Eyewitness Testimony

• what is eyewitness testimony?

  evidence give in court or a police investigation by someone who has witnessed a crime or accident
• aim of loftus and palmer (1974) - leading questions

  to investigate the effect of leading questions on the accuracy of eyewitness testimony
• method of loftus and palmer (1974) - leading questions

  • 45 American students divided into five groups
  • all participants watched a video of a car crash and were then asked a specific question about the speed of the cars
  • loftus and palmer manipulated the verb used in the question e.g. smashed/collided/bumped
• results of loftus and palmer (1974) - leading questions

  • smashed - 40.5 mph
  • contacted - 31.8 mph
  • 32% who were previously questioned using the verb smashed reported seeing broken glass
  • 14% of participants who were previously questioned using the verb hit reported seeing broken glass
• strength of loftus and plamer (1974)

  • research took place in a university laboratory and was therefore highly controlled. This high degree of control reduces the chance of extraneous variables, increasing the validity of the results. Furthermore, it is easy for psychologists to replicate their research, to see if the same results are achieved with a different population.
• limitations of loftus and palmer (1974) (1)

  • questionable ecological validity. Questioning participants about everyday events like a car crash appears to be a genuine measure of eyewitness testimony. However, the participants watched a video of a car crash. In everyday reports of car accidents, witnesses rarely see the whole event; they are either involved in the event directly, or see a small part of the event. Results do not reflect everyday car accidents and we are unable to conclude if eyewitnesses to real accidents, would be susceptible to leading questions in the same way.
• limitations of loftus and palmer (1974) (2)

  • lacks population validity. Their two experiments consisted of 45 and 150 students from the University of Washington. It is reasonable to argue that the students in their experiment were less experienced drivers, who may be less accurate at estimating speeds. Consequently, we are unable to generalise the results to other populations, for example, older and more experienced drivers, who may be more accurate in their judgement of speeds and therefore not as susceptible to leading questions.
• aim of gabbert et al (2003) - post-event discussion

  investigate the effect of post-event discussion on the accuracy of eyewitness testimony
• method of gabbert et al (2003) - post-event discussion

  • 60 students from university of Aberdeen and 60 older adults
  • Participants watched a video of a girl stealing money from a wallet.
  • The participants in the co‐witness group were told that they had watched the same video; however, they had in fact seen different perspectives of the same crime and only one person had actually witnessed the girl stealing.
  • Participants in the co‐witness group discussed the crime together.
  • All of the participants then completed a questionnaire, testing their memory of the event.
• results of gabbert et al (2003) - post-event discussion

  • 71% in co-witness group recalled information they had not actually seen
  • 60% said that the girl was guilt, despite the fact that they had not seen her commit a crime
• strength of gabbert et al (2003)

  • Gabbert et al. tested two different populations, university students and older adults, and found little difference between these two conditions. Therefore, her results provide good population validity and allow us to conclude that post‐event discussion affects younger and older adults in a similar way.
• limitations of gabbert et al (2003) (1)

  • questionable ecological validity. The participants in the co‐witness condition witnessed different perspectives of the same crime, as would typically be the case in real‐life crimes. However, as in Loftus and Palmer’s research, these witnesses knew they were taking part in an experiment and were more likely to have paid close attention to the details of the video clip. Therefore, these results do not reflect everyday examples of crime, where witnesses may be exposed to less information.
• limitations of gabbert et al (2003) (2)

  • we are unable to conclude why the distortion occurs. The distortion could be the result of poor memory, where people assimilate new information into their own accounts of the event and are unable to distinguish between what they have seen and what they have heard. On the other hand, it could be that the distortion occurs due to conformity and the social pressure from the co‐witness. Further research is required to answer this question.
• method of johnson and scott (1976)

  • The experiment used an independent groups design, as participants were then exposed to one of two conditions: 1) ‘no‐weapon’ condition. an individual left the laboratory and walked past the participant holding a pen, with his hands covered in grease. 2) ‘weapon’ condition, an individual (the target) running into the reception area, holding a bloodied letter‐opening knife.
  • Both groups were then asked to identify the person who had left the laboratory.
  • The participants were informed that the suspect may, or may not, be present in the photographs.
• results of johnson and scott (1976)

  • 'no weapon' - correctly identified the man 49% of the time
  • 'weapon' - correctly identified the man 33% of the time
• limitations of johnson and scott (1976)

  • lacking ecological validity. Although the participants were waiting in the reception area outside the laboratory, they may have anticipated that something was going to happen, which could have affected the accuracy of their judgements. Furthermore, the results from real‐life case studies (see above) refute the findings of Loftus and suggest that her results do not represent real‐life cases of extreme anxiety.
• limitations of johnson and scott (1976)

  • numerous ethical guidelines were broken. The participants were deceived about the nature of the experiment and not protected from harm. Loftus (Johnson & Scott) exposed some of the participants to a man holding a bloodied knife, which could have caused extreme feelings of anxiety. This is an issue, as these participants may have left the experiment feeling exceptionally stressed and anxious, especially if they, or someone they knew, had been involved in a knife crime.
• method of yuille and cutshall (1986)

  • 13 witnesses, aged between 15 and 32, agreed to take part in a follow-up interview after witnessing a real-life shooting
• results of yuille and cutshall (1986)

  • found the 13 witnesses who took part in the follow-up interview were accurste in their eyewitness accounts five months later
• limitations of factors affecting eyewitness testimony

  • Loftus & Palmer’s (1974) research is an example of experimental reductionism: the complex process of memory after a film of what would in real‐life be a traumatic event is reduced to the effect of the wording of a leading question (IV) on the eyewitness memory (DV). The research also suffers from cultural bias, as samples of participants were from either Britain or America
  • all use a nomothetic approach to try to establish universal laws regarding eyewitness testimony, but their claims are based on small, non- representative samples.