Biological theories of criminality. Flashcards
What are the types of biological explanations for criminality?
Physiological theories
genetic theories
neural theories
biochemical theories
Lombroso’s Atavistic features?
Lombroso believed that criminals were ‘genetic throwbacks’
Examined facial and cranial features of 383 convicted criminals who were deceased and 3839 living ones
Concluded that 40% of criminal activity could be accounted for by atavistic features.
what are some atavistic features?
large jaw
high cheekbones
handle shaped ears
exceptionally long arms
large eye sockets
swollen fleshy lips (sexual sadists)
thin lips (murderers)
aqualine noses (murderers)
Sheldons somatotypes?
Ectomorphs - slim and tall
Endomorphs - heavy and rounded
Mesomorphs - Build muscle (strong and solid)
Mesomorphs and endomorphs are more likely to commit violent and aggressive acts. Ectomorphs criminal behaviour of sexual acts
Sample size of 200
Jacobs (1985) XYY theory?
- XYY or ‘supermales’ are reported to be more aggressive and violent than XY males.
- They tend to be stockier in build, and have lower levels of intelligence
- supermales are 15/1000 in prison populations compared 1/1000 in the general population
- serial killer John Wayne Gacy is said to possess the XYY defect.
Nature and nurture for John Wayne Gacy?
Nature: XYY, heavy birth weight/overweight as a child, alcoholism of parents suring/before/after pregnancy, early desire to be a female, homosexuality
Nurture: rejection/abuse (both emotional and physical) from father, bullying from peers, sexual deviance (wore mothers lingerie), closeted homosexual.
What is the MAOA gene?
the ‘warrior’ gene which controls serotonin and dopamine (Bradely Waldroup case). This may be present in as much as 40% of the population.
Research on twins?
Lange (1929): studied 13 sets of MZ twins and 17 sets of DZ twins. 10/10 MZ twins had both served time in prison vs. only 2/17 sets of DZ twins had the same concordance.
Christiansen (1977): studied 3586 twin pairs from the Danish Islands. Found concordance rates for criminal behaviour in 35% of MZ twins and 13% of DZ twins.
Adoption studies?
Mednick et al. examined data on over 14000 adopted sons . They found a concordance rate of 20% for having criminal record shared between biological parent and child.
By contrast, only 14% of children had a criminal record if their adoptive parent had on.
Adoptees with criminal birth parents were more likely to have a criminal record than adoptees with criminal adopted parents.
Case study: Charles Whitman?
Killed 16 including his mother and his wife then went to the uni of Texas and shot more people. He left a note for when he died and Whitman requested an autopsy be performed to determine if something had changed in his brain.
Whitman had a brain tumour pressing on his amygdala.
What is the role of the amygdala? What is the consequence of impairment?
- Emotional processing, known as the ‘fear centre’, detects threats and sends messages to the hypothalamus to begin the fight or flight response.
- impaired decision making, decreased fear response, irrational reaction to threat, increase in aggression - unable to process emotions properly
What is the role of the hippocampus? what is the consequence of impairment?
- long term memories, learning and information processing, works with the motor cortex to enable spatial awareness and navigation skills
- memory loss, unable to form new memories, effect spatial memory or the ability to remember locations, directions and orientation. Impaired learning and judgement - unable to process information properly, may cause an irrational response.
What is the role of the thalamus? what is the consequence of impairment?
- regulates consciousness , sleep and alertness, impulse control and emotional reactions
- insomnia, attention loss, apathy, behavioural and cognitive changes, motor impairments.
what is the role of the hypothalamus? what is the consequence of impairment?
- regualtes homeostasis, inclusing sexual bahaviour and emotional regulation, triggers the SNS to begin the fight or flight response, releases adrenaline into the bloodstream.
- fatigue/insomnia, inappropriate sexual behaviour, infertility - may lead to sexual deviance, inappropriate aggressive response to a perceived threat.
what is the role of the orbitofrontal cortex? what is the consequence of impairment?
- responsible for higher order, critical thinking, impulse control and self-regulation. brings the body back to a calm state after a fight or flight response.
- impulsive behaviour, aggressive behaviour, lack of empathy or concern for others.
