Psychology of Crime
October 3, 2012
Week 4, Wednesday
Famous left handed criminals:
• jack the ripper
• john dillinger
• billy the kid
• the boston strangler
Left hemispehere dysfunction theory
Cerebrum divided into parts
• left and right cerebral hemispehres
• Lateralization: functional specialization in one hemisphere
Contra lateral pathways
Left controls right, right controls left.
Left hemisphere: (dominant for most people)
Language processing and comprehension, math, logic
Creativity, spatial dimensions, imagination.
Reduced functional lateralization for language:
Deficits in left hemisphere activation ersult in problems with language comprehension, processing and
Difficulties in interpersonal encounters (social skills)
Conflict resolution, peer rejection.
Why is handedness meaningful?
Indicator of reduced lateralization
• 95% right handers are left hemisphere dominant
◦ Most (60%) also left hemisphere dominant
◦ 20% are right hemispheres dominant for language
◦ 20% are bi lateral for language (no specialization)*
• Criminals should be more likely to be left handed, since lefty's are more likely to have bilateral
Week 4: THE BAD SEED: evolutionary theory and crime
Genetics and crim behaviour.
Behaviour genetics theory:
Abranch of genetics that studied the relative contributions of heredity + environment to behavioural
and personality characteristics
GENES affect behaviour in interaction with ENVIRONMENTAL influences.
What are genetic markers?
Characteristics of genes that “mark” a locations of genes that may contribute to a trait. Caridovascualr Underarousal
Autonomic arousal theory
Low heart rate and fearlessness
People commit crime because they are looking for excitement b/c they are chronically under aroused.
Agene by Environmenr Interaction:
Criminality more likely when environmental and genetic risk factors occur together
E.g Underaroused ANS + parents who model violence.
Specific behaviours are caused by biological mechanisms that evolved through natural selection.
Changes in population genepool
What traits are desirable/adaptive in today's world?
As the world changes- different traits become more adaptive.
differential survival and reproduction of organisms with genetics characteristics that enable them to
better utilize environmental resources
an individuals genetic fitness is defined in terms of his or her reproductive success or the number of
viable offspring produced.
Can criminal behaviour be adaptive?
Crime is a politically defined construct
Traits that underlie “criminal behaviours” may be adaptive