Forensics - Biological Explanations of Offending Behaviour Flashcards
what is the atavistic form?
proposes that criminals are a subspecies of genetic throwbacks that cannot conform to rules of modern society
distinguishable by facial and cranial characteristics
why did lombroso think that criminals were different to the rest of the population?
he said they lacked evolutionary development
what facial characterstics were associated with criminals?
strong and prominent jaw
facial asymmetry
high cheekbones
what bodily characterstics were associated with criminals?
dark skin
extra toes, nipples or fingers
what characteristics did lombroso say that murderers have?
bloodshot eyes
curly hair
long ears
what characteristics did lombroso say that sexual deviants have?
glinting eyes
swollen/fleshy lips
what characteristics did lombroso say fraudsters have?
thin and reedy lips
what did lombroso suggest should happen to genetically ‘unfit’ people?
they should be prevented from breeding
what is the atavistic form based on?
research on post-mortem exams on criminals and studying the faces of living criminals
what are the disadvantages of the atavistic form?
gender bias - theory reflects views on women at the time, beta bias and androcentric research
no control groups to compare criminals to
cultural bias - most characteristics are specific to non-white people - beta bias
what are the advantages of the atavistic form?
first form of criminology - inspired future research
which 2 genes have been found to help cause criminality?
MAOA
CDH13
what is the function of the CDH13 gene?
lows down axon growth when neurons change structure or type
slows down the natural death of vascular cells around neurons during periods of stress
why does the CDH13 slow down axon growth?
helps conserve energy and speed up the change of neurons
why does the CDH13 gene slow down cell death during periods of stress?
natural defence against harmful stress
what form of the CDH13 gene is present in criminals?
a high activity form
what effects does a high activity form of CDH13 have?
interrupts building and strengthening of some neural networks during their development
some networks less well developed or connected
what causes a high activity form of the CDH13 gene?
childhood stress/trauma can affect the gene via epigenetics
what is the function of the MAOA gene?
produces MAO-A enzymes
what is the monoamine hypothesis?
monoamines are broken down by enzyme MAO-A
if MAOA gene damaged, enzyme is not produced so too high levels of monoamines
unable to control impulse control
what are monoamines?
a group of neurotransmitters
eg serotonin, noradrenaline, dopamine
why are men 2x more likely to experience effects from a damaged MAOA gene?
if you have 1 copy of the gene - no effects experienced
gene exists on X chromosome
women 2x more likely to have a functioning form of the gene
what is an example of a study that supports the monoamine hypothesis?
brunner et al
what was the aim of Brunner’s experiment into the MAOA gene?
to explain the behaviour of a large family where the males are affected by borderline mental retardation and abnormal violent behaviour
what was the method of Brunner’s experiment into the MAOA gene?
examination of male family members, including behaviours, and compare to female family members
which abnormal violent behaviours were found in Brunner’s study?
sepeated episodes of aggressive + violent behaviour
sleep disturbances + night terrors
inappropriate sexual behaviour towards female relatives
arson
what were the findings of Brunner’s study?
all affected males had a mutated form of the MAOA gene
all affected males mentally retarded, only one completed primary education
what are some advantages of brunner’s study?
objective study - used DNA - valid as no investigator bias
applications - allows for development of treatments for mutated MAOA gene
what are the disadvantages of Brunner’s study?
correlational not causation
unethical to label people with the mutated gene as potential criminals - could lead to self fufilling prophecy
generalisability - 1 family in netherlands
gender bias - can only explain males
reductionist - doesn’t account for social factors or diathesis-stress - link to nature/nurture
what were the findings of an adoption study into genetics causing criminality?
roughly:
13% criminal children with no criminal parents
15% criminal with at least 1 criminal adoptive parent
20% criminal with at least 1 criminal bio parent
25% criminal with at least 1 criminal bio + adoptive
what is the diathesis-stress model for genetics and criminality?
if someone is genetically predisposed AND experiences stress/trauma, it will lead to criminal behaviour
what is the neuroanatomical explanation for criminality?
damage to prefrontal cortex or amygdala can cause criminal behaviours
what is a case study that shows the role of the frontal lobe in criminal behaviours?
case of Phineas Gage
what is the case of phineas gage?
had a metal bolt through skull and prefrontal area of his brain
recovered physically but drastic personality change from quiet and sober to violent drunk
what does the case of phineas gage conclude about the role of the prefrontal lobe?
keeps behaviour in check
moderates impulses
what role does the amygdala play in criminal behaviours?
amygdala linked to emotion
psychopaths lack empathy, remorse or guilt due to a damaged amygdala
what research supports the amygdala affecting criminal behaviour?
18% volume reduction of amygdala in people with antisocial personality disorder compared to a control
what are mirror neurons?
type of brain cell that fires when you do an action, and when you watch someone else doing the same action.
how are mirror neurons linked to criminal behaviours?
research shows mirror neurons only activated when asked to empathise
in control always active and always empathising
what are the advantages of genetic explanations of criminality?
reliable
lots of research support
objective not subjective
applications to genetic treatments
what are the disadvantages of genetic explanations for criminality?
reductionist - can’t explain non-violent crimes
reductionist - doesn’t account for diathesis stress
determinist - not everyone with the genes will become a criminal
what are the advantages of neural explanations for criminality?
applications for treatments - ecological validity
objective research
what are the disadvantages of neural explanations for criminality?
determinist - not everyone with these abnormalities will become criminals
reductionist - ignoring diathesis-stress
based on research into aggression not offending behaviour
correlation vs causation
