Eyewitness testimony and cognitive interview

Eye witness testimony (EWT)

legal term that refers to the use of eye witnesses to give evidence in court

misleading information

• accuracy of EWT can be affected by misleading information

• Can take many forms such as leading questions and post event discussion

Explanations of post-event discussions for affecting EWT

memory contamination: memories become distorted because witnesses combine their memories with other peoples

Memory conformity: witnesses go along with other peoples memories, actual memory is unchanged

Memory contamination research

• Anna Lindh, Swedish minister for foreign affairs

• Stabbed in a department store

• Witnesses discussed with each other while together, one witness mentioned that the attacker had ben wearing a camouflage-patterned military jacket

• This information was incorrect

Memory conformity research

Grabber et al

• students participants in pairs

• All watched same video of crime, but watched it filmed from different points of view

• Partners were put together to discuss what they saw

• 71% of ppts mistakenly recalled aspects they did not watch from the video

• 0% of ppts in control recalled false aspects

Barlett’s theory

Reconstructive memory suggests in the absence of information, we fill in gaps to make sense of what happened, due to schemas

Research on leading questions aim

Loftus and Palmer

To investigate how post event information (leading questions) can influence the memory of an eyewitness

Research on leading questions conditions

• lab experiment

• Independent measure design

• 45 American university students

Research on leading questions procedure

1. All shown series of clips on car accidents

2. Leading question involved how fast the car went (hit/smashed/collided)

3. Verb in question had an impact on how fast people though the car was going

Suggests eye witness immediate recall can be affected by leading questions

strengths of this research

1. Lab experiment, high internal validity

2. Real world application

Limitations of this research

1. Ethnocentric

2. Only young people

3. Extraneous variables

4. Lab experiment, low external validity

Anxiety definition

Characterised by experiences of worry and tension

effects of anxiety

• heighten concentration

• Hyper fixation

• Fight or flight

• Memory problems

Negative impact of stress on EWT

In crime, high physiological arousal can cause attention to focus on certain details of events, missing other details

Stress impact on EWT research aim

Johnson and Scott

To investigate weapon-focus effect and impact on accuracy of recall

stress impact on EWT procedure

• Independent group design

• Participants were asked to sit in a room and herd discussion in a nearby room

Condition 1: man came out of the room with a pen and grease on his hands

Condition 2: man came out of the room carrying a knife object in blood

• participants asked to identify the man from 50 photographs

Stress impact on EWT research findings

• participants in no-weapon condition were accurate 49%

• Participants in weapon condition were accurate 33%

Positive impact of stress on EWT

Flight or fright response is triggered which may improve memory recall as we become more aware of details in the situation

positive impact of stress on EWT research 1

Yuille and Cuthall

• studied a real life shooting in Canda, where an owner killed a thief

• Of the 21 eyewitnesses, 13 took part in the study

• 4-5 months later they were asked to recall the event

• This was compared to original police report

• Results how little change in their recall, high level of accuracy

• Those who had highest levels of stress had highest levels of accuracy

impact of stress on EWT research

Deffenbacher

• reviewed 21 studies of effects of anxiety on EWT memory

• Found that 10 of the studies had results which showed higher anxiety to higher accuracy

• 11 studies showed the opposite

Yerkes-Dodson law

Memory recall improves as anxiety increases up to an optimal point then declines

Cognitive interview key points

1. Report everything: additional info can act as cues

2. Mental reinstatement of original context: mentally recreate the environment (smells), and emotional context (feelings)

3. Changing the order: help participant with cues, and prevents dishonesty

4. Changing the perspective

Enhanced cognitive interview

• fisher developed additional elements of cognitive interview

• Make witness feel comfortable

• Techniques to reduced anxiety

• Minimise distractions

• Ask open-ended questions

Limitations of cognitive interview

1. Changing order may be harder for people

2. People may find it hard to change the perspective, due to tunnel-vision of the crime

3. Time and money consuming to find police officer trained

4. Not all techniques appropriate for children

Evidence of cognitive interview

• trained detectives from Miami Police Department use cognitive interview

1. Police interviews with eyewitnesses and victims were videoed and total number of statements recorded

2. A second eyewitness asked to confirm whether statements were true

3. Cognitive interview produced 46% increase in recall, 90% accuracy

Evidence of cognitive interview 2 aim

Geiselmen et al

To investigate the effectiveness of cognitive interview

evidence of cognitive interview 2 method

1. Participants viewed film of violent crime

2. After 48 hours, were interviewed by policeman by either, cognitive interview, standard interview or hypnosis

3. Number of facts accurately and wrongly recorded

Evidence of cognitive interview 2 results

Number of correctly recalled facts

Cognitive interview: 41.2

Hypnosis: 38

Standard interview: 29.4

Research against CI

Milne shows that CI can get accurate information, but doesn’t increase information. Recalling from another perspective can get false information.