Eyewitness Testimony Flashcards
Eyewitness testimony (EWT)
Evidence provided by people who witnessed a particular event/crime
* relies on recall from memory
* includes descriptions of crime scene/ criminals
General factors affecting EWT
- racial stereotypes
- cultural expectations
- interference (too much information)
- gender
- age
- trauma/shock - distorts memory
- environmental factors
- fear/anxiety
3 main factors affecting EWT
- Misleading information (leading questions)
- Post-event discussion
- Anxiety
Misleading information (leading questions)
Leading question- a question that leads to a certain answer because of the way it was phrased
* e.g. you like… dont you?
* Loftus + Palmer
Loftus + Palmer
- investigated misleading questions
- 1974
- invited ppts to lab experiment
- all shown video of car crash
- 5 conditions (each asked a question with different verb)
- e.g how fast were the cars going when they hit/contacted/bumped/collided/smashed into each other
- RESULTS: groups who were asked ‘smashed’ estimated the speed of 40.5mph, ‘collided’=39.3mph, ‘bumped’= 38.1, ‘hit’=34.0 and ‘contacted’ had the least 31.8 mph
- leading questions affect memory by using ambitious words like smacked in comparison to contacted
- in second part of study ppts were asked if they had seen broken glass (there was none)
- Ppts who heard ‘smashed’ were more likely to report broken glass
Evaluation: Loftus + Palmer
+/- Loftus used a lab experiment which controlled extaneous variables but artificial tasks such as recall arent applicable to everyday life. Therfore its low in ecological validity
- Sample used university students who may lack experience in driving + therefore may have guessed speed of collision. Some ppts may have also demonstated demand characteristics by guessing the aims of study
- Small smaple size of 45 ppts, so study isnt representative of wider population (low in population validity)
+ Raised awareness of how memory can be distorted by misleading questions
Post-event discussion
Occurs when there more than 1 witness to an event
* witnesses may discuss what they have seen with co-witnesses
* this may influence the accuracy of recall of the event
* Gabbert et al
Gabbert et al
- investigated post event discussion
- 2003
- each ppt watched a video of the same crime but form different points of view- so each ppt could see elements in the film that the other could not
- ppts then discussed in pairs what they’d seen before individually completing a recall test
- RESULTS: 71% of ppts mistakenly recalled aspects of the event that did not see in the video but had picked up in discussion (figure was 0% for control group)
- Gabbert concluded that witnesses often go along with each other either to win social approval/ because they believe the other witnesses are right and they are wrong- ‘memory conformity’
Evaluation: Gabbert et al
- Task lacks ecological validity because the ppts are watching a video rather than experiencing it real life
- There’s a risk of demand charactistics because its lab experiment. By being ‘set-up’ its easyfor ppts to guess the aim of study
Anxiety
theory- Yerkes Dodson inverted U-law
* Graph shows performance (accuracy of EWT) increases with physiological/mental arousal, but only up to a certain point:
1. When levels of arousal become too high, performance decreases
2. some levels of anxiety is good (optimum) but when anxiety levels reach above the optimal level, accuracy of EWT is reduced
* Johnson + Scott study
* Yullie + Cutshall study
* Christianson et al
Johnson + Scott
- investigated anxiety
- 1976
- ppts were asked to sit in a waiting room, they heard an arguement in the next room
- Condition 1- saw a man walk out of the room with a pen in his hands
- Condition 2- saw a man walk out of the room holding a knife covered in blood
- ppts were asked to identify the man from a set of pictures
- correct identification of man hoding pen = 49%
- correct identification of man holding knife = 39%
- Anxiety reduced the accuracy of memory because ppts focused more on weapon rather than criminal - weapons focused effect
- Tunnel theory- witness focuses on weapon because its a source of anxiety
Evaluation: Johnson and Scott
- Ethical issues- study failed to protect ppts from psychological harm. Seeing a person covered in blood with a knife might have been traumatic so creating anxiety raises ethical issues
- Pickel (1998) conducted an experiment usinng scissors, a handgun, a wallet or raw chicken in a hair salon. EWT was significantly inaccurate in conditions involving a chicken and handgun. Suggests that the weapons focus effect is due to the unusualness/ surprise at what they see rather than the anxiety
- Due to lab experiment conditions of the study theres a risk of demand characteristics
- supports Yerkes U law- when arousal levels increased, ppts were less likely to remember suspect
Yullie and Cutshall
- investigated anxiety
- 1986
- study of a real life shooting in a gun shop in Canada
- 13 witnesses interviewed 4-5 months after incident and these were compared original police interview at the time
- Ppts were also asked to rate how stressed they were at time of incident
- found that witnesses were very accurate in their account. those ppts who reported the highest levels of stress were most accurate
- goes against the idea that anxiety reduces the accuracy of memory
Evaluation: Yullie + Cutshall
- Low in reliablity- one-off unique case study cant replicated
- Low in control over extraneous variables- things could have occured during the 4-5 month period e.g media influence
+ High in ecological validity, field experiment as it actually happened - Goes against Yerkes U-law- ppts had high recall accuracy
Christianson et al
- invetigated anxiety
- questioned 110 ppl who had witnessed genuine bank robberies
- some of them had been bystanders in the bank (low anxiety group) and others had been directly threatend by robbers (high anxiety group)
- ppts were asked to recall as many details as they could about the incident
- ppts who had been subjected to the greatest anxiety showed more detailed and accurate recall than the bystanders
