biological explanations for offending - forensic psychology

a2 psychology unit 3

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  • Created on: 09-06-12 15:00

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Biological Explanations
Three biological explanations are considered for offending behaviour:
o Genetics
o Chromosomes
o Neurophysiology
It is possible a behaviour determined initially by genetic inheritance in turn influences
Genetic transmission
o Twin and adoption studies have been used to test the heritability of offending
o Concordance rates between MZ and DZ twins were tested
o If offending behaviour is genetic, there should be a 100% concordance rate for MZ
o Studies carried out by Lange and Christiansen found that this was not the case
o To properly assess the influence of genetics, adoption studies must be used:
These involve comparing the criminal futures of adopted children with the
criminal history of:
Their biological parents
Their adoptive parents
This assumes there is greater similarity in the criminal behaviours of the
adoptees and their biological parents that the adoptees and their adoptive
Carey and Goldman found a genetic effect for criminal behaviour
o No single criminal gene has been identified
o There has been an attempt to link criminal behaviour to an extra Y chromosome
o Testosterone has been linked to aggression
o Jacobs et al found that 1.5% of the prison population had the chromosome pattern
XYY, in comparison to only 0.1 % in the general population
o However, this theory is no longer accepted as further studies disproved the results
o There are structures in the brain (specifically, the limbic system and amygdala) that
are responsible for the modulation of aggressive behaviour
o Different regions of the brain have been implicated in different types of aggression
o Adams found that lesions to the ventral tegmental area of the midbrain of rats led to
the disruption of offensive action but did not affect predatory and defensive
o For humans, most neurological research has been carried out on individuals with
Antisocial Personality Disorder (APD), also known as psychopaths
o Studies using EEGs of brain activity found that people with APD had abnormal EEG
patterns of slow-wave activity, typical of brain immaturity
o Hare proposed the maturation retardation hypotheses, suggesting that the brain of
the APD individual is immature and childlike
o This was appealing as the characteristics of APD are:
Inability to delay gratification

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Moffitt suggested that adolescent delinquency might be a result of delayed brain
o However, that does not explain persistent life-course offending
o There are also other neurophysiological anomalies in highly aggressive APD
o Kurland et al found that 66% of APD individuals with a history of uncontrollable and
violent episodes showed spontaneous bursts of rapid brain waves (positive spikes)
during sleep
o APD may also be correlated with Hemispheric dysfunction
o Hare and Connolly suggested that criminals with APD show an abnormal balance…read more


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