anxiety: factors affecting EWT accuracy

• how does anxiety have a negative effect on recall? (weapon focus)


  anxiety creates psychological arousal in the body, preventing us from paying attention to important cues so our recall is worse. One approach to studying EWT and anxiety is to look at the effect of the presence of a weapon which creates anxiety, leading to focus on weapon, reducing witness’s recall for other details of the event
• who did research on weapon focus effect?

  Johnson and Scott 1976
• what did Johnson and scott research and how? 1976


  weapon focus effect- in a lab experimen- while seated in a waiting room participants were placed in two condition- low anxiety, overheating a casual convo next door and seeing someone holding a pen and grease , and a high anxiety condition, where they heard a heated arguement, breakimg glass and someone walked past them with a bloody knife.

  • those in low anxiety correctly coukd identify the man with the pen, 33% of those who saw the bloody knife correctly identified the man.
• what did Johnsons and Scot’s study show?

  the tunnel theory of memory— argues ppl have enhaced memory for central events.
• what is the tunnel thoery?

  anxiety narrows attention onto one aspect of a scene, (eg. a weapon like in Johnson’s and Scott’s study) like tunnel vision, meanidn tku won’t be able to recall much else.
• how does anxiety have a positive effect on recall.


  witnessing a stressful event creates anxiety through psychological arousal in the body. The flight or fight response is triggered , increasing alertness. This can improve our memory of the event as we're more aware of cues in the situation.
• how was positive effect of anxiety on recall proved? (procedure)

  Yuille and cutshall 1986 conducted a study of an actual shooting in a gun shop in vancouver, Canada. The shop owner shot the thief dead. Thee were 21 witnesses- 13 of which partook in the study. The accuracy of their account was measured by number f details provided in each account. They were also asked how stressed they felt at time of the incident ( 7 point scale) and asked if they had any emotional problems since, e.g. sleeplessness
• how does anxiety have a positive effect on recall? (Yuille + Cutshall)

  Findings of procedure

  witnesses were very accurate in their accounts and there was little change in amount or accuracy after 5 months- though some details were less accurate, such as colours of items or height/weight/age estimates. The participants with highest levels of anxiety were more accurate (88% compared with 75% of less-stressed group). Suggests anxiety doesn't have a detrimental effect on eyewitness memories in real-life context and may even enhance it.
• explanaton to contradictory findings?

  yerkes-dodson law
• What is the Yerkes-Dodson Law?

  It describes the relationship between emotional arousal and performance as an upside-down "U".
• What did Deffenbacher (1983) find in his review of studies on eyewitness testimony (EWT)?

  He noted contradictory findings regarding the effects of anxiety on arousal.
• What happens to a person psychologically and emotionally when they witness a crime?

  They experience emotional and psychological changes in their body, activating the fight or flight response.
• How does the level of arousal/anxiety affect recall accuracy according to the Yerkes-Dodson Law?

  Lower levels of arousal/anxiety lead to lower accuracy of recall, while accuracy increases with higher anxiety until an optimal level is reached.
• What is the optimal level of anxiety in relation to recall accuracy?

  The optimal level of anxiety produces maximum accuracy in recall.
• What occurs to recall accuracy if a person experiences anxiety beyond the optimal level?

  Recall accuracy drastically declines if anxiety exceeds the optimal level.
• what is a limitation to johnson's and scott's study?


  it may not have tested anxiety. Participants focusd on the weapon due to suprise rather than anxiety. Pickel (1998) conducted an experiment using scissors, a raw chicken leg, a wallet, and a handgun as hand-held items in hairdressing video (scissors are high anxiety, low unusualness). eyewitness accuracy was significantly lower in high unusualness conditions ( handgun and chicken leg). This suggets weapon focus effect is due to unusualness rather than anxiety/arousal, and therefore tells us little about effects of anxiety on EWT.
• what is a strength for negative effects on anxiety on EWT?


  Support

  Valentine and Mesout's study (2009) supports research on weapon focus effect, having negative effects on recall. The researchers used an objective measure (heart rate) of participants to divide them into high and low anxiety groups. The finding shown High levels of anxiety disrupted ability to recall details of actor in London's dungeon Labyrinth

  • suggests high levels of anxiety do have negative effects of recall on immediate eyewitness recall of a stressful event.
• what is a strenght of positive effects of anxiety on recall?


  Supporting evidence

  Christianson and Hubinette (1993) interviewed 58 actual witnesses of bank robbries in sweden. soem f the witnesses wre directly involved like bank workers, and some were indirectly involved like bystanders. Reseatchers assumed those directly involved were most anxious. Findings shown that recall was more than 75% accurate across all witnesses, and direct victims were even more accurate.

  • findings from actual crimes show that anxiety doesn't reduce accuracy of recall for eyewitnesses and may even enhance it.
• what is a counterpoint to the strength of positive effects of anxiety on recall?


  Christianson and Hubinette interviewed their participants after the event (4-15 months). Researchers therefore had no control over what happened before the interviewing time (e.g. post-event discussions). These effects of anxiety may have been overwhelmed by these other factors and impossible to assess by the time that they were interviewed. Therefore the lack of control over cofounding variables can be responsible for their findings, so invalidating their support.