Eye witness testimony

Eye witness testimony

1. Evidence supplied by people who witness an event firsthand relying only on their memory.

2. Age of the witness

   • Children's reliability (Pozzulo & Lindsey 1998) - Conducted meta analysis which showed P's a slide sequence of a mock crime and they must pick a culprit. Under 5's were least likely to identify, children over 5 were as likely to be correct as adults when culprit was present. Children up to 13 were more likely to choose someone even if the culprit wasn't present (children are more likely to respond to social demands)
   • Younger children of 3-4 years are more suggestible (Bronfenbrenner 1988) - more likely to agree with misleading information and let it influence their EWT
   • Cognitive incompetence (Bruck & Melnyk 2004) - children lack necessary language skills to give an accurate account
   • Older eyewitnesses are more influenced by misleading suggestions (Mueller-Johnson and Ceci 2004) - older adults and younger adults underwent a massage. Several weeks later the P's were given misleading information (did you enjoy hand massage) and this distorted the memory of older adults more than the younger ones
   • Own age bias - P's from young, middle aged and older age groups were shown 24 photos and had to rate them on attractiveness. After filler activity they had to recall who they recognised. Recognition rates were higher for the young and middle aged P's, older aged p's were more accurate at identifying photos from their own age group.
   • To increase accuracy of EWT by older eyewitnesses they could reduce misleading questions and interview them as soon as possible after there event.

3. Anxiety of the witness

   • Performance of EWT increases with stress up to an optimal point where it starts to decline
     • Clifford and scott (1978) found that people who saw a film of a violent attack remembered fewer of the 40 items of information about the event than a control group that saw a less stressful version
       • Yuille and Cutshall (1986) contradicts this - showed real life witnesses had remarkable accurate memories of a stressful event and two misleading questions had no effect on the recall accuracy
   • Deffenbacher reviewed 21 studies and found that the stress - performance relationship followed an inverted-U function proposed by the Yerkes Dodson Curve
   • Evaluation
     • Individual differences in anxiety - individuals may have a different starting point
   • emotional arousal can aid memory

4. Weapon focus

   • Eye witnesses concentration on a weapon to exclusion of other details of the crime.
   • Loftus et al. (1979) used a laboratory based experiment with independent groups design. Condition 1 - they over heard a friendly conversation and man came out holding a pen. Condition 2 - heard a heated discussion and man came out holding a knife. Then they had to identify the man, condition 1 - 49 were correct, condition 2 - 33. Heightened anxiety caused P's to focus on the weapon
   • Evaluation
     • Lab based experiment so had ecological validity
     • Raises ethical issue of deception and protection from harm
     • Knife is unusual so results may not have been due to anxiety but level of interest

5. Misleading information

   • Leading questions (Loftus and Palmer 1974) - Lab based experiment with an independant groups design. 45 p's divided into 5 groups all watch the same video of a car crash and were asked how fast were the cars going when they smashed, hit, collided, bumped and contacted. IV- verb used DV-estimated speed. Smashed gave highest estimate. The way the question is worded affects the recall of the event.
   • Memory for an event that has been witnessed is highly flexible. If someone is exposed to new information between witnessing the event and recalling the event, this new information will have effects on what they recall
   • Yuille and Cutshall found that ecological validity was low and research may not generalise to real life EWT. They then did a real life study - they interviewed witnesses where one person was shot dead and another seriously injured. They were asked to recall the event again in a few months time and their accounts were accurate and did not reduce over time as it was a very emotional experience.
   • Easier to distort memory for minor details

6. Reconstructive memory

   • Active process used to reconstructive memories as people don't have total recall.
   • Consists of real elements of memory and gaps in memory that people fill in based on their knowledge of the world (schema)
     • Schemas lead to distortion, explaining why EWT is unreliable.

7. Improvements of the accuracy of EWT

   • Improved interview techniques - Interview p's as soon as possible, questions to aid recall, brief direct questions
   • Cognitive interview - questioning technique used by police to help retrieval - Konniken conducted a meta-analysis of 53 studies and found 34%increase in correct information identified

8. Reliability and accuracy of EWT