Pennington and Hastie

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  • Created by: Steff06
  • Created on: 01-05-16 16:16
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  • Pennington and Hastie
    • Aims:
      • To investigate whether or not story evidence summaries are true causes of the final verdict decisions and the extent to which story order affects confidence in those decisions.
    • Methodology:
      • A laboratory experiment. The second of 2.
    • Participants:
      • 130 students from Northwestern University and Chicago University.
      • Paid for participation in an hour-long experiment. They were allocated to 1 of 4 conditions in roughly equal numbers.
    • Procedure:
      • Participants listened to a tape recording of the stimulus trial and then responded to written questions.
      • They were told to reach either a guilty or not guilty verdict on a murder charge and than asked to rate their confidence in their own decision on a 5-point scale.
      • They were separated by partitions and did not interact with each other. In the story order condition, evidence was arranged in its natural order.
      • In the witness-order condition, evidence items were arranged in the order closest to the original trial.
      • The defence items comprised 39 not-guilty pieces of evidence and the prosecution items, 39 guilty pieces of evidence from the original case.
      • Conditions: 39 prosecution items in story order, 39 defence items in story order, 39 prosecution items in witness order, 39 defence items in witness order.
      • In all cases, the stimulus trial began with the indictment and followed the normal procedure, ending with judge's instructions.
    • Results:
      • Story order persuaded more jurors of Caldwell's guilt in the prosecution case. If the defence presented its evidence in witness order, even more jurors would find a guilty verdict.
      • If the positions were reversed and the defence had the benefit of the story order, the guilty rate drops to 31%. Greatest confidence in their verdict was expressed by those who heard the defence or prosecution in story order.
        • Least confidence expressed by those who heard the 2 witness-order conditions. Confident shown persuasive effect of presenting info in story order.
          • Difference in defence case due to case itself where defence case is less plausible as victim was drunk and lunged onto assailant's knife.


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