Eyewitness testimony: Anxiety

• what are the two studies related to the effect of anxiety on eyewitness testimony?

  Johnson and Scott and yuille and cutshall
• procedure of Johnson and Scott: anxiety had a negative effect

  • participants sat in waiting room thinking they were taking part in a lab study
  • each participant heard an argument in the next room: low-anxiety condition (man then walked through room carrying a pen with grease on his hands) and high-anxiety condition (heated argument accompanied by smashing glass. man then walked through room holding a paper knife covered in blood)
  • participants later asked to pick the man from a set of 50 photographs.
• what happened in the low-anxiety condition of Johnson and Scott's study?

  a man walked through the room holding a pen with grease on his hands.
• what happened in the high-anxiety condition of Johnson and Scott's study?

  the heated argument was accompanied by the sound of breaking glass. a man then walked through the room holding a paper knife covered in blood.
• findings & conclusions of Johnson and Scott: anxiety has a negative effect

  • 49% of participants in low-anxiety condition able to identify him
  • 33% of high-anxiety participants able to identify him
  • tunnel theory of memory argues that a witness' attention is on the weapon (weapon focus), because it is a source of danger and anxiety.
• what is it called when a witness' attention is on the weapon?

  weapon focus
• did Johnson and Scott say anxiety had a negative or positive effect?

  negative effect
• did yuille and cutshall say anxiety had a negative or positive effect?

  positive effect
• procedure of yuille and cutshall: anxiety has a positive effect

  • real-life crime, gun shop owner shot a thief dead
  • 21 witnesses, 13 agreed to participate
  • participants interviewed 4-5 months after the incident. accounts compared to the police interviews at the time of the shooting
  • witnesses rated how stressed they felt at the time of the incident
• findings & conclusions of yuille and cutshall: anxiety has a positive effect

  • witnesses very accurate and there was little change after 5 months
  • some details less accurate, e.g. colours of items, and age/weight/height
  • participants who reported the highest levels of stress most accurate (88% compared to 75% for the less stressed group)
• what are the two ways to explain the contradictory findings?

  'inverted U' theory and affects memory
• 'Inverted U' theory


  yerkes and dodson argue that the relationship between performance and arousal/stress is curvilinear rather than linear.
• who proposed the inverted U theory


  yerkes and dodson
• affects memory


  deffenbacher found that lower levels of anxiety did produce lower levels of recall accuracy. recall accuracy increases with anxiety up to an optimal point. a drastic decline in accuracy is seen when an eyewitness experiences more anxiety than the optimal point.
• limitation of anxiety: ethical issues

  creating anxiety in participants is potentially unethical because it may subject people to psychological harm purely for research purposes. so real-life studies are beneficial: psychologists interview people who have already witnessed an event, so there is no need to create it. ethical issues don't challenge the findings of studies (e.g. Johnson and Scott) but they do raise questions about conducting such research.
• limitation of Johnson and Scott's study: may test surprise not anxiety

  participants may focus on a weapon because they are surprised at what they see rather than because they are scared. pickel used scissors, handgun, wallet and raw chicken as hand-held items in a hairdressing salon. EWT accuracy was poorer for high unusualness (chicken and handgun). so the weapon focus effect is due to uniqueness rather than anxiety/threat and therefore tells us nothing specifically about the effects of anxiety on EWT.
• limitation of field studies: lack control of variables

  real-life witnesses are interviewed sometime after the event. many things happen to them in the meantime that researchers cannot control. examples: eyewitnesses discuss the event with others; they read or view accounts in the media; the police interview may influence their memory. these extraneous variables may be responsible for the (in)accuracy of recall, not anxiety. it is difficult to isolate the variables.
• limitation: demand characteristics

  most participants in controlled lab studies are aware they are watching a filmed (and staged) crime for a reason to do with a study. they may work out that they will be asked questions about what they have seen, they may give responses which they believe to be helpful to the researcher. so the research is not measuring the accuracy of EWT and this reduces the validity of research investigating the effects of anxiety