Accuracy of eyewitness testimony- Misleading information (7)

• What was the aim of Experiment 1?

  To investigate whether phrasing of a question can influence speed judgement
• How many participants were involved in Experiment 1?

  45 students
• What was the method and design used in Experiment 1?

  Laboratory, independent group design
• What was the dependent variable in Experiment 1?

  Estimated speed of cars in miles per hour
• What was the independent variable in Experiment 1?

  Verb used in question (hit/smashed/collided/bumped/contacted)
• What was the aim of Experiment 2?

  To investigate whether phrasing of a question can influence speed judgement
• How many participants were involved in Experiment 2?

  150 students
• What was the method and design used in Experiment 2?

  Laboratory, independent group design
• What were the dependent variables in Experiment 2?

  Recollection of broken glass, speed estimate
• What was the independent variable in Experiment 2?

  Verb used in question (smashed/hit/none)
• What was the procedure for Experiment 1?

  Seven films were shown, followed by a questionnaire with a critical question about speed.
• What was the critical question in Experiment 1?

  ‘About how fast were the cars going when they hit each other?’
• How were the verbs changed in the critical question of Experiment 1?

  Hit was changed to smashed/collided/bumped/contacted.
• What were the controls in Experiment 1?

  Same films shown, identical questions except for the independent variable, random placement of critical question.
• What were the results regarding estimated speed for the verb 'smashed' in Experiment 1?

  The estimated speed was 40.5 mph.
• What was the conclusion of Experiment 1?

  The form of the question could significantly alter the witness’ answer.
• What are the two pieces of information that memory consists of according to the conclusions?

  Information gained at the moment of the event and information gained after the event.
• How does the severity of the verb 'smashed' affect memory of the event?

  It distorts memory of the event, making it seem more severe.
• What are the key findings from the results of Experiment 1 regarding estimated speeds?

  • Smashed: 40.5 mph
  • Collided: 39.3 mph
  • Bumped: 48.1 mph
  • Hit: 34 mph
  • Contacted: 31.8 mph
• What are the key findings from the results of Experiment 2 regarding recollection of broken glass?

  • Smashed: YES: 16, NO: 34
  • Hit: YES: 7, NO: 43
  • Control group: YES: 6, NO: 44
• What are the two types of biases identified in the conclusions of the experiments?

  1. Response bias - uncertain participants use verb to bias response
  2. Change in memory - verb affects perception of event severity