For criminological psychology, you need to be aware of the following biological and social explanations for criminality.

Biological Explanations for Criminality

Brain Injury

  • Injury to the brain can lead to personality and behaviour changes.
  • (+) Phineas Gage
  • (+) Williams et al (2010) asked 196 criminals.
    • 60% reported brain injury
    • Adults who reported brain injury also
      • Were in prison from a younger age
      • Had higher recidivism rates.
  • (-) Kreutzer et al (1991)
    • There seems to be a correlation between brain injury and criminality but not when you take out other risk factors such as substance abuse, then there is no correlation.


Emotional center of the brain, part of the limbic system.

  • (+) Pardini et al (2014)
    • People with psychopathic symptoms generally had smaller amygdalae.
    • People with smaller amygdala were 3x more likely to be aggressive.
  • (-) James Fallon
    • Is a psychologist who can identify psychopaths using brain scans fairly accurately.
    • Unknowingly identified himself as a psychopath, but he’s not one.
    • This shows that although biology plays a role, the envionment must have some influence.

Raine et al (1997)

  • Found that NGRIs had:
    • Lower activity in prefrontal cortex (associated with impulse control)
    • Lower activity in corpus callosum (2 hemispheres weren’t communicating effectively)
    • Different activity in amygdala and hippocampus than controls. (emotional and learning centres respectively).

XYY Syndrome

  • Occurs in 1/1000 births.
  • Male is born with 2 Y chromosomes.
  • Normally:
    • Grow faster and taller
    • Slightly less intelligent, but still within a normal range
    • Easily distracted.
    • Have behavioural problems.
  • (+) Theilgaard et al (1984)
    • XYY men are slightly overrepresented in prisons.
    • They have generally lower intelligence
      • She theorised that their learning difficulties caused their criminality.
  • (-) The extent of XYY in prison populations is unknown due to the resource intensive nature of collecting genetic data.

Sham Rage

Uncontrollable rage to no stimulus. It’s found in animals such as cats.

(+) Cannon & Britton (1925)

  • Ablation of the amygdala leads to lack of emotion.
  • Stimulation of the amygdala leads to sham rage.

(+) Narabayashi et al (1963)

  • Severing link between amygdala and the rest of the limbic system in humans led to lack of emotion.

(-) Much of the evidence is on animals and therefore not generalisable to humans, especially because humans can control rage with higher level thinking, unlike most animals.


Eysenck came up with a personality theory.

  • Personality is split into:
    • Extraversion/Introversion
    • Neuroticism/Stability
    • Psychoticism
  • Criminals often have the PEN type according to Eysenck.
  • Arousal Theory (Biological explanation)
    • The Ascending Reticular Activating System (ARAS) needs to be stimulated
    • Extraverts have little stimulation to the area, so need external stimulation.
    • Introverts have lots of stimulation to the area.
    • Psychoticism explained by low MAO and high testosterone levels.
  • (+) / (-) Farrington et al (1982)
    • P and N scores correlate with criminality, not E.
  • (+) / (-) Boduszek et al (2013)
    • E scores correlate with recidivism.


Low serotonin = Higher aggression levels

High dopamine = Higher aggression levels. (Lavine, 1997)


Higher testosterone  = Higher aggression (Albert et al (1986) castrated mice and this reduced attempts to show social dominance)


Most of these explanations don’t directly talk about crime, they talk about aggression, which doesn’t necessarily mean crime, and lots of crime isn’t even caused by aggression (Even violent crime, like hitmen). Therefore, these may be seen as explanations for aggression, and not necessarily explanations for criminality.

Social Explanations for Criminality

Self-Fulfilling Prophecy & Labelling

Labelling – Defining a person using broad terms.

Self-fulfilling prophecy – A label which causes somebody to act according to the label.

(+) Rosenthal & Jacobson (1968)

  • Labelled some children in a classroom as ‘bloomers’ (academically gifted), told the teachers and then tested them a year later.
  • Found that the ‘bloomers’ did much better on the test than the control group.
  • This was due to the teachers treating the children differently and leading to the self-fulfilling prophecy due to the bloomer label.
  • However, it used IQ tests which are criticised for not measuring intelligence completely, for example lacking in practical intelligence.

(+) Jehovah (1954)

  • Studied the Ashanti people in Ghana
  • They are named after the day of the week they’re born.
  • Monday = calm and nonaggressive
  • Wednesday = aggressive
  • Found that 22% of violent crime convictions were by people born on Wednesday, 6% by those born on Monday.
  • People born on Wednesday were treated differently as they were expected to be more violent, leading to the Self-fulfilling prophecy.

(-) However, not much research on criminality as it’s unethical.

(-) Much of the research is correlational, therefore no cause and effect can be established.

Social Learning Theory

It’s a Social-Cognitive Theory, and is a developmental explanation.

Criminality is due to seeing and modelling behaviour.

(1) Attention – Learn the crime by seeing people commit it either in real life or on TV.

(2) Retention – Remember the crime after seeing it.

(3) Reproduction – Reproducing the crime.

(4) Motivation – Motivated thanks to crime often being sensationalised on TV.

(+) Williams (1986)

  • TV introduced to isolated community
  • Measured aggression in a longitudinal study in young people.
  • Those exposed to TV were 2x as aggressive as controls.
  • (-) Williams points out that increased violence may be due to materialistic life.

(+) Bandura.

(-) Social class may be a cause of violence, not media as those in the lower classes generally watch more TV and are therefore exposed to it more, and are more likely to be criminals.

(-) SLT states that behaviour is not repeated if there is a negative consequence, but repeat offenders contracdict this.