Misleading Information affecting EWT

Loftus & Palmer (1974)
Aims
-Investigate accuracy of memory after witnessing a car accident - to see if leading questions distort accuracy of an eye-witness immediate recall


Procedure

  • 45 students (reduces population validity)
  • shown films of traffic accidents (lacks ecological validity - mundane realism)
  • questions after included a critical one about speed of the car containing the verb 'hit', 'smashed', 'collided', 'bumped' and 'contacted'

Findings

  • group with verb smashed estimated higher speed (41 m/h)
  • group with verb contacted estimated lowest speed (30 m/h)

Conclusions

  • leading questions (post-event info) can have a significant effect on memory (either on original memory or on recall)

Why do leading
questions affect EWT

response-bias explanation - know in experiment, know answer is wrong but gives answer that makes sense in the question
Suggests wording of question doesn't affect memory - but influences how they answer (demand characteristic - 'smashed' encourages them to choose a higher speed estimate

substitution explanation - wording of question actually changes the memory

Loftus & Palmer (1974) SECOND EXPERIMENT
Findings

  • tested a different set of participants after a week
  • those given 'smashed' were more likely to recollect broken glass (there was none)
  • supports substitution explanation

Conclusions

  • shows significant effect of post-event info on later recall of events &/or the way info is stored

Post-event Discussion

Gabbert et al (2003)

  • participants watched a video of the same crime but from different points of view
  • participants then discussed what they had seen then completed a test of recall
    Findings:
  • 71% of participants mistakenly recalled aspects of the event that they did not see compared to the 0% of a control group where there had been no discussion

Why does post-event discussion affect EWT

  • memory contamination - when witnesses discuss it with each other, their EWT may become altered/distorted
  • they combine (mis)information from other witnesses with their own memories
  • memory conformity - witnesses often go a long with each other - either to win social approval or because they believe the other witnesses and they are wrong
  • (unlike memory contamination) the actual memory is unchanged

EVALUATION OF FACTORS AFFECTING MISLEADING INFORMATION

!STRENGTH!

real-world application

  • has important, practical uses in criminal justice system
  • consequences of inaccurate EWT can be very serious
  • psychologists can be expert witnesses in court as they explain the limits of EWT

!LIMITATION!

  • Loftus & Palmer's participants watch films in a lab - very different experience from witnessing a real event
  • EWT may be more dependable than many studies suggest

!LIMITATION!

evidence against substitution

  • Sutherland & Hayne (2001) showed participants a video clip
  • when participants later asked misleading questions - recall was more accurate for central details than peripheral ones
  • suggests original memories for central details survived - not predicted by substitution explanation

!LIMITATION!

evidence challenging
memory conformity

  • Skagerberg & Wright (2008) showed participants film clips (2 versions - muggers hair dark brown in one and light brown in the other)
  • participants discussed clips in pairs - each having seen different versions
  • they often did not report what they had seen in the clips/what they heard from co-witnesses - but a blend of the 2
  • suggests memory itself is distorted rather than just conforming