What is eyewitness testimony?

Eyewitness testimony is a key element in many legal cases, often helping to identify and convict individuals involved in crimes. It involves a person who has seen an event providing a description or identification based on their memory. This testimony can be given in written statements to the police or as verbal evidence in court.

However, while eyewitness testimony is frequently relied upon by juries and courts, it is not always accurate. This can lead to serious consequences, such as the wrongful conviction of innocent people. For example, in the case of Jean Charles de Menezes, who was shot by police at Stockwell tube station in 2005, eyewitness accounts initially described him vaulting over barriers and wearing a bulky jacket, but later evidence showed he walked calmly and wore a light jacket. This mismatch highlights how eyewitness recall can be flawed, raising questions about its reliability in high-stakes situations.

Factors contributing to the unreliability of eyewitness testimony

Several psychological factors can distort what eyewitnesses remember, making their testimony less trustworthy. These factors often stem from how memory works, including how information is encoded, stored, and retrieved. Memory is not like a video recording; instead, it is actively constructed and can be influenced by various elements.

Reconstructive memory

• Reconstructive memory is the process where people rebuild past events using fragments of actual memories combined with general knowledge and expectations.
• This can lead to inaccuracies because individuals fill in gaps with assumptions rather than facts.

Schemas play a central role here:

• Schemas are mental frameworks or organised packets of information based on past experiences, which help us make sense of the world but can also introduce biases.

• For instance, if someone expects a perpetrator to fit a certain stereotype (such as being male), they might unconsciously alter their recall to match that expectation.

• This concept explains why eyewitnesses might provide distorted accounts, as their memories are reconstructions influenced by personal beliefs rather than pure facts.

Post-event information

• Post-event information refers to details encountered after an event that become integrated into a person's memory of the original incident.
• This can alter recall, especially if the new information is misleading.
• Leading questions, which are questions phrased in a way that suggests a particular answer, are a common source of post-event information.
• They can implant false details into memory, making witnesses believe they saw something they did not.
• This factor shows how external influences after an event can compromise the accuracy of eyewitness testimony.

Stress and anxiety

• Stress is a state of mental or emotional strain, often triggered by threatening situations, while anxiety is a feeling of worry or unease.

• High levels of stress or anxiety during an event can impair memory by narrowing attention and reducing the ability to process details.

• For example, in traumatic situations like crimes, witnesses might focus on immediate threats, missing other important information.

• This distraction can lead to poorer recall later, making testimony less reliable.

Weapon focus effect

• The weapon focus effect occurs when the presence of a weapon in a crime draws a witness's attention away from other details, such as the perpetrator's appearance.

• This happens because the weapon is perceived as a threat, capturing focus and reducing the encoding of surrounding information.

• As a result, witnesses might remember the weapon vividly but struggle to describe the attacker or other aspects of the scene, contributing to unreliable testimony.

Key research on reconstructive memory: Bartlett's War of the Ghosts study

Frederic Bartlett's 1932 study, known as War of the Ghosts, investigated how cultural schemas influence memory reconstruction.

He used a Native American folk tale that was unfamiliar to participants to see how they recalled it:

• Results - Participants adapted the story into something more relevant to their cultural expectations.
• Conclusions - Memory is an active reconstruction influenced by schemas, leading to distortions.
• Implications - This supports the idea that eyewitness testimony can be unreliable due to cultural or personal assumptions filling in memory gaps.

Key research on post-event information: Loftus and Palmer's study

• Aim - Elizabeth Loftus and John Palmer (1974) examined how leading questions affect eyewitness recall of a car accident, demonstrating the impact of post-event information.

• Findings - Leading questions, such as using the word 'smashed', could distort memory by incorporating post-event information, leading to false recollections.

• Implications - This explains why eyewitness testimony might be unreliable in legal settings where questioning can influence recall.

Contrasting research on eyewitness accuracy: Yuille and Cutshall's study

• Aim - John Yuille and Judith Cutshall (1986) conducted a field study on real witnesses to a robbery, providing evidence that eyewitness memory can sometimes remain accurate despite time delays.

• Findings - Witnesses' accounts remained highly accurate over time, with little change in details.

• Implications - This suggests that in real-life, high-stress events, eyewitness memory can be reliable and resistant to distortion, contrasting with lab-based findings like Loftus and Palmer's.

Research on stress and anxiety: Clifford and Scott's study

• Aim - Brian Clifford and Ray Scott (1978) explored how violence affects memory recall, focusing on stress as a distracting factor.

• Findings - Those who saw a violent film clip recalled fewer details than those who saw a non-violent one.

• Implications - This supports the idea that high stress from violence impairs memory by distracting attention, leading to poorer eyewitness recall.

Improving eyewitness testimony: The cognitive interview

The cognitive interview is a technique developed to enhance the accuracy of eyewitness recall by using psychological principles to maximise memory retrieval without introducing distortions. It aims to provide multiple retrieval cues to access more details from memory.

Key features of the cognitive interview:

• Witnesses are asked to recall events in different orders.
• Witnesses are asked to recall events from different perspectives to help with recall.
• This method has been adopted by police forces to improve the quality of eyewitness statements, potentially leading to more accurate convictions or acquittals.

Research on the cognitive interview: Milne's evaluation

• Aim - Rebecca Milne (1997) reviewed studies on the cognitive interview to assess its effectiveness.

• Findings - The cognitive interview did not consistently lead to more recalled information than other methods, questioning its overall value.

• Limitations - It can be time-consuming and may cause distress by making witnesses relive events.

• Ethical concerns - Ethical concerns limit true experimental testing on real cases, as further questioning could alter memories and affect legal outcomes.