Eye witness testimony

• Both research tasks were artificial, so they lack ecological validity
• This research has led to a change in the way the police interview witnesses
• Eyewitness Testimony

  The ability of people to remember the details of an event, such as a crime, which they have observed
• Misleading Information


  Incorrect information given to the witness after the event. This can be via post-event discussion or leading questions
• Post-Event Discussion

  Where more than one witness discuss the event that happened. Witnesses may have slightly different accounts which could influence others
• Gabbert et al. (2003)

  1. Participants watched a video of the same crime but filmed from different points of view

  2. Participants then discussed what they witnessed before completing a recall test

  3. 71% of participants mistakenly recalled aspects of the crime they didn't even witness but had picked up from other participants
• Leading Questions

  A leading question is a question which, because of the way it is phrased, suggests a certain answer
• Loftus and Palmer (1974)

  1. Aim: to test whether leading questions could affect EWT accounts

  2. 45 American students were participants and each was assigned to 1/5 conditions

  3. In each condition, participants watched a video of a car accident and then were asked "How fast were the cars going when they
• Response Bias

  The wording of the question influences how the witness decides to answer and does not affect their memories
• Substitution

  The wording of the question alters the person's memory
• They were lab experiments, which means demand characteristics come into play
• Both experiments were high in reliability
• Anastasi and Rhodes (2006) found that those aged 18-25 and 35-45 were more accurate that those aged 55-78. However, all participants were more accurate when identifying someone their own age (own age bias)
• Anxiety

  A state of emotional and physical arousal. The emotions include having worried thoughts and feeling tense. Physical changes include increased heart rate and sweatiness
• Johnson and Scott (1976) - Negative Impact

  1. Participants watched a video of the same crime but filmed from different points of view then discussed what they witnessed before completing a recall test

  2. 71% of participants mistakenly recalled aspects of the crime they didn't even witness but had picked up from other participants

  3. 49% of participants in the low anxiety condition were able to pick out the man out from a set of 50 photos

  4. 33% of participants in the high anxiety condition were able to pick the man out from a set of 50 photos
• This has become to be known as the weapon focus effect
• Yuille and Cutshall (1986) - Positive Impact

  1. There was a shooting at a gun shop in Vancouver, Canada and 13/21 of the witnesses agreed to be participants

  2. Interviews were held after 4-5 months. These were compared with original interviews

  3. Accuracy was determined by the number of details reported

  4. Also asked to rate their stress levels at the time on a 7-point scale and if they had any emotional problems since

  5. Witnesses were very accurate with their accounts, with little change after 4-5 months

  6. Some inaccurate details were the colour of items and age/height/weight estimates

  7. The participants who reported the highest levels of stress were the most accurate (88%) when compared with the less-stressed group (75%)
• Yerkes-Dodson Law

  • Lower levels of anxiety produce lower levels of recall accuracy
  • There is an optimal amount of anxiety which will have maximum accuracy
  • If anxiety is higher than this, then accuracy will decline
  • The relationship between emotional arousal and performance looks like an inverted U
• Weapon focus may not be relevant: Johnson and Scott's study may be testing surprise (unusualness) rather than anxiety or fear
• Inverted U explanation is too simplistic: anxiety is difficult to define and measure accurately. It has many elements (physical, cognitive, behavioural, and emotional) and the inverted U only accounts for one (physical)
• Field studies lack control, reducing reliability
• Field studies are high in ecological validity
• Ethical issues: psychological harm
• Cognitive Interview

  • The elements of the Cognitive Interview:
  • 1. Report everything
  • 2. Reinstate the context
  • 3. Change perspective
  • 4. Reverse the order
• Report Everything

  Witnesses are encouraged to talk about every single detail even if it might seem insignificant to them or they're not confident. Information that might seem trivial could trigger other important memories.
• Reinstate the Context

  The witness should return to the original crime scene psychologically and imagine the environment. This could be asking about the weather or surroundings. This is related to context-dependent forgetting.
• Change Perspective

  Witnesses should try recalling the event from someone else's perspective. This could be the perpetrator's point of view or another witness'.
• Reverse the Order

  Events should be recalled in different chronological orders to the original sequence. This is done to prevent people from reporting their expectations of how the event happened and to prevent dishonesty.
• Fisher et al. (1987) - The Enhanced Cognitive Interview

  1. Developed additional elements to focus on the dynamics of interaction. The interviewer needs to know when/how to:

  2. Establish eye contact

  3. Reduce anxiety

  4. Minimise distractions

  5. Get the witness to speak slowly

  6. Ask open-ended questions
• It is time consuming: takes more time than a standard police interview
• Kohnken et al. (1999) - Meta-Analysis

  1. ECI: consistently provided more correct information than the standard interview

  2. 81% increase in accurate information, 61% increase in incorrect information
• Some elements may be more valuable than others: Milne and Bull (2002), each element is equally valuable, but if you used a combination of report everything and reinstate the context, this produced better recall