eyewitness testimony

• Eyewitness testimony


  An account given by people of an event they have witnessed
• Eyewitness testimony


  • It is an important area of research in cognitive psychology and human memory
  • Juries tend to pay close attention to it and generally find it a reliable source of information
  • However, research has found that it is not always reliable
• Psychological factors that can affect eyewitness testimony

  • Anxiety / Stress
  • Reconstructive Memory
  • Weapon Focus
  • Leading Questions (post-event information)
  • 'other race' effect
• Anxiety/Stress


  • Deffenbacher 1983: the stress-performance relationship follows an inverted-U function proposed by the Yerkes Dodson Curve (1908), meaning performance increases with stress up to an optimal point where it starts to decline
  • Clifford and Scott (1978): people who saw a film of a violent attack remembered fewer details than a control group who saw a less stressful version
  • Witnessing a real crime is probably more stressful than taking part in an experiment, so memory accuracy may be even more affected in real life

  
• Yuille and Cutshall 1986: witnesses of a real life incident (a gun shooting outside a gun shop in Canada) had remarkable accurate memories of a stressful event involving weapons
• Yuille and Cutshall study

  • It illustrates that there are cases of real-life recall where memory for an anxious / stressful event is accurate, even some months later
  • Misleading questions need not have the same effect as has been found in laboratory studies (e.g. Loftus & Palmer)

  
• Reconstructive memory


  • People reconstruct their memories rather than recall them accurately
  • Memories may change to fit our schemas
  • Schemas are capable of distorting unfamiliar or unconsciously 'unacceptable' information in order to 'fit in' with our existing knowledge or schemas, resulting in unreliable eyewitness testimony
• Transformations in reconstructive memory

  • Omissions
  • Rationalisations
  • Familiarisations
• Kent & Yuille (1987): 9 year old children were far more likely than 14 year olds to identify someone from a photo set even when the target person was not present
• Geiselman & Padilla (1988): children were far less accurate when reporting events of a filmed bank robbery than adults
• Factors affecting the accuracy of children's memories

  • Encoding: Children lack developed schemas for many events, which may be an advantage compared to adults whose schemas can cause them to 'see' things that are not actually there
  • Storage: Children's memories are more susceptible to decline than adult memories, affecting memory for descriptions more than actions
  • Retrieval: Children seem to have a greater susceptibility to leading questions than adults
• A biased interviewer can cause children to change their memories through use of leading questions, and repeated questioning often results in children changing their stories as it suggests to them that they are wrong and they want to please the authority figure asking questions
• Avoid use of leading questions or questions that provide misleading information when interviewing children, as research has shown they are more susceptible than adults to both leading questions and misleading information
• Weapons focus


  An eyewitness's concentration on a weapon to the exclusion of other details of a crime, resulting in the witness being able to describe the weapon in much more detail than the person holding it
• Loftus et al. (1987): participants who saw a customer holding a gun in a series of slides tended to focus on the gun and were less likely to identify the customer in an identity parade compared to those who saw the customer holding a checkbook
• Yuille and Cutshall (1986) study contradicts the importance of weapon focus in influencing eyewitness memory
• Leading questions (post-event information)

  The influence of leading questions is illustrated in the classic study by Palmer and Loftus
• 'Other race' effect


  People being less able to accurately recognise people from a different ethnic background to themselves, due to weaker sensitivity for 'other race' faces making them less sensitive to unique identities of 'other race' individuals
• Scheck, Neufeld, and Dwyer (2000): 35% of mistaken eyewitness identifications were white victim witnesses misidentifying black suspects, so eyewitness reliability is questionable
• Brigham, Mass, Snyder, and Spaulding (1982): less recognition accuracy for 'other race' individuals, so accuracy for recognition may limit reliability of eyewitnesses
• Hancock and Rhodes (2008): higher levels of contact with 'other race' groups was associated with a reduction in 'other race' effect and an increase in 'other race' facial recognition accuracy, so 'other race' effect may not always reduce reliability of all eyewitnesses