Recognising Faces - Bruce et al
Aim: To investigate whether people are more likely to recognise internal or external facial features on a person.
Participants: 30 staff and students from Stirling University.
Procedure: Participants were tested individually on one of the tree conditions (complete face, face with internal features or face with external features) They were asked to place each composite in front of the celebrity face.
Results: Whole composites and those of external features were sorted similarly at approximatively 35% accuracy. The composites of internal features showed only 20% accuracy.
Conclusion: Internal features of faces are not recognised well in re-constructive techniques, even when the face is familiar. External information of suspects is remembered more readily by witnesses.
Factors Influencing Identification - Loftus et al
Aim: To provide support for the 'weapon focus' effect when witnessing a crime.
Participants: 36 students at Washington University.
Procedure: Participants were put into two different conditions. Both were shown a set of slides which shows a queue at a restaurant counter. In condition A the second in line pulls out a gun. In condition B the second in line pulls out a cheque. The participants completed a 20 multiple choice questionnaire. The participants were also given a line up of 12 head-and-shoulder photos in a random sequence and asked to identify and rate their confidence on a scale of 1 – 6.
Findings: Answers from the questionnaire about the slides showed no significant difference between the two conditions. However there was higher correct identification in the cheque group but no difference in confidence. Eye fixation data lasted longer on the gun than the cheque.
Conclusion: Participants spent longer looking at the weapon, this will then affect their ability to pick out the suspect in a line up.
Cognitive Interview – Fisher
Aim: To test the cognitive interview in the field.
Participants: 16 serving detectives from Florida.
Procedure: In the first phase of the experiment, detectives were asked to record a selection of their next interviews using the standard techniques they normally used. This took 4 months and 88 interviews were recorded mostly related to theft. The detectives were then divided into two groups and one group was trained in CI. Training was after 4 60-minute sessions. Seven detectives completed the programme. Over the next 7 months further interviews were recorded by the 2 groups. The post-training interviews were analysed by a team at the university of California who were blind to the conditions.
Findings: After training, the 7 trained detectives elicited 47% more information than before and 63% more than the untrained detectives.
Conclusion: Strong support was obtained for the effectiveness of CI.
Detecting Lies - Mann et al
Aim: To test police officers' ability to distinguish truths and lies during police interviews with suspects.
Participants: 99 Kent police officers.
Procedure: They were asked to judge the truthfulness of people in real-life police interviews. They saw video clips of 14 suspects showing their head and torso. These clips were backed by other evidence which established whether the suspect was lying or telling the truth at any point. The 54 clips varied in length from 6 to 145 seconds. The police officers began by filling out a questionnaire about their experience in detecting lies. They watched the clips and after each one indicated whether they thought it was a lie or the truth and how confident they were in that decision. Finally they were asked to list the cues they used.
Findings: The most frequently mentioned cue to detect lying was gaze, followed by; movements, vagueness, contradictions in stories and fidgeting.
Conclusion: The findings were not significant at the 5% level of significance, however more experienced officers detected more lies and truths than less experienced officers and they do so based on cues rather than body language etc.
Interrogation techniques - Inbau
Inbau developed an approach to interrogation which relied on presenting a mass of damaging facts to persuade criminals that they had no choice but to confess.
The nine stages are:
- Direct confrontation – they are told they have committed the offence.
- Blame shift – offer sympathy and justifications to make it easier to admit guilt
- Prevent denial of guilt.
- Ignore any information from the suspect that represents an attempt to evade guilt.
- Reinforce sincerity - to keep the suspect on their side.
- Offer alternative suggestions when the suspect becomes quiet
- Alternative question – pose two different questions as to what the suspect can do, one more socially acceptable but both involving the suspect admitting guilt
- Witness – admission should always be in the presence of a witness.
- Confession – document their confession.
False Confessions – Kassin and Keitchel
Aim: To investigate the effect of suggestibility on false confessions.
Procedure: Participants were given a reaction time test on a computer but told not to touch the ALT key. In some cases, there was a witness who made the false claim of seeing the participants touch the key.
Findings: On average, 69% of the participants admitted touching the ALT Key after this false claim, 30% admitting they had seen someone else and 10% pictured themselves doing so.
Conclusion: Participants had internalised the claims (believed they had done it) even though they actually hadn't. This suggests that police are able to influence suspects into giving confessions through the power of suggestion.
Top Down Approach (USA) - Canter
Aim: To test the reliability of organised (plan their crimes, show self control etc) and disorganised (don't plan, leave more clues etc) typologies.
Procedure: Content analysis of 100 cases of serial killers in the USA. The third crime committed by each serial killer was analysed using The Crime Classification Manual.
Findings: Twice as many disorganised as organised crime-scenes were identified. In 70% of cases the body was concealed and in 75% sexual activity occurred and further analysis failed to reveal any significant difference between the two.
Conclusion: Instead of their being a distinction between the two types of serial murder, all of the crimes had to have an organised element to them as they hadn't been caught after three killings. Personality variables would be a better factor to research.
Bottom Up (UK) – Canter and Heritage
Aim: To identify a behaviour pattern from similarities between offences.
Procedure: A content analysis of 66 sexual offences from various police forces committed by 27 offenders was conducted to find 33 offence variables that were clearly linked to a potential behaviour characteristic.
Findings: Central behaviours included, vaginal intercourse, no reaction with the victim, impersonal language, surprise attack and victims clothes were disturbed. Less central behaviours included, attempted intimacy with the victim, sexual behaviour, overt violence and aggression, impersonal interaction and criminal behaviour and intent.
Conclusion: These 5 factors have been shown to contribute to all sexual offences but in different patterns for different individuals which can lead to understanding how an offenders behaviour changes over time or whether two or more offences were committed by the same person. This has become known as the 5-factor theory.
Case Study - Canter
John Duffy was a serial ****** and killer who, in 2000, confessed to committing 25 offences between 1975 and 1986. His victims were always women, aged between 15 and 32 and targeted near railway stations in and around London
Canter got involved in the early 80's and based his profile on the locations of the crimes and the evidence of Duffy's behaviour. According to his profile Duffy was a marauder who committed his crimes near his home.
Preliminary profile: Canter suggested that the suspect would:
- Have possibly been arrested some time after 1983.
- Probably lived in that area at the time of arrest.
- Probably lives with a woman but no children.
- Mid to late twenties, light hair, 5 foot 9, right handed..
- His job probably doesn't bring him into contact with public..
- Knowledge of the railway where the attacks happened.
- Considerable sexual experience due to the variety of his sexual actions.
Duffy was caught out of 2000 suspects using this method.