Interviewing Witnesses - Bruce
Aim: To investigate the recognisability of internal (nose, eyes, brows, mouth) and external (head shape, ears, hair) in facial recognition.
Method: Lab experiment using independent measures design.
Sample: 30 staff and students of Stirling University in Scotland.
Procedure: Participants were given 10 pictures of celebrities and asked to match the correct composite image to the celebrity from 40 composites given.
Group 1 was given complete composites.
Group 2 was given only external feature composites.
Group 3 was given only internal feature composites.
Results: 42% of complete composites and external features were correctly matched to the celeb photo, compared to only 19.5% of internal features.
Conclusion: External features are more important for facial recognition than internal features and faces are processed holistically
Interviewing Witnesses - Loftus
Aim: To provide evidence for the weapon focus effect when witnessing a crime.
Method: Lab experiment
Sample: 36 students from the University of Washington. Half were recruited via advertisement and paid $3.50, the other half were psychology students given extra credits.
Procedure: Participants were divided into 2 groups, the experimental group and the control group.
They both were shown 18 slides of a queue in a taco shop, the only difference was one slide.
The IV was if whether the second man in the queue pulled out a gun (experimental group), or if he pulled out a cheque (control group)
Participants were then given a line up of photo's to identify the person and a questionnaire. Researchers also used technology to measure eye fixation on the gun or cheque.
Results: 39.8% of people correctly identified the suspect in the cheque condition, compared to 11.1% for the gun. There was also a significantly longer eye fixation time on the gun compared to the cheque. Conclusion: Participants spent longer looking at the gun and therefore had more difficulty in identifying the suspect.
Interviewing Witnesses - Fisher
Aim: To test the cognitive interview (CI) in the field
Participants: 16 detectives from Florida. All were experienced with a minimum of 5 years in the division.
Method: Field Experiment.
Procedure: All participants were asked to record a selection of their interviews using the standard interview technique. Then the group was split into two groups. The first group continued using the standard interview technique, but the other's were given four, one hour sessions training them in the CI. They then implemented these techniques in their interviews.
Findings: Police officers who were trained in the CI elicited 63% more information than the standard interview group.
Conclusion: Cognitive Interview techniques seem to gain more information without losing accuracy.
Interviewing Suspects - Mann
Aim: To test police officers ability to distinguish truth and lies during interviews with suspects.
Method: Field experiment
Sample: 99 Police officers from Kent.
Procedure: Police officers were shown 54 cvideo clips of 14 suspects of real life police interviews. The clips were of head to torso range and they were asked:
- Truth or lie?
- What cues helped you reach your decision?
Results: It was found that police officers could accurately detect lies 66% of the time, which is better than chance. The most frequently mentioned cues were gaze, fidgeting and contradictions in the story.
Conclusion: Police officers are better at detecting lies than chance and the best lie detectors relied on story cues as opposed to body cues.
Interviewing Suspects - Inbau
Step 1 - Direct Confrontation. Lead the suspect to understand that the evidence has led the police to the individual as a suspect. Offer the person an early opportunity to explain why the offence took place.
Step 2 - Try to shift the blame away from the suspect to some other person or set of circumstances that prompted the suspect to commit the crime. That is, develop themes containing reasons that will justify or excuse the crime. Themes may be developed or changed to find one to which the accused is most responsive.
Step 3 - Never allow the suspect to deny guilt. If you've let him talk and say the words ‘I didn't do it’, and the more often a person says ‘I didn't do it’, the more difficult it is to get a confession."
Step 4 - Ignore excuses. At this point, the accused will often give a reason why he or she did not or could not commit the crime. Try to use this to move towards the confession.
Step 5 - Reinforce sincerity to ensure that the suspect is receptive.
Step 6 - If suspect cries, infer guilt. The suspect will become quieter and listen. Move the theme discussion towards offering alternatives. If the suspect cries at this point, infer guilt.
Step 7 - Pose the “alternative question”, giving two choices for what happened; one more socially acceptable than the other. The suspect is expected to choose the easier option but whichever alternative the suspect chooses, guilt is admitted.
Step 8 - Admit guilt. Lead the suspect to repeat the admission of guilt in front of witnesses.
Step 9 -Confession. Document the suspect's admission and have him or her sign as a confession.
Interviewing Suspects - Gudjohnsson
Aim: To document a case of false confession of a youth who was at the time distressed and susceptible to interrogative pressure.
Participant: 17 year old 'F.C' who was of average intelligence, suffered from no mental illness and his personality was within normal parameters.
Procedure: This was a case study of F.C, a 17 year old youth who was accused of two murders. In 1987 two elderly women were found battered to death in their home, their savings were missing and they had been sexually assaulted. F.C was arrested because of inconsistencies in account of his movements during an earlier routine inquiry and because he was spending more money than usual. There was no forensic evidence, it was all purely circumstantial After his arrest, he was denied access to a solicitor and was interviewed at length by police, leading to a confession. The next day he repeated his confession in front of his solicitor and wrote a statement incriminating himself. A year later he was cleared after another man was found to have carried out the attacks.During the interview, he was repeatedly accused of lying, the questioning was leading and accusatory and often accused of being sexually impotent. He was interrogated for 14 hours throughout the night. In prison, he was assessed on several psychological tests and passed them all, apart from the Gudjohnsson suggestibility scale where he scored very highly.
Conclusion: This is a clear case of coerced false confession where suspects knowingly make a false confession due to the need to escape the stress of interview. He gave into the intolerable pressure from the interrogation. It also shows that individuals who are extremely suggestible will succumb to the pressure of interrogation.
Creating a Profile - Canter
Case Study- Offender profiling
The first well known case in Britain which Canter used his profiling techniques was the case of the 'Railway Rapist', John Duffy. This case involved 24 sexual assaults in North London and three murders. All the crimes showed signs of having been committed by the same individual or individuals.
The first attacks were rapes, which were initially thought to be the work of two offenders together. Although John Duffy was found to have committed the crimes, he was helped by another man. Drawing on his study of the details of the crimes and early geographical profiling techniques, Canter was able to analyse the details and drew up a profile that was to prove remarkably accurate. Duffy was also already on a police database as he had been interviewed in connection with an attack on his ex-wife. He was also one of the nearly 2000 suspects linked to the crime by blood group. However, it was Canters geographical profiling approach that was instrumental to his arrest. Duffy was the only suspect who lived in the Kilburn area of London predicted as the home location by Canter and exhibited other characteristics predicted by Canter.
Main points of Canters Profile:Lived in area near to the area of the first crime, Semi-skilled job with weekend work but relatively isolated work, Knowledge of railways, Previous criminal record, Keep souvenirs of crime.
Actual characteristics of Duffy:Lived in Kilburn, Travelling Carpenter, Worked for British rail, Raped wife at knife point, Tied up wife before sex, Had 33 door keys from victims.
Creating a Profile - Canter and Heritage
Aim: To identify behaviour patterns from similarities between offences.
Method: A content analysis was carried out on the 66 sexual assault cases from various police forces. The data was subjected to Canter's smallest space analysis (a computer programme which uses analysis to find correlating patterns of behaviour)
Results: Five variables were fond common to the 66 cases:
No reaction to the victim
Victim's clothing disturbed.
These are the most common features of ****, and as such they are not very useful for distinguishing between different types of **** crime scene.
Conclusion: These 5 variables have now been shown to contribute to all sexual offences but in different patterns for different individuals and therefore analysis of these factors can enable police to decide if an offence has been committed by the same individual.
Creating a Profile - Canter et al
Organised - Average to high intelligence, Socially competent, Plans offences, Uses restraints on victims, Targeted stranger as a victim.
Disorganised: Below average intelligence, Socially incompetent, Unskilled or unemployed, Minimal use of restraints/ leaves body on display, Victim is know n to the offender and is often spontaneous.
Aim: to test the reliability of organised/disorganised typologies.
Methods: A content analysis using the psychometric method of multi-dimensional scaling
Procedure: 100 cases were assessed to find out if the features hypothesised to belong to each typology would be consistently and distinctively different. All the cases were from the U.S.A. and it was the third crime committed by each serial killer that was analysed for the research. The Crime Classification Manual (Douglas et al. 1992) was used to classify the crimes as organised or disorganised as far as was possible based on replies to interviews.
Results: Twice as many disorganised as organised crime scene actions were identified suggesting that disorganised offenders are more common or, alternatively, easier to identify. Only two crime scene behaviours significantly co-occurred in the organised typologies: the body was conealed in 70% of cases and sexual activity occurred in 75% of cases. Most of the other crime scene behaviours co-occur regularly in less than half the crimes in which they happen. Further statistical analysis (Smallest Space Analysis) failed to separate the variables for organised and disorganised crime clearly.Instead the organised variables appeared central in the scattered plot with disorganised variables spread widely around them.
Conclusion: There is no distinction between two types of serial murder, all such crimes will have an organised element to them.