Forensic Psychology Studies

Break downs of the forensic psychology studies we were taught in A2 Psychology. 

These include studies from the sections: Turning to Crime, Making a Case and Reaching a Verdict.

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Disrupted Families


  • Background: It is impossible to completely separate biological and environmental causes from each other.
  • Aim: Documenting the start, duration and end of offending behaviour
  • Participants: 411 boys aged 8 or 9, 6 state schools in East London, white working class. 93% alive at the age of 48 interviewed.
  • Methodology: Longitudinal, quasi experiment
  • Procedure: Interviews of the males over 24 years
  • Results: A peak of 11 offenders per 100 men at 17 years. 10 - 13 and 14 - 16 starters committed 77% of all 808 crimes. Chronic offenders are daring, are more likely to have a young mother, convicted parent and a disrupted family.
  • Conclusion: Offenders are deviant in many areas for example alcohol and drug misuse and aggression. Early intervention should be established for the more important factors such as family criminality, poverty and poor school performance.
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Learning from Others


  • Background: Adopts a behavioural approach taking into consideration operant and classical conditioning as well as the social learning theory.
  • Aim: The theory of differential association.
  • Theory Factors: 
    • Criminal behaviour is learnt
    • It is learnt through interaction
    • The principle learning occurs within intimate personal groups
    • They learn techniques, motives, drives, rationalisations and attitudes
    • Definitions of the legal code are outlined as favourable or unfavourable
    • Differential association occurs, differing in frequency, duration, priority and intensity
    • The learning of criminal behaviour is normal 'behaviourism'
    • There are more or stronger definitions favourable to law violation that unfavourable ones
    • Offending behaviour is an expression of, but not explained by, general needs and values.
  • Conclusion: The definition of a situation where the individual thinks it OK to violate a law is acquired through past experiences.
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Poverty and Disadvantaged Neighbourhoods

Wikstrom and Tafel

  • Background: Socio-economic deprivation is a plausible excuse for offending behaviour, however it does not account for individual differences
  • Aim: Cross sectional study of why young people offend
  • Participants: 2000 year 10's
  • Methodology: Cross sectional study
  • Procedure: Official records and interviews used to collect data
  • Results: 44.8% male and 30.6% females had committed a crime. 9.8% male and 3.8% female had thieved. Offenders were victimised more than non-offenders. Explanatory factors include: social position and situation, characteristics, lifestyle and the community they live in.
  • Conclusion: Propensity induced (personality type), lifestyle dependent (often depends on the activities of their peers) and the situationally limited types (occasional offences often aligned with substance abuse).
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Criminal Thinking Patterns

Yochelson and Samenow

  • Background: There is much debate around the freewill vs determinism argument with regards to this explanation of turning to crime. Many criminals make a plea of diminished responsibility on the basis that their cognitions are 'faulty'.
  • Aim: To understand criminal personalities, techniques used to change personality to prevent criminal behaviour and encourage legal responsibility.
  • Participants: 255 male prison inmates, around half in a secure hospital and half in a prison.Various backgrounds and races etc.
  • Methodology: Longitudinal, quasi experiment
  • Procedure: Interviews conducted with the offenders over 7 years, only 30 completed the programme and 9 changed as a result of it. No control group was used.
  • Results: 52 different thinking patterns were established, these were outlined as not 'faulty' cognitions but simply patterns that are more frequent in criminals
  • Conclusion: Criminals set themselves apart from others, want an exciting life, feel no obligation, lack empathy and are habitually angry and restless.
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Moral Development


  • Background: Piaget conducted much research into this area, in the UK children are said to have fully developed morals by the age of 10
  • Aim: Stages in moral development in children
  • Participants: 58 boys aged 7, 10, 13 and 16. All working and middle class from Chicago
  • Methodology: Self-report
  • Procedure: 2hr interview where 10 moral dilemmas were given (including the Heinz dillemma), these were conducted every three years up to the age of 30 - 36 years.
  • Results: Kohlberg's Stages of Moral Development were formed, younger boys were found to be at stages 1 and 2, older ones at 3 and 4. No stage 6 was actually found.
  • Conclusion: Support across cultures for the theory, criminals are thought to have a moral development at a lower stage. 
    • Levels of morality:
      • 1. Pre-conventional 2. Conventional  3. Post-conventional
    • Stages of orientation:
      • 1. Punishment and obedience,  2. Hedonistic
      • 3. Interpersonal concordance,  4. Law and order
      • 5. Social contract,  6. Universal ethical
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Social Cognition

Gudjohnsson and Bownes

  • Background: Much like locus of control, attribution of blame can be internal or external, or a mental element (a mental illness for example)
  • Aim: Attribution of blame and type of crime committed
  • Participants: 20 property offenders, 20 violent offenders and 40 sexual offenders. Northern Ireland.
  • Methodology: Quasi experiment, self report
  • Procedure: 42 item Blame attribution inventory used for the type of offence and the 3 dimensional attribution (internal, external and mental element)
  • Results: Sexual offenders showed more guilt and the lowest external attribution. Violent offenders had the highest external attribution. There was little difference in the mental element of all. Cross validation conducted with England. Irish violent had a higher external attribution and a lower mental element and guilt.
  • Conclusion: A strong consistency with earlier findings. The difference in the Irish violent offenders and the English may be due to the 'troubles' of the 1980's and early 90's.
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Brain Dysfunction


  • Background: Lombroso concluded that criminals often had visible physical defects. Sheldon hypothesised that they had mesamorphic body shapes. 
  • Aim: The development of antisocial and aggressive behaviour in children. To take a multifactoral approach with a biological focus.
  • Participants: Review article of brain imaging, psychological and neuropsychological research. 
  • Methodology: Review article
  • Procedure: Review article
  • Results: Low resting heart rate and low activity in the still forming pre-frontal lobes is indicative of criminality. Birth complications, smoking during pregnancy and physical abuse may also be contributing factors. 
  • Conclusion: Early intervention and prevention may reverse biological deficits that pre-dispose antisocial and aggressive behaviour. 
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Genes and Serotonin


  • Background: Price found that some offenders of violent crimes were 'supermales' with an extra Y chromosome. Christiansen found a higher criminal concordance between monozygotic than dizygotic twins.
  • Aim: A study of violence in a family with a genetic abnormality
  • Participants: 5 affected males in the Swedish family with a point mutation on the X chromosome of the gene responsible for MAOA.
  • Methodology: Quasi experiment
  • Procedure: Analysis of urine samples over 24 hours
  • Results: A disturbed monoamine metabolism and deficit of the enzyme MAOA.
  • Conclusion: The deficit of MAOA is likely to have caused the metal retardation and may be accountable for the abnormal levels of violence. The phenotype is the inability to regulate aggression, not all retarded males obtained this phenotype.
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  • Background: Testosterone is a hormone that has been linked to aggression levels, it is found in higher levels in males than females.
  • Aim: Testosterone and its relationship with crime and prison behaviour
  • Participants: 692 male prison inmates.
  • Methodology: 
  • Procedure: Testosterone levels analysed from saliva sample and behaviour coded from prison records.
  • Results: Inmates with higher testosterone levels were found to have more violations of prison rules, for example overt confrontation. Higher levels were also found in those committing personal rather than property crimes. 
  • Conclusion: Differences in testosterone shown in the amount and pattern of misbehaviour. Males are more likely to be involved in crime than females. 
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Top-Down Typology

Canter et al.

  • Background: Begins with the big picture and then fills in the detail. Hazelwood and Douglas categorised organised (ordered life, high IQ, pre-determined and planned) and disorganised (passionate, unemplyed, often leaving evidence) crime
  • Aim: To test the reliability of organised and disorganised typologies. 
  • Participants: 100 American serial killer cases.
  • Methodology: Quasi experiment
  • Procedure: 3rd crime of each offender analysed by the crime classification manual (Douglas)
  • Results: Twice as many disorganised crimes than organised. 2 co-occurring behaviours in organised crimes: in 70% the body was concealed, in 75% sexual activity occurred. Sexual acts occurred in 2/3 of disorganised crimes. 
  • Conclusion: All had organised elements as they were not caught until after their third murder. Personality types should be considered and not overlooked. 
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Bottom-Up Approach

Canter and Heritage

  • Background: Looks for consistencies in behaviour. No initial assumptions are made. 
  • Aim: To identify a behaviour pattern from similarities between offences
  • Participants: 66 sexual offences, 27 offenders. Various police forces. 
  • Methodology: Quasi experiment
  • Procedure: Smallest space content analysis used. 
  • Results: 5 central variables were found suggesting a pattern of behaviour where the attack is impersonal:
          • Vaginal intercourse
          • No reaction to the victim
          • Impersonal language
          • Surprise attack
          • Victim's clothing disturbed
  • Conclusion: This is known as the 5 factor theory - it contributes to all sexual offences but there are different patterns in different offenders. It therefore helps to identify where the same individual is at work.
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Case Study of John Duffy


  • Background: Between 1975 and 1986, 23 women were *****, aged 15-32, at railways. John Duffy later confessed to having an accomplice: David Mulcahy.
  • Aim: To systematically document crimes and crime scene details to infer possible behavioural characteristics of an offender using psychological principles and scientific method
  • Participants: None
  • Methodology: Case study 
  • Procedure: Profile created: loner with 1 or 2 close male friends, small in structure, mid 20's, semi skilled job with knowledge if the railway, married without children, arrested for unrelated crime after 1983, lives in North West London. 
  • Results: John Duffy: 2 male friends, 5ft 4, lived in Kilburn, 28 on arrest, trained carpenter with British Rail, married but infertile, arrested for assualting wife.
  • Conclusion: Profile fit very well
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Detecting Lies

Mann et al 

  • Background: Police forces are trained to look at body language and detect lies
  • Aim: To test police officers' ability to distinguish truths from lies during interviews with suspects
  • Partcipants: 99 Kent officers, 24 male, 75 male, mean age of 34.3
  • Methodology: Field experiment
  • Procedure: 54 video clips of 14 real suspects in interviews. Head and torso. Clip backed up with evidence to confirm truth or lie. Questionnaire given to participant asking their experience in this field and what cues they used to make their decision.
  • Results: All performed better than chance. Accurate on 66.2% of lies and 63.6% of truths. Most used cues include gaze, movements, contradictions and fidgeting.
  • Conclusions: Police officers are good at detecting lies, a control group is needed to check against the public. 
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Interrogation Techniques


  • Background: Interrogation are used after interviews in order to obtain a confession. They're accusatory and used in torture. 
  • Aim: Develop approach to interrogation and justify the use of the Reid 'nine steps'
  • Partcipants: None
  • Methodology: 
  • Procedure: Justifying the Reid nine steps of interrogation
  • The Nine Steps:
    • 1. Direct confrontation
    • 2. Chance to shift the blame
    • 3. Never allow the suspect to deny they are guilty
    • 4. Ignore excuses
    • 5. Reinforce sincerity
    • 6. If suspect cries infer guilt
    • 7. Pose 'alternative question'  (two choices both inferring guilt)
    • 8. Get admission in front of witnesses
    • 9. Document admission
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False Confessions

Gudjohnsson et al

  • Background: Kassin and Wrightsman outlined three types: Voluntary (no external pressure), Coerced Compliant (forceful questionning) and Coerced Internalised (temporarily persuaded)
  • Aim: To document the case of a false confession in a 17 year old youth who was stressed and susceptible to interrogative pressure
  • Partcipants: 17 year old youth accused of the murder of two elderly women found battered and sexually assaulted in their own homes with their savings missing.
  • Methodology: Case study.
  • Procedure: Study in 1990 of 1987 case. Youth interrogated constantly, accused of lying and being sexually impotent. FC came after 14 hours but was retracted the next day. He then confessed again after being accused of impotence. Another individual pleaded guilty to the murders a year later. 
  • Results: No mental illness, the individual scored 10 on the Gudjohnsson susceptibility scale (very high)
  • Conclusions: Clear case of 'coerced compliant false confession'
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Recognising Faces


  • Background: Sinha found 8 important factors established by the meta-analysis of facial recognition research, two of these are that faces are processed holistically and the eyebrows and hairline are the most important.
  • Aim: Comparing the recognisability of internal vs external features of a facial composite
  • Partcipants: (1) 15 male, 15 female, staff and students at Stirling university. (2) 21 male, 27 female undergraduates.
  • Methodology: Both lab experiments
  • Procedure: (1) Photos of 10 celebs. 40 E-fit, Pro-fit, Sketch and Evo-fit composites. Composites must be placed in front of the celebs face. (2) 3 conditions: complete, internal and external features. Match composite to the photo-array. Easy condition (all composites are different) or hard (all are similar).
  • Results: (1) In the complete and external conditions, 35% were correct, in the internal condition 19.5% were correct. (2) External - 42% correct, internal - 24% correct. These results were consistent between botht the easy and the hard difficulties.
  • Conclusions: Internal features don't work well and should be avoided in the reconstruction of faces.
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Factors Influencing Identification


  • Background: Weapon focus is the concentration of a witness' attention on the criminal's weapon
  • Aim: Supporting the weapon focus effect theory
  • Participants: 36 volunteer students aged 18 - 31from the University of Washington.
  • Methodology: Lab experiment
  • Procedure: 1835mm slides, one showing a man queuing for a taco and paying, in the other he pulls out a gun. 20 multiple choice questions, 12 mug shots and ratings of confidence of correct identification on a scale of 1 - 6 are given.
  • Results: The control group were found to be correct 38.9% of the time, the weapon condition only 11.1%. No difference in confidence levels were found.
  • Conclusions: Supports the weapon focus effect
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Cognitive Interview


  • Background: Cognitive interviewing is a set of instructions the interviewer gives witnesses: interview similarity, focused retrieval, extensive retrieval, witness-compatible questionning)
  • Aim: Testing the cognitive interview techniques
  • Participants: 16 detectives from the robbery division in Florida, 8 trained in cognitive interviewing.
  • Methodology: Lab experiment
  • Procedure: Training consisted of 4 60 minute sessions and a post training interview which was blindly analysed. 
  • Results: CI trained detectives elicited 63% more information than the untrained detectives, there was no difference in the accuracy of the information.
  • Conclusion: More information obtained from witnesses with no loss of accuracy. Cognitive interviewing is now used by police in the UK.
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Witness Confidence

Penrod and Cutler

  • Background: Despite judges' instructions, one of the most convincing features of a witness is their confidence in their testimony 
  • Aim: Factors jurors consider with eye witness identification
  • Participants: Ungergraduates as jurors
  • Methodology: Lab experiment, independent measures
  • Procedure: Videotaped robbery, 80 or 100% confidence in her identification
  • Results: 100% confidence led to a 67% guilty verdict, 80% confidence led to 60% guilty verdict. Further studies show no correlation between confidence and accuracy.
  • Conclusion: Confidence is a poor predictor of accuracy but is trusted by jurors. 
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Attractiveness of the Defendant


  • Background: The 'halo effect' (Asch): a halo of pleasant characteristics are imagined when one favourable characteristic is perceived.
  • Aim: Is an attractive defendant less likely to be found guilty. Does an attractive victim make the defendant more likely to be found guilty. To investigate gender differences. 
  • Participants: 71 males, 74 females from East Carolina University. Given an extra psychology course credit.
  • Methodology: Lab experiment, independent measures.
  • Procedure: A sexual harrassment mock trial used. The vixtim and the defendant were categorised as attractive or unattractive on a scale of 1 - 9. The question was asked: "do you think Mr R is guilty of sexual harrassment?"
  • Results: Attractive defendants were found guilty 56% of the time, whereas unattractive defendants, 76% of the time. With an attractive victim the defendant was found guilty 77% of the time, whereas an unattractive victim only 55% of the time. 
  • Conclusions: Appearance has a powerful effect on guilty verdicts, defendants are encouraged to dress nicely for their court hearing.
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Effects of Shields and Videotape on Children Givin


  • Background: Often in cases of sexual abuse and kidnapping, the children are the only witnesses to the crime and therefore must testify. Giving evidence can be traumatic to children, and so screen and videos are used as protective measures.
  • Aim: Does the use of shields and videotapes on children giving evidence effect the juror's reaction to the testimony and the verdict they reach?
  • Participants: 150 male and 150 female psychology students, 100 per condition.
  • Methodology: Lab experiment, replica mock trial, independent measures. 
  • Procedure: Three versions filmed with actors: open court, behind a screen, using a video link. Accused was the child's father, it was a single touch in the bath. The jury were told not to infer guilt from the use of protective shields.
  • Results: No difference found between the conditions. Females found him guilty 58.6% of the time, males 38.6% of the time. No difference in the credibility ratings across the three conditions. 
  • Conclusions: The defendant is not more at risk if protective devices are used. 
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Order Testimony

Pennington and Hastie

  • Background: Story order is the presentation of witnesses in chronological order of the event. Witness order is strategically calling your witnesses so that the most important ones are firat or last so that they are most memorable. This is called the primacy-recency effect.
  • Aim: Are story order summaries causes of guilty verdicts, and how does it affect jurors' confidence,
  • Participants: 130 students from Northwestern and Chicago Universities, paid volunteers. 
  • Methodology: Lab experiment, independent measures.
  • Procedure: 4 conditions: Defence Story + Prosecution Story, Defence Story + Prosecution Witness, Defence Witness + Prosecution Witness, Defence Witness + Prosecution Story. 39 items used, the jurors had to decide whether the defendant was guilty or not guilty and rate their confidence on a 5 point scale.
  • Results: Ps + Dw = 78% guilty, Pw + Ds = 31% guilty. Confidence is increased in the verdict through the use of story order in the winning team.
  • Conclusions: The persuasive effect of presenting witnesses in story order is great.
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Expert Witness Persuasion


  • Background: Expert psychologist are often called upon to give their expert opinion as it may aid the jurors in reaching their verdict. Sometimes these experts can cast doubt upon an Eye Witness Testimony.
  • Aim: Does psychological evidence from expert witnesses, casting doubt upon an EWT, affect a juror's decision making?
  • Participants: 538 undergraduates given an extra psychology course credit. 
  • Methodology: Lab experiment, videod mock trail, independent measures. 
  • Procedure: Independent variables: witness identifying conditions (poor or good), witness confidence (80 or 100%), form of testimony (qualitative or quantitative based), expert opinion (on a scale of 0-25). The jurors were given a questionnaire asking their verdict, testing their memory and rating their confidence levels.
  • Results: More guilty verdicts were reached with good WIC, stronger expert opinions and with the 100% confidence.
  • Conclusions: Expert testimony improves juror's knowledge and therefore may help prevent miscarriages of justice. 
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Inadmissible Evidence


  • Background: The relevance of evidence must outweigh its potential for prejudice. 
  • Aim: Effect of prior convictions, role of judge's instructions followed by legal explanation, to examine credibility of witness affecting jurors' ability to ignore inadmissible evidence. 
  • Participants: 236 Bali State University psychology students randomly assigned to conditions. 
  • Methodology: Lab experiment, independent measures, mock trial.
  • Procedure: Mock trial of a fictional theft. Critical evidence introduced 'by mistake' by the witness, objected by the attorney, allowed or overruled by the judge and then followed by a legal explanation or not. The jurors had to listen to the mock trial, decide their verdict, the probable guilt of the defendant and the extent to which knowledge of the prior conviction affected their judgement. 
  • Results: With no legal explanation the inadmissible evidence was ignored, however with the legal explanation it could not be ignored. 
  • Conclusions: Calling attention to inadmissible evidence makes the jurors pay more attention to it and it therefore has a back-fire effect. 
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Decision Making


  • Background: How do the jury reach their verdict? Can stages in the process be defined?
  • Aim: Looked at decision making in unanimous, majority and divided verdicts.
  • Participants: --
  • Methodology: --
  • Procedure: --
  • Results: Three staged of decision making found:
    • Orientation period: open discussion, agenda set and opinions arise
    • Open confrontation: fierce debate, pressure on minority to conform, support for group decision established, focus on details.
    • Reconciliation: smoothing over of conflicts, tension released through humour, consensus reached. 
  • Conclusions: Social psychological research into group dynamics can be applied to this area.
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Majority Influence


  • Background: Individuals conform as they feel the need to both be right and belong to a group
  • Aim: Investigating the effects of a majority on conformity in an unambiguous task
  • Participants: 123 American male graduates, one participant and the others confederates.
  • Methodology: Lab experiment
  • Procedure: The confederates gave the same incorrect answer on 12/18 trials of the line perception task.
  • Results: 32% conformity rate, none conformed to all trials. 25% never conformed but 75% conformed at least once. Fidgeting and nervous laughter were common responses. With no confederates mistakes were made on only 1% of the trials.
  • Conclusions: The participants conformed due to distortions of perception, judgement and action It shows the impact of majority as well as the presence of free-will and resistance. 
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Minority Influence


  • Background: People reject the established norm of the majority and move to the minority. This often happens after a period of time for example the Nazis and Suffragettes.
  • Aim: Whether a consistent minority could influence the majority to give an incorrect answer on a colour perception task.
  • Participants: 172 females, no colour blindness
  • Methodology: Lab experiment, independent measures
  • Procedure: The 36 slides shown were all blue with varying brightness levels, 2/6 in the task were confederates and there was also a control group with no confederates. In the consistent condition, the confederates call green on all of the slides, in the inconsistent condition they call green on 24/36 slides. 
  • Results: In the consistent condition, participants called green 8.4% of the time, whereas in the inconsistent condition only 1.3%. In the consistent group 32% of participants called green at least once. In the control group green was called 0.25% of the time. 
  • Conclusions: The minority causes the majority to re-examine their views, consistency is the most important factor.
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