies
support
miles and carey
Rhee and Waldman

Answer 4

meta-analysis
24 twin 7 adoption studies
found strong genetic influence
up to 50% variation in aggression

meta-analysis
51 studies showed aggressive and anti-social behaviour largely due to genetics

Question 5

Evaluation
adoptive/twin studies
meta-analysis
limitations

Answer 5

variables: age, method for aggression
impacted genetic influence on aggressive behaviour
suggests other factors affect expression of aggression

Question 6

evaluation
adoptive/ twin studies
miles and Carrey meta-analysis

Answer 6

used self/parental report= social desirability
and observation high variation
observation= more environment impact
self report=genetic
inconsistency= hard to assess genetic vs environmental factors

Question 6

valuation
adoptive/ twin studies
limitation
isolating genetic factors

Answer 6

difficult establishing how influential genes and environmental factors are
someone may have a gene associated with aggression but not the right environment for it to be expressed e.g MAOA

Question 7

MAOA

Answer 7

monoamine oxidas A
produces an enzyme to ‘mop up’ neurotransmitters from nerve impulse transmitted from a neuron by breaking down neurotransmitter
especially serotonin
to be recycled or excreted
dysfunctional means abnormal activity affecting levels of serotonin

Question 7

MAOA
evaluation
supportive evidence
Caspi et al

Answer 7

500 male children
low variant MAOA
less likely to have anti-social behaviour than a higher variant

Question 8

MAOA
evaluation
supportive evidence
McDermott et al

Answer 8

controlled experiments measured actual aggression
MAOA-L meant high levels of aggressive behavior when provoked compared to MAOA-H
links between genetic variation and willingness to be aggressive

Question 9

MAOA
evaluation
genes and the environment

Answer 9

Caspi & McDermott found evidence for gene and environment interaction
MAOA-L = higher anti social behavior IF maltreated as a child
McDermott moderated environment factors, low level activity based on money allocation game, only aggressive when provoked else similar
genetics only significant when environment interacts else not expressed
MAOA is not a complete explanation

Question 10

MAOA
evaluation
supportive evidence
Cases et al

Answer 10

disabled MAOA in x chromosome of mice
without dopamine and serotonin increased
males more aggressive females unaffected
restoring MAOA returned to normal

Question 11

MAOA
evaluation
positive applications

Answer 11

offender treatment in rehabilitation can focus on anti-social behaviour
Morkey and Hall develop treatment for personality disorders
consequence of genetic tests mean criminals can use it as evidence to diminish responsibility