Biological Expls for Offending behaviour: FORENSIC PSYCH Flashcards
WHO developed Atavistic form and WHEN
Lombroso 1876
What is Atavistic form
-A biological approach in offending that attributes activity to the fact that offenders are genetic throwbacks
-primitive subspecies which lack evolutionary development so are ill suited to conform to the rules of a modern society.
-This results in them turning to crime.
-Such individuals are distinguishable by particular facial + cranial characteristics which link to a particular type of offence
define the word Atavistic
relating to or characterized by reversion to something ancient or ancestral.
Atavistic characteristics examples
-Narrow, sloping brow
-Prominent jawline
-High cheekbones
-Facial asymmetry
-Dark skin
-extra toes, fingers, nipples
atavistic characteristics of murderers
-Bloodshot eye
-curly hair
-Long ears
atavistic characteristics of Sexual deviants
-Glinting eyes
-Swollen
-Fleshy lips
-Projecting ears
Lombroso’s research
Research into Atavistic form. Examined skulls of 383 dead convicts to 3839 living convicts . Lombroso concluded that 40% of criminal acts were committed by someone with atavistic characteristics
4 main Genetic studies of Criminal behavior
-Twin studies
-Adoption studies
-Candidate genes
-Diathesis stress model
Twin studies
-illustrate importance of genes
-Used to analyse concordance rates
what are concordance rates
the number/percentage of twin pairs who both display a pair of characteristics
if a behaviour is more genetic than environmental, we would expect to find a higher concordance rate between…
Monozygotic twins as they share more of their genetics than Dizygotic twins
What did Christiansen 1977 do
Sample = 3500 pairs of twins from Denmark (all twin pairs born between 1880-1910). Offending behaviour was checked against Daish police records. Found 35% MZ, 12% DZ
Adoptions studies
look at effect of genes on children who are not raised by their biological parents. This means that the environmnet the child grows up in will be different to that of their biological parents
This makes it easier to see whether genes or the environment affect the childs behaviour
what did Crowe do in 1972
Found that adopted children who’s biological mother had a criminal record had a 50% risk of having a criminl record by the age of 18 - whereas adopted children who’s biological mother did not have a criminal record only had a 5% risk
What are Candidate genes?
genes that can lead to a genetic vulnerability to a certain condition
what two Candidate genes are focused on
MAOA Gene
CDH13 Gene
MAOA Gene . what is
-Gene codes for break down of neurotransmitters in the brain
-NT’s allow nerve cells in brains t communicate
-People with low levels of MAOA activity therefore do not break down these neurotransmitters as effectively, result in in higher levels of serotonin which makes aggressive behaviour more likely
MAOA gene :. nicknamed he ‘warrior gene’ bc of its association with high aggression
Women = 2x copies of MAOA gene
MEn = 1x copy
:. Men more likely to commit crime
what si the CDH 13 gene
Another potential MAOA gene
-Responsible for the production of a protein adhesive that sits around membranes in the brain
-Low levels of CDH13 have been linked to substance abuse and alcoholism
Tiihonen et al (2015)
Gathered DNA info from almost 800 Finnish prisoners.
Compared the DNA of prisoners against whether prisoners had committed a violent crime,
Found 5-10% of all severe violent crimes were attributed to low activity in MAOA and CDH13 gene
Diathesis stress model
Behavior is explained as the result of a n underlying vulnerability (diathesis) and a trigger, both of which are necessary for the behavior to be shown. The underlying vulnerability is known as a predisposition
Diathesis stress model in context to Criminality
A person may have biological tendencies towards criminal behaviour, but an environmental trigger is also needed for the person to take part in criminal behaviour. Therefore, the diathesis stress model suggests that criminal behaviour may not be completely explained by biological factors
Three types of diathesis/stress factors
Biological
Social
Psychological
example of biological diathesis factors to criminality
genes, disorders, brain anomalies
example of Social diathesis factors to criminality
maladaptive upbringing, chronic stress
example of psychological diathesis factors to criminality
Maladaptive cognitions, poor skills, unconscious conflictions
example of Social stress factors to criminality
Traumatic events , major loss
example of biological stress factors to criminality
onset of disease, exposure to toxins
example of psychological stress factors to criminality
perceived loss of control
Neural expls of offending behaviour
Any explanation of behaviour in terms of dysfunctions of the brain and nervous system
Pre frontal cortex in criminal behaviour
Part of the brain that regulates emotional behavior.
Brain scans have shown reduced activity in the prefrontal cortex when scanning the criminal brain
Anti-social personality disorder (APD)
Personality disorders and mental health conditions that affect how someone thinks, perceives, feels and relates to others
Characteristics of APD
-Reduced emotional responses
-Impulsive
-Lack of empathy
-Reckless disregard for safety
-irritable
-Aggressive
mirror neurone on criminal behaviour
Special brain cells which fire in both response to personal actions and in response to action on the part of others
Mirror neurones are involved in social cognition allowing us to interpret intention and emotions in others
Research = people with APD can experience empathy but more sporadically than those without
Raine (2000) found
11% reduction in volume of grey matter in the pre-frontal cortex of people with APD compared to controls
Raine also conducted various studies of ADP brain and found
several dozen studies which demonstrate that individuals with ADP have reduced activity in their pre frontal cortex
Keysers Found (2011)
Criminals empathy reaction (controlled by mirror neurones) only showed when asked to
suggests people with APD are not totally without empathy, but may have a neural ‘switch’
