Factors affecting eyewitness testimony: anxiety

what is anxiety?

• a state of emotional and physical arousal

• The emotions include having worried thoughts and feelings of tension and physical changes include an increased heart rate and sweatiness

• Anxiety is a normal reaction to stressful situations but can affect the accuracy and detail of eyewitness testimony

Who conducted a study on how anxiety has a negative effect on recall?

Johnson and Scott (1976)

How does anxiety has a negative effect on recall?

anxiety creates physiological arousal in the body which prevents us from paying attention to important cues and so recall is worse

What was the procedure of Johnson and Scott’s study on how anxiety had a negative effect on recall?

• they let participants to believe they were going to take part in a lab study- while seated in a waiting room participants heard an argument in the next room

• In the ‘low-anxiety’ condition a man walking through the waiting area carrying a pen with grease on his hands

• In the ‘high-anxiety’ condition participants overheard the same seated argument but this time accompanied but the sound of breaking glass and a man walked out of the room holding a paper knife covered in blood

What were the findings of Johnson and Scott’s study on how anxiety had a negative effect on recall?

• the participants later picked out the man from a set of 50 photos; 49% of the participants who had seen the man carrying the pen were able to correctly identify him

• The corresponding figure for the participants that had seen the bloody knife was 33%

• the tunnel theory of memory- a witness’s attention narrows to focus on a weapon because it is a source of anxiety

Who conducted a study on how anxiety has a positive effect on recall?

Yuille and Cutshall (1986)

How does anxiety has a positive effect on recall?

• the stress of witnessing a crime or accident creates anxiety through physiological arousal in the body

• The fight or flight response is triggered which increases our alertness and improves our memory for the event as we become more aware of cues in the situation

What was the procedure of Yuille and Cutshall’s study on how anxiety has a positive effect on recall?

• conducted a study of a real-life shooting in a gun shop in Vancouver, Canada- the shop owner shot a thief dead

• There were 21 witnesses- 13 agreed to take part in the study

• The interviews were held 4-5 months after the incident and these were compared with the original police interviews made at the time of the shooting- accuracy was determined by the number of details reported in each account

• The witnesses were also asked to rate how stressed they were at the time of the incident, using a 7-point scale and asked if they had any emotional problems since the event, ie- sleeplessness

What were the findings of Yuille and Cutshall’s study on how anxiety has a positive effect on recall?

• the witnesses were very accurate in their accounts and there was little change in the amount of accuracy after 5 months- some details were less accurate though, ie- recollection of the colour of items, height/age/weight estimates

• Those participants who reporter high levels of stress were most accurate (about 88% compared to 75% for the less stressed group)

What is the Yerkes-Dodson law?

• lower levels of anxiety produce lower levels of recall accuracy

• Memory becomes more accurate as the level of anxiety experienced increases

• At a certain level the optimum level of anxiety is reached- point of maximum accuracy

• If an eyewitness experiences any more stress than this then their recall of the event suffers a drastic decline

What is a study that supports the yerkes-Dodson law?

• one problem with many lab-based and real-life is that they only compare high anxiety with low anxiety groups- inverted u theory cant be properly tested unless there is a moderate anxiety group as well

• Parker et al. (2006) overcame this problem by interviewing people who had been affected by the destruction of hurricane Andrew in US (1992)

• The researchers defined anxiety in terms of the amount of damage the participants suffered to their homes

• The researchers found that there was a link between the level of recall and the amount of damage/anxiety experienced

What study did Valentine and Mesout conduct?

• carried out a study in the real-life setting of the Horror labyrinth at the London dungeon- designed to be frightening with many scares (darkness, screams, gory models, sudden movements)

• Visitors to the labyrinth were offered a reduced entrance fee if they completed a questionnaire after their visit to report their anxiety levels- wore wireless heart monitors to confirm they were experiencing anxiety- participants were divided into high anxiety and low anxiety groups

• Participant task- describe a person encountered in the labyrinth (actor) and researchers found that high anxiety participants recalled fewest correct details of the actor and made more mistakes

• Also found that 17% of high anxiety group correctly identified actor in a line-up compared to 75% correct identification by those in low anxiety group.

evaluation- weapon focus effect may not be relevant

• the study by Johnson and Scott on the weapon focus may test surprise rather than anxiety- the reason participants focus on the weapon may be because they’re surprised at what they see rather than because they’re scared

• a researcher conducted an experiment using scissors, a handgun, a wallet or a raw chicken as the hand-held items in a hairdressing salon video (where scissors would be low anxiety, low unusualness)- eyewitness accuracy was significantly poorer in the high unusualness conditions (chicken and handgun)

• this suggests that the weapon focus effect is due to unusualness rather than anxiety/threat and so tells us nothing specifically about the effects of anxiety on EWT

evaluation- field studies sometimes lack control

• researchers usually interview real-life eyewitnesses sometime after the event- all sorts of things will have happened to the participants in the meantime that the researchers have no control over- discussions with other people about the event, accounts they may have read or seen in the media, the effects of being interviewed by the police, etc (ie- post event discussion)

• limitation of field research as it’s possible that these extraneous variables may be responsible for the accuracy of recall

• the effects of anxiety may be overwhelmed by these other factors, and impossible to assess by the time the participants are interviewed

evaluation- ethical issues

• creating anxiety in participants is very risky- it’s potentially unethical as it may subject people to psychological harm purely for the purposes of research

• this is why real-life studies are so beneficial- psychologists interview people who have already witnessed a real-life event, so there’s no need to create it

• this issue doesn’t challenge the findings from studies like Johnson and Scott but it does question the need for such research

• one reason is to compare findings with the less controlled field studies- and the benefits of this research may outweigh the issues

evaluation- demand characteristics operate in lab studies of anxiety

• most lab studies show participants a filmed (and usually staged) crime- most of these participants will be aware that they’re watching a filmed crime for a reason to do with the study

• chances are most of them will work out for themselves that they’re going to be asked questions about what they’ve seen