Eyewitness Testimony
Eyewitness Testimony
Eyewitness testimony (EWT) is the account a witness gives in court about a crime or event they observed. Research shows that EWT can be unreliable and influenced by several factors.
Factors Affecting EWT Accuracy
1. Leading Questions
A leading question is one that suggests a particular answer or contains misleading information.
Key study — Loftus and Palmer (1974):
- Participants watched a film of a car accident, then answered questions about it
- The critical question was: "How fast were the cars going when they [verb] each other?"
- The verb was changed for different groups: smashed, collided, bumped, hit, contacted
| Verb | Average speed estimate |
|---|---|
| Smashed | 40.5 mph |
| Collided | 39.3 mph |
| Bumped | 38.1 mph |
| Hit | 34.0 mph |
| Contacted | 31.8 mph |
- The verb "smashed" led to higher speed estimates than "contacted"
- In a follow-up, the "smashed" group were more likely to report seeing broken glass (there was none)
- Conclusion: leading questions can distort memory, not just influence the answer — they actually change what the witness remembers
2. Post-Event Discussion
- When witnesses discuss the event with each other or are exposed to media coverage, their memories can be contaminated
- They may incorporate information from others into their own memory without realising
- This is called memory conformity or the co-witness effect
- Gabbert et al. (2003): 71% of witnesses who discussed the event reported details they had not actually seen but had heard from another witness
3. Anxiety
- Anxiety can either improve or impair EWT accuracy, depending on the level and the situation
Key study — Johnson and Scott (1976) — Weapon Focus Effect:
- In the low-anxiety condition, a man walked through a waiting room carrying a pen with grease on his hands
- In the high-anxiety condition, a man walked through carrying a bloody knife after a heated argument was heard
- Participants in the knife condition were less accurate at identifying the man in a line-up (33% vs 49%)
- Explanation: anxiety causes witnesses to focus on the weapon (the source of threat) rather than the person's face — this is the weapon focus effect
Yerkes-Dodson Law:
- Performance (including memory accuracy) follows an inverted-U curve
- Very low anxiety = poor attention and poor recall
- Moderate anxiety = optimal attention and best recall
- Very high anxiety = attention narrows to the threat (weapon focus), and recall of other details suffers
The Cognitive Interview
The cognitive interview (CI) was developed by Fisher and Geiselman (1992) to improve the accuracy of EWT. It is used by police forces as an alternative to standard interviews.
The Four Techniques
| Technique | How It Works |
|---|---|
| Mental reinstatement of context | The witness mentally returns to the scene — recalling the environment, weather, emotions and sounds. Based on context-dependent retrieval cues |
| Report everything | The witness reports every detail, no matter how trivial or irrelevant it seems — minor details may trigger more important memories |
| Recall in different orders | The witness describes events in reverse or from a different starting point — prevents the use of schemas (pre-existing expectations) that might distort recall |
| Change perspective | The witness describes the event from the perspective of another person who was present — helps access information that might otherwise be overlooked |
Strengths of the Cognitive Interview
- Research support: meta-analysis by Kohnken et al. (1999) found the CI produced 34% more correct information than standard interviews
- Real-world application: used by police forces in the UK and worldwide
- Based on psychological theory — retrieval cues and preventing schema-driven errors
Weaknesses of the Cognitive Interview
- Time-consuming — takes longer than a standard interview; police may lack time
- Training required — officers need extensive training; many may not use all four techniques
- May increase incorrect information — witnesses report more details overall, including some inaccurate ones
- Not suitable for all witnesses — young children and those with cognitive difficulties may struggle with the techniques
Exam Tips
- Know Loftus and Palmer (1974) in detail — it is the most commonly tested study in this topic
- Understand the weapon focus effect and how anxiety affects EWT
- Be able to describe all four cognitive interview techniques and link each to psychological theory
- For AO3: evaluate EWT research — most studies use lab experiments (high control but low ecological validity; participants know they are in a study)
- For longer questions, consider whether EWT should be relied upon in court — what are the alternatives?