Loftus & Palmer - Misleading Qs

• Loftus and Palmer (1974)

  Conducted a classic experiment to investigate the effect of leading questions on the accuracy of eyewitness testimony
• Sample

  • 45 American students, divided into five groups of nine
• Experiment procedure


  1. Participants watched a video of a car crash

  2. Asked a specific question about the speed of the cars

  3. Loftus and Palmer manipulated the verb used in the question
• Verb used in the question

  Affected the estimated speed
• Verbs used

  • smashed
  • collided
  • bumped
  • hit
  • contacted
• Participants who were given the verb "smashed" reported an average speed of 40.5 mph, while those given "contacted" reported 31.8 mph, a difference of 8.7 mph
• The results show that the accuracy of eyewitness testimony is affected by leading questions and a single word in a question can significantly affect the accuracy of judgements
• Second experiment


  • 150 American students, divided into three groups
  • Watched a one-minute video of a car accident
  • Given a questionnaire to complete
• Questionnaire


  1. One group asked "How fast were the cars going when they smashed into each other?"

  2. Another group asked "How fast were the cards going when they hit each other?"

  3. Control group not asked about speed
• Verb used in the question

  Affected the likelihood of participants reporting seeing broken glass (which was not actually present)
• 32% of "smashed" group reported seeing broken glass, 14% of "hit" group, and 12% of control group