Eyewitness testimony

• What can affect EWT:

  • schemas
  • state and cue dependent forgetting
  • weapon focus
  • stress
  • post event information (leading questions)
• • EWT susceptible to previously learned material
  • Bartlett: identified idea of reconstructive memory
  • Instead of storing an exact replica of events, we blend in elements of our own knowledge and experience to make events more memorable.
  • recreate our memories using our knowledge and experience
  • This is called a schema
• List (86)

  • created list of elements that might occur during shoplifting scenario
  • Asked people to rate events in terms of how likely they were to occur in such an incident
  • Then complied a video showing 8 different shoplifting incidents (incl some elements rated highly and some low
  • Showed video to new set of ppl 1 week later asked them to recall events
  • Findings: ppl more likely to recall high probability events than low probability events. Often reported seeing high probability items that hadn't been included in video
• Tuckey and Brewer (03)

  • Bank robbers are male
  • Wear a disguise
  • Wear dark clothes
  • Demand money
  • Use getaway car and driver
  • When they showed ppl a video of a staged robbery, ppl had better recall for elements of the film that conformed to their schema.
• Cue and state dependent forgetting:

  • forgetting.. when the location changes, our memory is less effective
  • forgetting.. when our emotional state changes, memory is less effective
• • Godden and Baddley's theory of 1975 was to investigate whether a natural environment can act as a cue for recall. They used 18 divers as their participants, ​
  • The divers were asked to learn word lists either on land or underwater, and recall the words either on land of underwater, therefore creating four scenarios. ​
  • They found that the recall was higher when both learning and recall was in the same condition. This shows that memory can be affected by the environment around us.
• Pickel (98)

  • Pickel's experiment in 1998 investigated whether a weapon affected ability to recall.​
  • The participants saw a video of a man walking up to a hairdresser's receptionist with either nothing, a pair of scissors, a gun, wallet or a raw chicken. ​
  • Participants were asked to identify the man in a line up and say what he was doing. ​
  • The unusual objects (raw chicken) had the most effect on recall but not on line-up identification. ​
  • This suggests that it is the unusualness of an object that leads to people focusing on it. This would be true of a weapon as we rarely see them.
• Stress and Anxiety- Loftus (79) weapon effect

  • Field experiment
  • Ppt sat in a reception
  • Person enters the office, closes the door and there is a loud argument.
  • In condition 1- walks out with a pen
  • In condition 2- bloody letter opener, worse recall
• Conflicting evidence about effects of stress and anxiety on witness recall:​

  Lab-based studies show impaired recall in people who’ve witnessed particularly unpleasant or ‘anxiety-inducing situation. Loftus & Burns (1982) – pp shown a violent version of a crime where a boy is shot in the face. Pp had significantly impaired recall for events running up to the violent incident.
• Christianson & Hubinette (1993)

  • “In real life incidents involving high levels of stress, memory can be accurate, detailed and long-lasting”​
  • Surveyed 110 people who’d witnessed 22 genuine bank robberies between them​
  • Some of these people had been bystanders in the bank at the time of the hold-ups, while others had been directly threatened by the robbers​
  • People who’d been subjected to the greatest anxiety, showed more detailed and accurate recall than the onlookers.
• Yerkes- Dodson curve

  
• Nature of the event affecting the testimony:

  • State and context dependent retrieval​
  • Stress!!! Clark (1987) suggest recall of violent crime is more difficult due to stress, and the recall environment is less stressful.
• Stress and arousal - evaluation issues:

  • If Ppts know they are taking part in an expt so may be “under-aroused”. They will not be stressed enough to be able to recall details fully.​ Lacks validity as stress levels aren't realistic (especially in lab studies)
  • Although many people follow the pattern of the Y-Dodson curve, how intensely we feel stress is subjective, so it is hard to generalise this theory to predict performance/recall.
• Loftus et al (78)

  
• Loftus et al (78) results

  
• Post event information affecting the testimony:

  • Adding to the account loftus and Zanni (1975) used ‘leading’ questions to create False memories!​
  • Distortion, Loftus and Palmer (1974) used descriptive terms to distort memories. (smashed Vs hit).
• supporting information:

  • Yuille and Cutshall (1986) testimony in real life situations were very accurate, and resistant to leading Qs. (although only 1 case)]​
  • Demand Characteristics.. McCloskey and Zaragoza (1985)… people want to support the researcher.
• Gender differences in EWT (Butts et al 95)

  • The present investigation examined EW behaviour using two stimulus presentations of dissimilar content and complexity and tests for significance of gender differences.
  • Subjects were 20 male and 20 female college students.
  • No significant gender differences were found between groups on accuracy of recall or resistance to false information on the short term memory task.
• Age of witness:

  • Young children have to act as witnesses as well as adults.
  • Establish if the same factors that affect accuracy in adults, also operate in children.
  • For example, children have been found to be more willing than adults to make a positive identification, but they are often of the wrong person.
• Poole and Lindsey (01):

  Findings-

  When presented with 2 similar sources of information older children were able to separate knowledge whereas younger children could not.
• Conclusions:

  • Important implications for measuring the accuracy of small children's testimony.
  • Small children are very poor at source monitoring.
  • So struggle to extract irrelevant information when delivering an EW account.
• Own age bias Anastasi and Rhodes (06)

  Findings:

  Found people are better to identify people from their own age group than other age groups. Photos of offenders are often used in police procedure. There is validity and application. EWT not reliable as we all have same age bias.

  • Contact- more contact we have with ppl of a particular group the better our memory for such individuals.
  • Experience- less experience we have with a particular age -group the greater the own age bias.
  • Expertise- more regularly we see a group of individuals, the more expertise we have to process those faces.

  
• Flin et al (92)

  • Found that long delays effect the accuracy in young children.
  • Gordon et al (01) found that children susceptible to suggestion.
  • Old people also prone to errors in recall.
• Age differences in source forgetting: effects on reality monitoring and on eyewitness testimony (Cohen and Faulkner 1989)

  • Old people cant always accurately recall where they have seen something.
  • Old people can be misled by false information.
• Individual differences:

  • Some people more susceptible than others.
  • According to Tomes and Katz (97) these people share certain characteristics.
  • They generally have poorer recall for the event.
  • They score high on measures of imagery vividness.
  • They have high scores on measures of empathy.