Eyewitness Tesimony

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  • Created by: Amy
  • Created on: 04-01-13 12:39

Misleading questions: Loftus and Palmer (1974)

- Asked participants about the speed of two cars in a crash using misleading questions to see if it effected their recall

- When asking "how fast were the cars when they smashed?" participants said the car travelled at approx. 40 mph

-When asking "how fast were the cars when they contacted each other?" participants said the car travelled at approx. 30 mph 

Evaluation 

- Lacks mundane realism: used video tapes 
- Lacks ecological validity: only asked students 
- Responce bias: participants many not have been sure about the speed of the car to start with but just gave an answer to fit the expectations of the researcher

+High internal validity  

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Anxiety

Anxiety is an unpleasant emotional state where we fear that somthing bad will happen. Adrenalin = Anxiety 

Christianson and Hubinette:

  • interviewed 58 real witnesses to a bank robbery. Those that were threatened were more accurate and remembered more details in their recall
  • High in ecological validity and supports Mcgoughs rat study.

Meta-analysis (2004) contrasting evidence:

  • 18 studies on the relationship between eyewitness recall and anxiety. high levels of stress affect the accuracy of recall negatively.
  • High in validity and reliabilty 

Yerkes Dondson Law:

  • performance improves with increases in anxiety up to an opitmal point. Low and High amounts affects recall negatively therefore eyewitness needs reasonable levels of anxiety
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Weapon Focus

Loftus et al: 

  • participants heard a heated argument in a room next door and were then put under one of two conditions: 
    1. man emerged with a pen and grease on his hands
    2. man emerged with a knife and blood on his hands 
  • Participants were asked to identify the man from 50 photos:
    1. = 49% accurate
    2. = 33% accurate 
  • Weapon focus distracts attention from the person holding it and therfore mean eyewitness has poor recalls for violent crimes 

+controlled variable so valid
+ Reliable (Lab experiment)

- decieved participants/ didn't get informed consent 
- weapon may have caused psychological harm 

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Age

comparison of primary school children and college students:

  • PSC had a higher rate of identifying someone than the CS due to demand characteristics. college students had a sense of justice
  • However PSC were more likely to make more errore of identification 

Witnesses to an incident:

  • 35 mins after there was no difference between the recall of 16-33 year olds and 60-82 year olds
  • 1 week after the incident older witnesses were significantly less accurate 

Anastasi and Rhodes:

  • participants of three different age groups where shown 24 different photographs representing the age groups.
  • participants are better at recognising people of your own age group and ethinic group 
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