Topic Summaries

Factors affecting the accuracy of eye-witness testimony .

A-Level > Psychology > AQA > A-Level Psychology Topic Summaries > Memory > Factors affecting the accuracy of eye-witness testimony .
Previous Module
Next Module

Addiction

  • Leading questions: are question that are phrased in a way that suggests or guides the respondent towards a particular answer rather than allowing for an unbiased response. A leading question can alter or distort memory recall by introducing information that may not have originally been present, demonstrating that memory is not a perfect recording, but can be influenced, reconstructed, or even contaminated by suggestion.
    • 👥 Loftus and Palmer (1974) investigated the impact of question phrasing on eye-witness testimony. They conducted a lab experiment with 45 American students. They were shown a video of a car crash and asked the question ‘How fast were the cars travelling when they _____ each other?’ with variations of the term ‘crashed’ (i.e.smashed, hit, collided, bumped, or contacted). They discovered that when students were asked the question with the verb ‘smashed,’ they guessed a higher mean speed than those who were asked with the verb ‘contacted.’ They concluded that the phrasing of a question can influence a participant’s memory of an event.
    • Evaluation of leading questions:
      • Practical application: this research helped to reform police questioning techniques and discourage the use of leading questions – instead they use cognitive interview techniques to prevent wrongful convictions.
      • Internal validity: this was a lab experiment so had high internal validity as it took place in a highly controlled environment. They had control over extraneous variables and could establish a cause and effect.
      • External validity: because the lab is an artificial environment, there was no emotional impact or consequence over answer given, so results may not be generalisable to the real world.
  • Post-event discussion: when witnesses of a crime discuss the event with one another, their eye-witness testimony can become distorted as they combine misinformation from other witnesses with their own memory.
    • 👥 Gabbert et al.(2003) conducted a lab experiment showing a video of a girl stealing money from a wallet. The participants were either tested in peers (co-witnesses) or individually. The participants were told they were watching the same video, but they were from different perspectives. The co-witness groups discussed the event afterwards whereas the individual (control) group didn’t. They discovered that 71% of the co-witness group mistakenly recalled information they had not seen. In the control group without discussion, the figure of misinformation was 0%. They concluded that post-event discussion can affect a person’s memory of an event and that witnesses will go along with each other.
    • Evaluation of post-event discussion:
      • Practical application: this informs the legal system and practice of discouraging jurors from discussing the case outside of the courtroom.
      • Internal validity: this was a lab experiment so was highly controlled and standardised, establishing cause and effect.
      • External validity: a lab experiment doesn’t reflect real world eye-witness testimony.
  • Anxiety: has strong emotional and physical effects on a person, but it’s unclear whether it has a positive or negative effect on recall of eye-witness testimony.
    • Positive effect: 👥 Christianson and Hubinette (1993) investigated if anxiety increases or decreases the accuracy of eyewitness testimony. They interviewed 58 real victims of a bank robbery. These people were either directly threatened or just witnesses. They discovered that those who had been directly threatened had significantly better memories of the event than the witnesses. They concluded therefore that anxiety increases the accuracy of eyewitness testimony.
    • Negative effect: 👥 Johnson and Scott (1976) investigated the effects of anxiety in the accuracy of eyewitness testimony using a lab experiment. Participants were placed in one of two conditions where a person was carrying some thing intended to provoke high anxiety (weapon), or low anxiety (pen). They then had to identify the person who left the room from fifty photographs. They discovered a 49% accuracy rate in the low anxiety condition as opposed to 33% in the high anxiety condition. They concluded that anxiety caused weapon-focus as the witness only concentrated on the weapon and not the person.
    • Yerkes Dodson Law: is a principle that peak task performance comes at an intermediate level of stress. Too much or too little stress will cause a drop in performance. Therefore, an intermediate level of anxiety could be argued to be optimal for accuracy of eye-witness testimony.
      • Harm: these investigations into the effect of anxiety on accuracy of eye-witness testimony may have caused psychological harm to their participants which breaks ethical research guidelines.
      • Low external validity: lab experiments are harder to generalise to real world situations. In a real, high anxiety, situation, people may act differently due to shock or the fact that there may be consequences of their testimony.
  • The cognitive interview: developed by 👥 Fisher et al (1990), who watched real police interviews and concluded that there were issues with the standard interview. Cognitive interviews had open-ended questions, did not interrupt participants, and thus had more retrieval paths. Standard interviews had closed, direct questions, often interrupted participants, and thus had fewer retrieval paths.
    • 👥 Fisher and Geiselman (1992) developed the cognitive interview which is a technique used by police to interview witnesses after they’ve seen a crime or accident to help facilitate the most accurate and detailed memory possible
    • Features of the cognitive interview:
      • Recall everything: report all the details even if it seems insignificant. This may act as a trigger to an overlooked memory. For example, “Please tell us everything that happened, from start to finish.”
      • Context reinstatement: ask people to mentally place themselves at the scene of the event again and remember the environment exactly as it was, thereby triggering more detailed memories. For example, “Imagine you’re back at the scene of the crime – what was the weather like?”
      • Recall in reverse: ask people to recall the events in a different order. This prevents them from saying what they expect to happen next in the list of events as it’s harder to lie in reverse.
      • Recall from a different perspective: asked people to place themselves in a different person’s perspective. This allows a more holistic view to be produced and prevents them from saying what they might expect to happen.
    • Fisher et al.reported results of 50 lab experiments that compared the cognitive interview and the standard interview. Participants were shown a film of a staged crime and were either given a cognitive or standard interview. Participants who received the cognitive interview recalled between 25–100% more correct information. 

Unlock Factors affecting the accuracy of eye-witness testimony .

Subscribe to SnapRevise+ to get immediate access to the rest of this resource.

Premium accounts get immediate access to this resource.

Previous Module
Next Module