Making a Case

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Bruce et al., (2007) Facial Recognition

Based on the idea that familiar faces are more easy to recognise than those unfamiliar to us.

Three laboratory experiments.

30 gender balanced staff/students from Stirling Uni were asked to match up 40 composite images, made with E-FIT to 10 celebrity photos. Three sets were used containing either the whole face, just internal features or just external features. 

48 undergraduates from the same uni were shown a photo line up of celebrities then shown the composites one at at time. The participants had to pick the celebrity face that matched the composite they were shown. Again only internal or external features were used.

Results -

  • Experiment 1: People matched external features and whole faces correctly 35% of the time and only 19.5% of the time with internal features.
  • Experiment 2: Images of external features (42%) were identified more easily than internal features (24%) and this was consistent across difficult and easy types.
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Bruce et al., (2007) Cont.

Evaluation -

  • Small samples making it unreliable
  • Atypical sample making it ungeneralisable
  • High control of variables 

Debates -

  • Psychology as a science? - replicable, falsifiable, objective
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Loftus et al., (1987) Weapon Focus

Weapons focus is based on the idea that witness' focus is on a weapon meaning a reduced ability to remember other details from a crime

36 students at the University of Washington, aged 18-31. Recruited through advertisment and either given $3.50 or extra credit in psychology class. Control group were shown slides of a queue of people in a Taco Bell restaurant. Person B hands the cashier a cheque. Experimental group shown same slides as the control but person B pulls a gun instead. Participants were asked to fill out a multichoice, 20 item, questionnaire and to pick person B out 12 head to shoulder photos and rate how confident they were in their choice on a scale of 1-6.


  • Control participants chose correctly 38.9% of the time whereas weapon condition chose correctly 11.1% of the time.
  • There was no difference in confidence of the participants across the conditions
  • Eye fixation data showed an average of 3.72 on the gun and 2.44 on the cheque.
  • Participants spent longer looking at the weapon therefore had more difficulty identifiying the suspect.The influence may be greater in reality when a witness would be more aroused.
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Loftus et al., (1987) Cont.

Conclusion - Provides support for the idea of weapons focus

Evaluation - 

  • Second study had a more reliable sample size 
  • Good control of variables 
  • Lacks ecological validity 
  • Ethically sound - lack of stress (shown on slides) 

Debates - 

  • Reductionist - individual differences is not considered
  • Psychology as a Science? - Replicable, falsifiable, objective

Usefulness - 

  • Implications for the usefulness of eyewitness testimony
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Fisher et al., (1989) Cognitive Interview

To test the cognitive interview technique (CIT) in a field study using 16 detectives in the Robbery Division of the Florida Police Department.

All detectives recorded a selection of their normal interviews. 7 detectives were then trained in CIT and all detectives recorded interviews after this. These were then analysed by blind researcher at the University of California.

Results -

  • After training in CIT the trained detectives elicited 47% more information than before
  • They also found 63% more information than the untrained detectives.
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Fisher et al., (1989) Cont.

Evaluation - 

  • Small sample - unreliable
  • Only based on one type of crime (robbery) 
  • Geographically specific 

Debates - 

  • Nature/Nurture - Techniques can be learnt

Usefulness - 

  • Shows that CIT is effective in improving information retrieval
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Mann et al., (2004) Ability to Detect Lies

A review by Vrij (2000) showed that there were 94% of police officers that did no better than chance factors in detecting deception

99 Police Officers from Kent were used to test police officers ability to detect lies during police interviews

Participants saw video clips of 14 suspects showing their head and torso so expression and movement could be seen. The police officers then filled out a questionnaire about their experinece in detecting lies. They watched the clips and indicated whether each one was a truth or lie, and in addition how confident they were. Finally they were asked to list the cues used to detect the liars.

Results -

  • Difference between mean lie and mean truth accuracy is not significant but boths levels of accuracy are greater than chance.
  • Experience in interviewing was correlated with truth accuracy.
  • The most frequently mentioned cue to detect lying was gaze, second was movemenet; vagueness, contradictions in stories and fidgeting were also mentioned.
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Mann et al., (2004) Cont.

Discussion -

  • Higher accuracy than in previous studies 
  • Police officers who were good at detecting lies relied more on verbal cues (contradictions) than non-verbal cues (fidgiting)

Evaluation - 

  • Lack of control group to look at 'normal' peoples ability to detect lies

Issues - 

  • Ethics - if a control group had been used 'normal' participants would not have been able to be exposed to sensitive material, leading to reliance on actors, which causes Ecological Validity issues

Debates - 

  • Nature/Nurture - Experience effects the police officers ability to detect lies
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Inbau et al., (1989) 'Nine-steps' to Interrogation

Reid 'Nine Steps of Interrogation' in brief

  • Direct confrontation: the suspect is told directly that they are thought to have committed the offence.
  • The suspect is offered the chance to shift the blame from themself by being offered some suggestions or justifications for what happened.
  • The suspect should never be allowed to deny guilt. Interrupt any denial.
  • Ignore any reasons why they could not have committed a crime. Eventually they will give up.
  • Reinforce sincerity to ensure the suspect is receptive by staying close, using first names and keeping good eye contact.
  • The suspect will eventually becoming quieter and listen. If they cry, infer guilt.
  • Pose the 'alternative question': two choices, one more socially acceptable than the other - whichever they choose they will be admitting their guilt.
  • Get the suspect to admit guilt in front of witnesses.
  • Document their admissions and get them to sign a confession so they cannot retract it
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Inbau et al., (1989) Cont.

Evaluation - 

  • Can result in false confessions from those who highly suggestible.
  • Labelling someone as guilty can mean behaviour is intepreted as guilty even if its not

Links - 

  • 'Sane in Insane Places' (Rosenhan 1973)

Debates -

  • Social determinsm - Situational explanation of behaviour
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Gudjohnnson et al., (1990) False Confession

To document a case of the false confession of a 17 year old, who was at the time distressed and susceptible to interrogative pressure afte being accused of the murder of two elderly women in 1987

Data was collected through 5 interviews, the first interview conducted lasted nearly 14 hours.

Results -

  • To start with he denied being near the scene but he agreed after being repeatedly accused of lying. There were many leading questions and he was accused of being sexually impotent which he found distressing.
  • In the second interview he retracted his statement only to confess again under pressure. There were three further interviews.
  • In prison he was examined by psychiatrists who found no evidence of mental illness.
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Gudjohnsson et al., (1990) Cont.

Evaluation -

  •  Confrontational interrogation is more likely to lead to false confession.

Debates - 

  • Social Determinism - Situational explanations for behaviour

Usefuless - 

  • Identifying that people other than those previously considered vunerable to false confessions are also at risk of it is essential in order to ensure interview techniques produce valid confessions.
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Canter et al., (2004) Organised/Disorganised Crime

To test the reliability of organised/disorganised typologies as a way to classify serial killers

A content analysis was applied to 100 cases of US serial killers.

Results -

  • Twice as many organised as disorganised crime scene actions were identified suggesting that organised offenders are more common or, alternatively, easier to identify.
  • Only two crime scene actions co-occurred in the organised typologies in a level significantly above chance: the body was concealed and sexual activity occurred.
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Canter et al., (2004) Cont.

Conclusion - 

  • Instead of there being a distinction between two types of serial murder, all such crimes will have an organised element to them, as we might expect from the fact that the killers were not caught after three killings.
  • He suggests a better way is to look at the individual personality differences between the offenders.

Evaluation - 

  • Database eliminates researcher bias
  • Statistical analysis and cross-checking makes it reliable 

Debates - 

  • Psychology as a Science? - Moving the way offender profiling is conducted towards scientific procedures making it more falsifiable, reliable and objective.
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Canter (1996) Bottom-Up Approach

Identifying a pattern between offender characteristics and offence behaviour using a content analysis of 27 sex offenders and their 66 sexual offences using records from various UK police forces

Results -

  • The following variables were found to be central to the 66 cases of sexual assault: 
    • vaginal intercourse, 
    • no reaction to the victim, 
    • impersonal language, 
    • surprise attack, 
    • victim's clothing disturbed. 
  • This suggests a pattern of behaviour where the attack is impersonal and sudden and the victim's response is irrelevant to the offender. 
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Canter (1996) Cont.

Evaluation - 

  • Statistical approach allows greater confidence in results 
  • Small sample, and restricted crime type

Debates - 

  • Less reductionist as a large number of variables/behaviours investigated
  • Psychology as a Science? - Moving the way offender profiling is conducted towards scientific procedures making it more falsifiable, reliable and objective.
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Canter (1995) John Duffy, 'Railway Rapist'

Canter became involved in the case of John Duffy in 1985 when police asked if he could help them catch the man 'before he kills again'

Canter used bottom up approach to build up a profile of the attackers personality based on evidence left at the scene and he built up a geographic profile of the offender by laying transparent acetate sheets with the crime scenes marked on top of a map of the area surrounding London. The profile included traits such as married, semi-skilled job, aged 20-30, short, unattractive, had had a previous offence, lived in Kilburn/Cricklewood area, and had a need to dominate women.

Duffy matched all these criteria, aged 28, 5"4, having achne scars from when he was younger, had previously been convicted for attacking his wife, and lived in Kilburn.

Previous to Canters involvement Duffy was the 1505th of 2000 suspects. Yet after matching the profile Duffy was the only one to match all critera.

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Canter (1995) Cont.

Debates - 

  • Individual explanations for behaviour
  • Identifying characteristics of the offender allows police to narrow down their list of suspects and direct their resources
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