Factors Affecting Accuracy of Eyewitness Testimony

• Leading Questions:

  :) practical applications

  > the principle of the theory, that leading questions can influence EWT, has led to the development of the cognitive interview - avoids the use of leading questions and uses techniques to improve accuracy of EWT

  > e.g. recall everything

  > important part of applied psychology

  discussion - economic implications
• Leading Questions:

  :( lacks mundane realism

  > Loftus and Palmer use the artificial task of watching a video of a car crash - difficult to generalise the findings as Foster found that eyewitnesses of a real event understand the consequences of giving inaccurate information

  > lowers external validity
• Post-Event Discussion:

  :) RTS Skagerberg and Wright

  > showed participants two versions of a video of a mugging - mugger's hair was dark brown or light brown

  > participants discussed the clips in pairs (each having seen different versions) - found that they reported a 'blend' of the two, suggesting the mugger had 'medium brown hair' rather than dark or light

  > supports because demonstrates memory contamination
• Post-Event Discussion:

  :( demand characteristics

  > controlled environment with unrealistic tasks, such as watching clips of crimes - it is possible that participants are able to pick up on clues from the task, so may change their response to fit the aims of the research (help or hinder researcher) e.g. changing their response to match their co-witness after discussing the clip

  > lowers internal validity
• Anxiety:

  :) RTS Valentine and Mesout

  > used an objective measure (heart rate) to divide participants into high and low anxiety groups

  > both took part in the London Dungeon Labrinth (high anxiety event) and were then asked to immediately recall physical details of the actor from the event - high anxiety lowered the accuracy of EWT significantly

  > high anxiety does have a negative effect on recall
• Anxiety:

  :( RTC Christianson and Hubinette

  > interviewed 58 real-life witnesses of a bank robbery: some had been directly threatened (bank teller - high anxiety) and others were bystanders (customers - low anxiety)

  > recall was more than 75% accurate across all witnesses, but those who had been directly threatened had even more accurate accounts - contradicts that anxiety reduces accuracy of EWT

  discussion - they were interviewed several months after so effect of anxiety may have been overwhelmed by other factors, such as post-event discussion
• Anxiety:

  :( Johnson and Scott not truly measuring anxiety

  > participants may have focused on the weapon because they were surprised rather than scared

  > Pickel - experiment using scissors, a handgun, a wallet or a raw chicken as the handheld items in a hair salon video (where scissors would be high anxiety but low unusualness)

  > EWT accuracy was significantly lower in the high unusualness conditions (chicken and handgun) - suggests that weapon focus is due to surprise rather than anxiety, so does not explain effect of anxiety on EWT
• Anxiety:

  :)/( Yerkes-Dodson Law

  > different levels of anxiety affect the accuracy of EWT - too much or too little anxiety results in poor EWT recall, but if you reach an optimum level of anxiety, the accuracy is high

  > explains the differences between Johnson and Scott and Christian and Hubinette's findings - participants in Christian and Hubinette's study may have been at an optimum level of anxiety = more accurate EWT

  > resolves the contradiction and validates that anxiety does affect EWT