eyewitness testimony and cognitive interview

• what did Simon and Chabris discover on ewt in 2011?


  37% of Americans believe that the testimony of a single confident witness should be enough to convict a defendant
• case study of Ronald Cotton: eyewitness testimony

  he was convicted in 1986 for raping a 22 year old college student. on the basis of the victim's testimony, Cotton was sentenced to life. the case reopened 11 years later when DNA testing proved that Cotton was innocent and another man was found guilty.
• what are the dangers of eyewitness testimony?

  • memories are unreliable,
  • we often 'reconstruct' memories and fill in gaps,
  • our memories are influenced by schemas- our beliefs and expectations which may be biased,
  • eyewitness testimony can lead to miscarriages of justice,
  • approximately 75% of incorrect convictions were partly due to faulty ewt
• what are the factors affecting eyewitness testimony?

  • anxiety/emotional state at the time of the event,
  • post-event discussion,
  • style of questioning, e.g. leading questions, misleading info
• how does anxiety have an affect on eyewitness testimony?

  • the Yerkes-Dobson 'inverted-U' theory,
  • too little or too much anxiety may negatively affect memory,
  • moderate levels of anxiety produces optimal memory performance
• what was Loftus' research on weapon focus in terms of anxiety? (can be used as a study for anxiety and ewt)


  Loftus found that if a person is carrying a weapon, the witness focuses on this instead of looking at the person's face. anxiety diverts the attention away from other details, stress causes a narrowing of attention (tunnel vision) meaning lost important details
• what did Johnson and Scott research on anxiety and weapon focus in 1976?


  participants in a reception overheard either: low discussion and a man leaving the adjacent room with grease on his hands and a pen, or the same thing but a heated argument and a man leaving with blood on his hands and a letter knife. participants were shown 50 photos and asked to identify the man- 49% correct in the 'no knife' condition, 33% correct in the 'knife' condition
• what were the 2 study's Loftus carried out on anxiety and weapon focus?

  Loftus and Burns, 1982; film of a holdup, different violence levels, identifying the boys in the group- violent version had less recall,

  Loftus, 1987; film of people entering restaurant, gun/no gun but wallet conditions, tracked eye movements of participants- longer fixation on weapon in weapon condition = worse recall
• what are the strengths of the research into anxiety and weapon focus?

  experimental evidence that anxiety can negatively affect ewt, a meta-analysis of 21 students supports this finding (Deffenbacher, 1983), lab experiments can be replicated (reliable), experiments are ethically more acceptable than real life situations,
• what are the weaknesses of the research into anxiety and weapon focus?

  artificial (films, staged events), may not induce fear/stress, possibility of demand characteristics, difficult to operationalise and measure anxiety, individual differences in levels of anxiety, ethical issues, studies may lack ecological validity
• what was Hollin's research into anxiety and ewt in 1981?


  asked 2 groups of students to watch a film of a woman walking home alone. control group- a man asked her for directions, experimental group- a man violently grabbed her arm, forced her against a wall and grabbed her bag. they were then asked to identify him, accuracy was poorer in the violent event
• what was Pickel's research into weapon focus or the element of surprise in 1998?


  claimed that an object does not need to be threatening to cause a narrowing of attention, it needs to be unusual. this was looked into by testing the recall of a man in a hairdressers who either held scissors, a gun, a wallet, or a raw chicken. recall was worst when the gun or the chicken was seen
• what was Yuville and Cutshall's research into weapon focus in 1986?

  there was a gunfight in Canada- a man robbed a store and killed a person (natural study: real life), 21 witnesses were interviewed by police. 4 months later, 13/21 of the witnesses were interviewed by Y and C, they found that memory was very good, 76% for people. witnesses who reported being most upset had the most accurate recall (doesn't support the lab findings as most upset had best recall, not least upset)
• what was Christianson and Hubinette's research into weapon focus in 1993?


  they interviewed 58/110 witnesses to bank robberies in Stockholm. found the witnesses closest to the event had the best recall (e.g. staff), staff directly involved had more accurate recall than bystanders. this shows that lab studies do not always have ecological validity and lack mundane realism. this suggests that anxiety doesn't always negatively affect memory, challenges findings in labs and lab experiments = low ecological validity
• what are the strengths and weaknesses of Christianson and Hubinette's research into weapon focus?

  strengths: high ecological validity, high mundane realism, not artificial, evidence that anxiety may enhance memory for details,

  weaknesses: small sample size limits generalisability, reliance on self-reported anxiety levels (inaccurate), potential selection bias of only those who agreed to participate, ethical issues
• what is misleading info and leading questions?

  misleading info: incorrect info given to an eyewitness following an event. this can take the form of leading questions or be during post-event discussion.

  leading questions: a question that is phrased in such a way that it biases a respondent's reply
• what was Loftus and Zanni's research into leading questions in 1975?

  participants were shown a film of a car crash. they were then asked either: 'did you see THE broken headlight?' or 'did you see A broken headlight?' there was no broken headlight in the film. 17% asked about THE headlight said yes, compares to 7% asked about A broken headlight
• what was Loftus and Palmer's research into leading questions in 1974?

  45 participants were shown a traffic accident. questioned about it, all same questions, apart from they were asked either of: 'about how fast were the cars going when they HIT/SMASHED/COLLIDED/BUMPED/CONTACTED. found that the highest speed estimate was 41mph for 'smashed' and lowest was 31mph for 'hit.' concluded that the verb used influenced the participants' response.
• what did Loftus and Palmer research after the smashed/hit study?

  one week later, they asked participants from the 'smashed' and 'hit' conditions, 'did you see any broken glass?' 32% who had 'smashed' said yes compares to 14% who had 'hit' and said yes. this gives evidence that misleading info after an event can be incorporated into the original memory of the event
• what was Loftus' research into leading questions in 1975?


  showed 150 participants a film of a car accident, divided them into 2 groups. group 1- asked 10 questions consistent with the film, e.g. 'how fast was the white sports car going when it passed the stop sign?' group 2- asked the same questions, except for one, 'how fast was the white sports car going when it passed the barn when travelling along the country road?' there was no barn in the film
• what did Loftus do after the country road film?

  after one week, participants were asked a further 10 questions and both groups were asked, 'did you see the barn?' 2.7% of group 1 said yes, 17.3% of group 2 said yes. so misleading info was added to existing memories
• what did Loftus and Palmer claim after their studies?

  2 kinds of info go into a person's memory of an event:

  info obtained from perceiving an event (e.g. witnessing a video of a car accident),

  info supplied to us after the event (e.g. the question containing hit/smashed)
• what are the strengths and weaknesses of the studies into leading questions?

  strengths: easy to replicate and same findings each time = higher validity, well controlled, demonstrates that the questions asked can influence the response,

  weaknesses: lacks mundane realism (video footage, not real life), participants may find it hard to judge car's speed, participants may not care about the outcome, results may not be ecologically valid
• what did Loftus research on misleading info in 1995?

  she planted false memories of being lost as a child into the participant's memories. she found that 29% of these false memories were recalled by participants
• what did Loftus research on misleading info in 2003?

  she exposed participants to a fake Disney advert of Bugs Bunny (Warner brothers, not Disney) and then asked participants to recall who they had met at Disney. she found that 30% of participants recalled meeting Bugs at Disney if they saw the advert, 40% recalled meeting Bugs if they had seen advert and cardboard figure
• strengths and weaknesses of Loftus' Bugs Bunny study:

  strengths: gives support for claims that misleading info can alter memories, ecological validity- real memories of Disney, 4 controlled conditions,

  weaknesses: demand characteristics could occur, it's not an important area- if linked to a crime and ewt such memories may not be distorted
• what did Shaw find on post-event discussion in 1997?

  found that being interviewed in pairs affected accuracy of recall. witnesses should be interviewed separately so they aren't influenced.
• what research did Gabbert do on post-event discussion in 2003?


  60 participants were in 2 groups. both groups watched a video of a girl stealing money from a wallet. group 1- interviewed individually, group 2- interviewed in pairs and told they had watched same video, when they had been shown different perspectives of the crime, they discussed what they had seen before interviews. they all completed a questionnaire. group 2- 71% of witnesses in the co-witness group recalled info they had not seen and 60% said the girl was guilty
• strengths and weaknesses of Gabbert's research on post-event discussion:

  strengths: well controlled, good population validity (tested university students and older adults), practical application (witnesses should be kept apart),

  weaknesses: witnesses knew they were in an experiment so would've paid closer attention than usual, reasons for memory distortion are not examined (could be due to conformity, lack of confidence, social pressure)
• how to improve accuracy of ewt?

  • no leading questions,
  • cues- for definitive answers,
  • context; state dependant
• what is a standard police interview and it's problems?

  it involves pre-set questions in a specific order, it can be conducted quickly with closed questions,

  problems: often include bias and leading questions, it's formal and may be threatening for witnesses, have led to cases of miscarriages of justice
• what is the cognitive interview?

  derived by Fisher and Geiselman in 1985, aimed to use cues and triggers to help memory, to produce more detailed and accurate ewt
• what is the schedule of cognitive interview?

  1. mentally recreate the context of the original incident ( cue dependency and encoding specificity principle,)
  2. report every detail, even if it appears insignificant,
  3. change perspectives,
  4. recall the event in different orders
• what does the enhanced cognitive interview aim to do?

  • seeks to build trust,
  • avoid disrupting witness,
  • asks open ended questions,
  • gets witness to relax and speak slowly,
  • witness reminded not to guess
• what did Geiselman and Fisher find on cognitive interview in 1985 and 1989?

  Geiselman et al: participants watched a film of violent crime, 48h later police interviewed them using cognitive interview, standard police interview or an interview using hypnosis. found that an average of 41.5 items were recalled using cognitive interview compared to 29.4 with the standard interview and 38 for hypnosis,

  Fisher et al: trained detectives to use the cognitive interview and found that it resulted in 47% more info being recalled.
• strengths of cognitive interview and Geiselman and Fisher's research:

  • lots of supportive research evidence,
  • practical application- CI is now widely used by police,
  • constantly being updated/enhanced,
  • there's a modified version which can be used with children
• weaknesses of cognitive interview and Geiselman and Fisher's research:

  • the CI can result in false memories/incorrect info,
  • time consuming; police may not have time and resources,
  • requires training which is expensive,
  • tiring for interviewer and witness,
  • needs to be carried out soon after the incident,
  • ethical issues; may cause distress,
  • young children may find it confusing