Making A Case - Interviewing Witnesses

Question 0

What was the aim of Bruce’s study?

Answer 0

To investigate the relative recognisability of internal and external features of a facial composite.

Question 1

What was the study on recognising faces?

Answer 1

Bruce, the importance of external and internal features in facial recognition.

Question 2

What was the method of Bruce’s study?

Answer 2

Three laboratory experiments

Question 3

Who were the participants in Bruce’s study?

Answer 3

Experiment 1: 30 staff and students from Stirling university paid £2 to sort the composites, 15 males & 15 females
Experiment 2: 48 undergraduates at Stirling university, 21 males, 27 females all volunteers
Experiment 3: ???

Question 4

What was the procedure of Bruce’s study?

Answer 4

Ex 1: target photos of 10 celebrities and 40 composites produced by E-FIT, PRO-fit, Sketch and EvoFIT. Clean shaven and glasses avoided. Three sets of composites used, a ‘complete’ set, a set containing internal features and a set containing external features. Participants tested on one of the three conditions, taking as long as they needed.
Ex 2: a photo line up with distractor faces/foils which were easy (all very different) or hard (all very similar) to identify. The composites were presented one at a time and the participant had to pick out the celebrity face from the array that matched the composite. The composites were either of internal or external features.
Ex 3: Familiar or unfamiliar target faces were presented to ‘witnesses’ for 30 seconds before they made a ProFIT composite. These were edited so they only showed internal or external features and were presented as before with whole faces to be matched and named.

Question 5

What were the results of Bruce’s study?

Answer 5

Ex1: whole composites bs those of external features were sorted similarly at approx 35% correct. Internal features were only 20% correct.
Ex2: composites of external features were identified more easily (at 42%) than internal features (24%) and this was consistent across array type (easy or hard)
Ex3: sorting was accurate at approx 60% and did not matter if face was familiar or unfamiliar. External features more accurate than internal (55% to 30%). The naming task was 22% accurate whether familiar or unfamiliar.

Question 6

What were the conclusions of Bruce’s study?

Answer 6

In ex1 and ex2 participants performed just above chance with internal features and ex3 showed familiarity with the target improves sorters success to 57%. In all cases participants performed equally well with external features or while faces. This could indicate that there is something about the internal features of a face that does not work well when trying to recreate a reconstruction, this effect even applies to familiar faces.

Question 7

What was the study on factors influencing identification?

Answer 7

Loftus, facts about ‘weapon focus’

Question 8

What is the ‘weapon focus’ effect?

Answer 8

The concentration of a crime witnesses’ attention on a weapon and the resultant difficulty in remembering other details of the scene.

Question 9

What was the aim of Loftus’ study?

Answer 9

To provide support for the ‘weapon focus’ effect when witnessing a crime.

Question 10

What was the method of Loftus’ study?

Answer 10

A laboratory experiment

Question 11

Who were the participants in Loftus’ study?

Answer 11

36 students at the university of Washington. Half recruited through an advertisement and were paid $3.50 for their participation. The remainder participated in exchange for extra credit in their psychology classes.

Question 12

What was the procedure for Loftus’ study?

Answer 12

Two sets of 35mm slides were shown. There were 18 slides in each series showing people queuing in a Taco Time restaurant. In the control group, person B hands the cashier a cheque. In the experimental condition person B pulls out a gun. All other slides were identical and shown for 1.5 seconds. The DV was measured through a 20-item multiple choice questionnaire. The participants were also given a line up of 12 head and shoulder photos in a random sequence and asked to rate how confident they were on a scale of 1 to 6 (1=guess, 6=very sure)

Question 13

What were the results of Loftus’ study?

Answer 13

Answers to the questionnaire showed no significant difference between the two conditions. In the control condition 40% chose the correct person B against 10% in the weapon condition. There was no difference in the confidence level of either group. Eye fixation was higher on the gun than the cheque.

Question 14

What was the study on the cognitive interview?

Answer 14

Fisher, field test of the cognitive interview.

Question 15

What are the four basic principles of the cognitive interview?

Answer 15

1. Interview similarity - interviewed in a similar environment to the original event
2. Focused retrieval - generate focused concentration, no interruption to the chain of thought and plenty of encouragement to try hard
3. Extensive retrieval - witness encouraged to make as many retrieval attempts as possible. Try another angle, even seemingly irrelevant details are requested.
4. Witness-compatible questioning - interviewers should be flexible and alter their approach to meet the needs of each witness

Question 16

What was the aim of Fisher’s study?

Answer 16

To test the cognitive interview in the field

Question 17

What was the method of Fisher’s study?

Answer 17

A field experiment with actual interviews of real witnesses by serving police detectives

Question 18

Who were the participants in Fisher’s study?

Answer 18

16 detectives from the robbery division of Dade county, Florida. All were experienced with a minimum of 5 years with the division.

Question 19

What was the procedure of Fisher’s study?

Answer 19

In the first phase detectives were asked to record a selection of their next interviews using their standard techniques. This took ; months and 88 interviews were recorded. The detectives were then divided into 2 groups and one group was trained in cognitive interview techniques. Training was over 4 60-minute sessions. 7 detectives competed the programme and over the next 7 months more interviews were recorded by the two groups. The post-training interviews were analysed by a team at the university of California, who were blind to the conditions (trained of untrained in CI)

Question 20

What were the results of Fisher’s study?

Answer 20

The 7 trained detectives gained 50% more information than before and 65% more information than the untrained detectives. In 24 cases with corroborating evidence (16 by pre-trained detectives and 8 by post-trained detectives) 95% of the statements were corroborated. Time taken to interview witnesses was not significantly different but CIs do take longer.