biological explanation: genetic and neural Flashcards
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
