Biological Criminality

        We can compare the family trees of criminals and non-criminals – if many criminals’ relatives are also criminals, there might be a biological link. Fewer criminal relatives, the weaker the link.

  •  Twin studies monozygotic twins share exactly the same genes.  Christiansen (1977) found that from 3586 pairs of twins if an identical twin was a criminal, 525 of the time the other twin was also a criminal.  In dizygotic twins the rate was only 22%.
  •  Adoption studies – these people share genes but not environment so in these cases we can be sure that genetics are the cause of criminality.

·         Evidence to suggest that individuals are more likely to be criminals if their parents are criminal -

  • It could be that it is nothing to do with genetics at all.  Family members are raised together and treated similarly so therefore their criminal behaviour could be explained by SLT or observational learning.
  •   XYY (male) chromosome abnormality – causes increased aggression, being taller and learning difficulties.
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Social Criminality

  • Family patterns are the experiences children have during their family life.
  • If parents are divorced, individuals are more likely to have criminal tendencies due to factors such as money difficulties, moving house, arguments in the home etc.
  • If children are separated from their main caregiver before the age of 2 years old, this can cause problems in later life – maternal deprivation. (Bowlby)
  • Family size is also an important factor. More than 6 children in a family can result in children being more likely to be criminals.
  • An Australian study by Western (2003) found only a slight link between parental occupation and youth crime.  It seems a father’s occupation was not an indicator but the mother’s occupation did have an effect.
  • It is difficult to pin down exactly which social factors influence criminal behaviour because family circumstances are so complex.  It seems likely that a combination of factors contributes to criminality.  Deprivation from caregivers and bad childhood experiences seem to be factors.
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Child-rearing Criminality

·         The way in which parents bring up their children are known as childrearing strategies.  Dealing with naughty children may involve induction, love withdrawal and power assertion.

·         Induction is where parents explain to their child what they have done wrong and allow them to think about the consequences. Children can then make the right decision the next time.

·         Love withdrawal is when parents put conditions on their love, they don’t love their children when they have done something bad. Results in children being confused about their identity, unsure as to whether they are loved or not.

·         Power assertion includes hitting, shouting at children, humiliating them, grabbing them etc. Can lead to aggression in children.

·         Although this theory seems to suggest parents are solely responsible for producing delinquent children, there are many factors that contribute to delinquency.

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Self-fulfilling Prophecy Criminality #1

  • If we are seen as or expected to be criminal, we will behave in that way – this is an example of self-fulfilling prophecy.
  • This is where a behaviour that is expected of someone will come true.
  • People conform to the behaviour that is expected of them.
  • e.g. If a teacher expects a pupil to do badly in a test, they will not offer them help and focus on others, resulting in the pupil doing badly in the test (the prediction has come true).
  • Rosenthal and Jacobsen (1968) conducted an experiment to test whether achievement could be self-fulfilling.  They gave children an IQ test and then told their teachers which children were going to be ‘bloomers’ and which ones were going to be ‘average’. (this was a lie – it was just a random list of names!)
  • They found that the teachers didn’t expect much of the ‘average’ children and gave all the attention to the ‘bloomers’.
  • The IQ of the ‘bloomers’ rose and the ‘average’ children’s IQ fell.
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Self-fulfilling Prophecy Criminality #2

  • Johoda (1954) studied the Ashanti tribe who had a custom of naming their children after the day of the week they were born on.  e.g. Monday boys were called Kwadwo meaning calm and peaceful whereas those born on Wednesday were called Kwadku meaning aggressive and angry.
  • When he looked at the records of boys arrested he found that 22% of boys were born on a Wednesday with only 6.9% born on a Monday, thus the prophecy became self-fulfilling.
  • Those around them (family, friends, teachers etc.) expected the Wednesday boys to be aggressive and behave badly and treated them differently because of this.
  • Jahoda only found a link between the child’s name and criminality by using a correlation.  It would be very unethical to study self-fulfilling prophecy as a cause of crime by treating someone differently and seeing if it affected their behaviour. It can’t be proved that self-fulfilling prophecy causes criminality.
  • Another weakness of the theory is that many of us reject the way we are treated by others so the prophecy is not fulfilled.
  • It doesn’t take into account the fact that there are many other reasons for crime, ranging from our biology to the families we are raised in.
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Comparison of Biological and Social Theory


  • We inherit the genes that cause criminal behaviour
  • Adoption studies show how crime can be inherited
  • XYY chromosome abnormality may cause aggression in males, leading to violent crime
  • This theory is weakened by the confusion between genetics and upbringing in twin and family studies
  • Chromosome research is limited, as only small samples have been gathered and studied


  • Being brought up in a family that makes criminal behavior more likely
  • Separation from parents can cause distress and mistrust that can affect later development
  • The self-fulfilling prophecy explains how behavior can be influence by the way we are treated and expected to behave
  • This theory cannot separate the influence of many social factors that influence criminality, such as peers and other experiences
  • People often rebel against how they are treated by others; they do not fulfill the prophecies that are made.
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Offender Profiling

  • Offender profiling is a process used to help police catch criminals.  It does not produce the name of the criminal but helps to narrow the number of suspects that police should investigate.
  • A criminal profile is a prediction of what a criminal is like using evidence and psychology.
  • Traditional policing involves the analysis of physical evidence (fingerprints, bloodstains, show prints, DNA etc.) but psychologists believe that the way in which a crime was committed gives additional clues about the criminal.
  • A criminal will leave clues at the crime scene such as: type of victim, type of crime, location, time of day or night, specific features of a crime, what is taken or left behind.
  • There are often similarities between crimes committed by the same person that can be picked out.  The way in which an offender commits a crime is a reflection of their self they will do things that they normally would do in their criminal behaviour - criminal consistency.
  • The profile can help the police predict the type of future victims and offenders.  The profile can give clues about evidence that might be found on the criminal, such as souvenirs taken from the crime scene. It can also suggest very useful interview techniques for the police to use on the criminal. e.g. a clever criminal will not talk if interviewed in a severe way.
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Creating an Offender Profile

  • 1. Analysis of the crime – the police make detailed records of the victim, place, photographs, DNA evidence and time of day.
  • 2. Building a profile – a criminal profiler uses this information to construct a list of probable features of a criminal
  • This can include age, race, sex, marital status, occupation, intellectual ability area lived in, previous criminal activity.
  •  A handful of profiles have been successful but others have led to victimisation and entrapment.
  • Colin Stagg was arrested for the murder of Rachel Nickell (1992) based on a profile by Paul Brittan. There was no physical evidence against him but because the police thought he was the right man, he was followed by the media and police and made an outcast.
  • In 2008 Robert Napper pleaded guilty and Stagg was given an apology from the police.
  • Many people argue that offender profiling is nothing more than experienced guesswork.
  • Offender profiling is just one of the many links in the chain that police use to catch criminals. It is unfair to blame the profile for failing to catch the criminal.
  • Most police officers believe that profiles are useful, but that they do not always help solve the crime.  Traditional policing is still the most effective way of catching criminals.
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John Duffy Case

  • David Canter is a famous forensic psychologist who produced profiles of offenders.
  • The profile of John Duffy was very close to what they offender was actually like.
  • Canter reasoned that Duffy tied his victims up because he was not a strong man.  Because he was small he was able to approach them without them seeing him as a threat
  • Duffy was arrested on 7th November 1986 and convicted of 3 murders and 7 counts of **** and sentenced to 3 life sentences.  He also revealed he had an accomplice, David Mulcahy (his school friend) committed some of the crimes with him.
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Forensic Psychologist

•Works in the courts to uncover psychological issues

•looks at psychological aspects of criminal activity

•Sets up treatment programmes and evaluates them

•Making offender profiles

•Working with prisoners to assess the threat to staff etc., working with victims and witnesses

•Research and reviewing data

•Give evidence in court and advise parole boards

•Working with other agencies, assessing problems, coming up with interventions and developing policy

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Becoming a Forensic Psychologist

  • Qualifications:
    • Degree in psychology
    • Work experience
    • Masters in Forensic Psychology (step 1 of the Diploma in Forensic Psychology)
    • 2 years supervised practise (step 2)
  • Skills:
    • Communication – listen carefully and speak comfortably
    • Good writing skills
    • Problem-solving skills
    • Understand body language
    • Be able to work within the BPS ethical guidelines
  •  Who do they work for?
    • HM Prison Service
    • NHS
    • Social Services
    • Self-employed
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Forensic Psychologist Treatment (Sexual Offenders)

Treating sexual offenders

  • It is mandatory that sex offenders attend a treatment programme
  • What causes sex offending? If we know what causes it, we can treat it but we cant be sure what causes it.
  • Medication can be prescribed to reduce sex drive
  • Cognitive Behavioural Therapy (CBT) involves helping someone to change how they think about something and therefore behave differently.
  • Negative thoughts are changed to positive ones.
  • Intimacy problems poor childhood relationships can lead to loneliness or a lack of skills in intimacy.  Offenders may have a distorted view of what is appropriate behaviour.
  • Social skills problems child molesters tend to lack confidence and have difficulty mixing socially.
  • Problems with empathy sex offenders seem to confuse fear, anger and disgust, finding it hard to separate these emotions.
  • Cognitive distortions if the sex offender has distorted thinking, they can justify their behaviour to themselves. 
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Forensic Psychologist Treatment (Personal, Drug Ab

Personal Construct Therapy

  • A therapy where someone finds their own way of looking at people (their personal constructs) and uses their constructs to see how they judge the people they know.
  • The psychologist helps the person to understand their own constructs and then repeats the task later to help them see how they have changed.
  • After some intervention by the psychologist, (e.g. social skills training) the individual judges their own constructs again to see what changes have been made during treatment.

Treating drug abuse

  • Prescribing substitute drugs and monitoring the addicts progress closely and providing support and counselling.
  • Making sure they have adequate housing and funding to prevent them turning back to drugs.
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Characteristics Affect Jury Decision-Making (Info)

  • Serious criminal offences are dealt with in a court of law, with a judge and a jury (12 randomly selected people from the local area)
  • During the trial the jury listens to the evidence and testimony presented by the defence (those who are supporting the defendant’s innocence) and the prosecution (those who are trying to prove that the defendant is guilty).
  • The jurors then talk to each other in private before making a decision.  A guilty verdict results in the judge deciding upon a sentence.  Sometimes however, innocent people are sent to prison or guilty people are released due to an imperfect system.
  • Can juries make mistakes?  Their decision should only be based on what they have seen and hear in the courtroom – the evidence - but jurors might be affected by other factors.
  • How a defendant looks, acts or sounds affect how they are viewed by a jury.  We base our decisions on the stereotypes we hold.
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Characteristics Affect Jury Decision-Making

  • Race
    • There is a higher proportion of ethnic minorities in prison (15%) than in the general UK population (8%)
    • Skolnick and Shaw (1997) found that the relationship between the race of jurors and the race of defendants were both important in the decision-making process.  Both black and white jurors were less likely to find a black defendant guilt (this goes against other studies), and that black jurors were more likely to find a white defendant guilty than a black defendant.
  • Attractiveness
    • Taylor and Butcher (2007) conducted a mock jury study and found that more attractive people were judged as less guilty of a crime and given lower sentences than unattractive people. 
  • Accent
    • If a defendant is well-spoken, we are less likely to find them guilty of burglary.
    • A defendant with a strong regional or ‘rough’ accent (e.g. Geordie, Scouser etc.) may be more likely to commit a crime. (Mahony and Dixon, 2002) 
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