eye-witness testimony

• reconstructive memory

  we don't remember information like a tape recording, we remember bits and fill the rest in based on our schemas' stereotypes and scripts which can lead to false memories. this can be affected by ~

  • anxiety
  • misleading information - post-event discussion and leading questions
• leading question - a question that encourages the witness to answer a certain way due to the subtle introduction of new information
• car crash video study

  loftus + palmer - showed participants a video of a car accident and asked them to estimate how fast a car was travelling when it [verbed] with the second car

  • contacted, bumped, collided, hit or smashed
  • the most violent verb (smashed, 40.8 mph) gave an estimate 9 mph faster than the least violent verb (contacted, 31.9 mph)

  this supports the idea of leading questions because the verb used altered the memory of the event and changed what the participants thought they saw
• loftus + palmer evaluation

  - lacks mundane realism

  • participants were aware they were about to witness an accident
  • real life crimes are more important to us so we may remember them more accurately
  • witnessing real accidents may be more stressful which affects memory

  - contradictory evidence in yuille + cutshall's gunshop robbery study
• gunshop robbery

  yuille + cutshall - interviewed witnesses to a real gunshop robbery asking for details of the event and a stress rating on a 7-point likert scale

  • responses didn't alter in response to leading questions
  • the participants who reported the highest stress levels had the most accurate recall

  this suggests that misleading information doesn't impact the recall of real crime memories as the witnesses didn't change their responses after leading questions. it also suggests that anxiety positively impacts the memory of an event as those who reported the most stress were the most accurate
• yuille + cutshall evaluation

  + high mundane realism - interviewed real witnesses to a real crime so had high external validity

  + important as challenges loftus + palmer's car accident research

  - the case was shocking and unusual which means it may not be generalisable

  - the case was very unique and so probably won't occur again - unreliable and unscientific as can't be repeated
• explanations of misleading information and memory

  • substitution explanation - the leading questions or new information changes participants' memory of events as the information is accommodated into their schema
  • response bias - participants' responses don't reflect a change to their memory, but they change their response in order to fit the verb/give what they believe is the correct answer
• post-event discussion - when witnesses of an event discuss what they saw with one another, which contaminates their individual memories of the event
• post event discussion research

  gabbert et al - pairs of participants were shown videos of the same crime but from different viewpoints, and then given the opportunity to discuss what they saw

  • 71% reported remembering information they couldn't have known from their vantage point
  • compared to 0% in the control group with no discussion

  gabbert argues this is memory conformity due to contamination and shows that misleading information impacts people's recall of an event
• evaluation of misleading information

  + useful application - relates to real life witness testimonies and can help inform courts on how to apply testimonies to cases

  - artificial scenarios are unrepresentative of real crime cases

  - demand characteristics

  - individual differences in participants eg. own age bias

  - contradictory evidence - bodner - the effects of post-event discussion can be reduced if participants are warned of its effects, or if they are warned that what they hear from others is hearsay - gabbert's results are exaggerated
• anxiety - state of emotional and physical arousal which has a number of effects, including influencing memory. this is important as many events witnessed by eye witnesses are anxiety-inducing, and the impact of anxiety on memory can be both positive and negative
• anxiety - pen vs knife

  johnson + scott - participants believed they were about to take part in a lab experiment and were in a waiting room when they overheard a heated argument followed by a man exiting a room holding either ~

  • a pen and ink on his hands
  • a knife and blood on his hands
  • when asked to pick the man from 50 photos participants were more accurate in the low-anxiety condition (49% correctly identified) than the high-anxiety condition (33% correctly identified)

  this suggests that anxiety has a negative effect on recall and offers supprt for the tunnel theory
• tunnel theory

  tunnel theory of memory - in stressful situations our attention narrows to focus on the aspect of the situation that is the most anxiety-inducing and/or threatening

  • reduces recall of the wider situation, which is often needed in testimonies
  • supported by johnson + scott's knife vs pen study, which found that participants were more focused on the knife than the pen and so were less able to find the man's face
• johnson + scott evaluation

  + supports the tunnel theory

  + high mundane realism - the participants were unaware of the experiment and so didn't change their behaviour

  - may be offset by an unrealistic scenario

  - ethical issues - deception and lack of informed consent

  - contradictory evidence - pickel suggested results may be caused by unusualness
• hair salon + unusualness

  pickel - showed participants a video of a man entering a hair salon with one of four objects, taking money from a receptionist and leaving before asking them questions about what they saw

  • raw chicken, gun, wallet and scissors
  • found recall of the situation was worse for both the raw chicken and the gun

  this research suggests that it is the unusualness of an object that causes tunnel vision and that anxiety-inducing objects are also the most unusual in a situation. this suggests that the effect of anxiety on memory may have been exaggerated
• the anxiety bell curve

  yerkes-dodson curve - suggests that anxiety increases the performance of memory to a certain extent, after which it decreases recall

  • there is an optimal point which is unique to each individual
  • is able to explain instances of anxiety both increasing and decreasing the accuracy of recall
  • suggests all other theories of memory and anxiety are reductionist

  
• general anxiety and memory evaluation

  - pickel's study of unusualness

  - field studies lack control

  - ethical issues - psychological harm of reliving trauma

  - yerkes-dodson curve is too simple - anxiety is complex and has many elements that the curve doesn't involve

  - demand characteristics and unrealistic situations in lab studies

  - studies of anxiety often only involve low and high anxiety conditions

  • overcome by parker - interviewed people who had been affected by hurricane andrew (1992) and defined anxiety with damage done to homes and found a link between damage and recal
• the cognitive interview

  fisher and gueiselman - developed an interview technique designed to apply psychological theories of memory to police investigation to maximise the amount of correct information recalled. consists of ~

  • report everything
  • mental or physical reinstatement to provide a context dependent cue
  • reporting events in a different order to how the occured to prevent people reporting expectations
  • recalling the incident from another person's perspective to disrupt schema
• research into the cognitive interview


  • kohnken et al - metaanalysis that found 34% increase in correct information recalled when the cognitive interview was used compared to a standard interview
  • milne and bull - compared the four techniques and found that each technique alone improved accuracy but a combination of recall everything and mental reinstatement is the most effective
  • fisher et al - developed technique to make the enhanced cognitive interview which focused on social aspects of the interview such as eye contact, minimising distractions and using open-ended questions
• cognitive interview evaluation

  + supporting evidence that proves its efficacy and usefulness

  - training police in the technique is time-consuming, and delivering the technique also takes much longer than a standard interview

  - research found that the technique increases the amount of incorrect information recalled as well as correct information

  - investigating its efficacy is difficult as the technique is applied differently by different police forces and it's very difficult to compare these different versions