8. Accuracy of eyewitness testimony: Anxiety

define anxiety

an unpleasant emotional state that is often accompanied by increased heart rate and rapid breathing

Loftus & Burns (1982)

pps were shown a violent version of a crime where a boy is shot in the face

pps had significantly impaired recall for events running up to the violent incident

suggests anxiety has a negative effect on EWT

Johnson and Scott (1976)

A: investigate whether weapon focus effect reduces the accuracy of EWT

P: made pps sit in a waiting room where they heard an argument in an adjoining room, and then saw a man run through the room carrying either a pen covered in grease (low-anxiety condition) or a knife covered in blood (high-anxiety condition). pps were then asked to identify the man from a set of photos.

F: mean accuracy was 49% in identifying the man in the low-anxiety condition compared to 33% in the high-anxiety condition

C: supports idea of weapon focus effect = the weapon in a criminal’s hand distracts attention, because of the anxiety it creates, and therefore reduces accuracy of identification

Christianson & Hubinette (1993)

A: investigate effect of anxiety on memory

P: questioned 58 real witnesses of a bank robbery in Sweden. witnesses were either victims or bystanders. the interviews were conducted 4-15 months after the robberies

F: all witnesses showed generally good memories for details of the robbery itself (over 75% recall). victims were more accurate in their recall compared to bystanders.

C: anxiety has a positive effect on accuracy of memory

Deffenbacher (1983)

reviewed 21 studies of the effects of anxiety on EWT = found that 10 of these studies had results that linked higher arousal levels to increased accuracy in EWT, while 11 studies showed the opposite

as we become moderately anxious, EWT accuracy improves. as we hit the peak of anxiety, accuracy decreases because of increased fatigue = Yerkes-Dodson effect

Yerkes-Dodson effect

up to a point, anxiety (arousal) improves performance, but after that point, it has a negative effect on performance

one limitation is weapon focus effect may not be caused by anxiety

Pickel (1998) proposed that reduced accuracy of identification could be due to surprise rather than anxiety. pps watched a thief enter a hairdressing salon carrying either scissors (high threat, low surprise), a handgun (high threat, high surprise), a wallet (low threat, low surprise), or a raw chicken (low threat, high surprise) = identification was least accurate in the high surprise conditions rather than high threat

suggests weapon focus effect is related to surprise rather than anxiety

one strength of research in the effect of anxiety on accuracy of memory is support from real life

Christianson and Hubinette (1993) was a study of a real life crime, which suggested that anxiety has a positive effect on memory

lab studies do not replicate the levels of anxiety experienced by a real eyewitness during an actual crime

Deffenbacher et al (2004) agreed with this but found (from a review of 34 studies) that lab studies in general demonstrate that anxiety leads to reduced accuracy, and that real-life studies are associated with an even greater loss in accuracy

these findings contradict those of Christianson and Hubinette (1993), but suggest that the results from lab studies are valid as they are supported by most real-life studies