Key Study: Loftus and Palmer (1974)

• Aim:

  To investigate how different leading questions would affect the overall outcome of the mean estimated speed for each group participant group
• Method:

  45 American students participated in this laboratory experiment.

  • IV = the verb used to describe the incident
  • DV = the estimated speed
• Procedure:

  • Elizabeth Loftus and John Palmer (1974) arranged for participants (students) to watch film clips or car accidents and then gave them questions about the accident
  • In the critical question (a leading question) participants were asked to describe how fast the car was travelling: 'About how fast were the cars going when they hit each other?'
  • It is a leading question - verb 'hit' suggests the speed that the car was going. 5 groups of participants each given a different verb in the critical question.
  • 'Hit', 'contacted', 'collided', 'bumped', 'smashed'
• Results:

  The mean estimated speed was calculated for each participant group. The verb 'contacted' resulted in a mean estimated speed of 31.8 mph. For the verb 'smashed' the mean was 40.5 mph
• Conclusion:

  The leading question biased the eyewitness recall of an event. Dependant on the verb used, there is a higher or lower mean estimated speed calculated, e.g. the verb 'contacted' compared to 'smashed'