biological explanation: genetic and neural Flashcards
(23 cards)
twin studies
the concordance rate of twins for criminal behaviour gives us an indication of the extent that offending behaviour could be inherited
twin studies: Christiansen 1977
MZ : 35%
DZ: 13%
sample size: 3586 twins in Denmark
A03: TS-concordance rate isn’t 100%
so interaction between environment + genetics together produces outcome of criminality- suggested also by medick et al (1984) adoption study
Twin studies: Raine 1993
MZ:52%
DZ:21%
Sample size:review of 13 studies
candidate genes- Tiihonen et al 2014
-MAOA gene ‘warrior gene’
-CDH13 (code for neurotransmitters such as D+S) ‘associated w/ ADHD + substance abuse’
-800 Finnish offenders tested for gene
-5-10% of all violent crimes in Finland attribute w/these genotypes
Diathesis stress model
-cup analogy
-if genetics play a part its also likely their affected by environment
-crime behaviour come about through combination of genetic predisposition + biological/psychological trigger
DTSM: support-mednicks et al (1984)
-analysed 14,427 adoptees + records of adoptive n biological parents
-“siblings adopted separately into different homes tended to be concordant for convictions, especially if the shared biological father also had a record of criminal behaviour”
- however, cannot rule out SLT as highest conviction rate was when both bio n adopt parents had been convicted = 24%
serotonin
neurotransmitter linked to mood + impulsiveness
low serotonin = no self control
serotonin study- Moir + Jessel 1995
used animal+human studies that suggest link between low levels of serotonin + aggression
-link to criminal behaviour
serotonin study: scerbo + raine 1993
-meta analysis on 29 pieces of research on antisocial ppl
-low level of serotonin in all cases
dopamine
link to pleasure
-desire to repeat certain behaviours
-link to addiction+ substance abuse
-indirect link to crime
dopamine study: buitelar 2003
-juvenile delinquents given dopamine antagonists which reduce levels of dopamine
-show decrease in aggression
dopamine study: couppis 2008
-some criminals may experience increase in dopamine + as result seek out experiences again due to reward feeling
frontal lobes
-part of the neocortex has been linked to higher function such as social behaviours + planning
fl: bower + ptice 2001
found link between FL dysfunction + violent crime
fl: kendel + freed 1989
FL damage + antisocial behaviour are linked
KEY: Antisocial personality disorder- raine et al 2000- procedure
-aim:identify regions specific to offenders charged w/ murder or manslaughter, who had pleaded not guilty by reason of insanity
-method: 41 murders + 41 non murderers, PET scanning, matched pairs, Their brains were scanned 10 times at 10 minute intervals to pick up differences in glucose metabolism in the cerebral cortex and sub-cortical layers
Raine et al 2000 findings
-results: reduced activity in prefrontal cortex (logical thinking + decision making)+corpuscallosm. abnormalities in activity of limbic system-amygdala
amygdala
-part of limbic system
-linked w aggression+ emotion regulation
AO3: limitation of Raine study
-faulty functioning could be due to trauma. not everyone w injury could be criminal
-cause+effect is unclear, doesn’t affect people w brain physiology in same way
-brain functioning issues might be due to a physical abuse in childhood
-small sample size-genersalised low
AO3:neurotransmitters
-biochemical explanations are relevant to everyday life
-caused by mental illness
-research on neurotransmitters is conducted on animals+might not be valid for people
-redutionists + don’t take in condition of other factors + complexity of influence on human behaviour
AO3: biological reductionism: katz et al (2007)
-though criminality runs in families so do other risk factors associated w/criminality (eg deprivation)
-stereotyping these children may lead to self fulfilling prophecies
support 4 raine- Keysers et al 2011
humanity switch
-criminals have neural switch use to turn capacities for empathy on or off.
-lack empathy for victims
