A2 Psychology: Unit G543 Options in Applied Psychology Option: Forensic Psychology Topic: Reaching a Verdict Persuading a Jury Issue: Persuading a Jury

Unit G543: Options in Applied Psychology Health & Clinical Psychology –Stress Causes of stress Measurement of stress Management of stress –Dysfunctional Behaviour Diagnosis of dysfunctional behaviour Explanations for dysfunctional behaviour Treatment for dysfunctional behaviour Forensic Psychology –Making a Case Interviewing witnesses Interviewing suspects Creating a profile –Reaching a verdict Persuading a juryPersuading a jury Witness appeal Reaching a verdict

Persuading a Jury: effect of order on testimony Should counsel present their case as a story unfolding in chronological order? Should they use the benefit of the primacy-recency effect to present their best witnesses first or last? –Would this disrupt the order of events in the jurors mind?

Persuading a Jury: Pennington & Hastie Title Effects of memory structure on judgementAim 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

Persuading a Jury: Pennington & Hastie Methodology A laboratory experiment The 2 nd of two reported in this studyParticipants 130 students from Northwestern University and Chicago University Paid for taking part in a one-hour experiment Allocated to one of 4 conditions –Roughly equal numbers

Persuading a Jury: Pennington & Hastie Procedure Participants listened to a tape recording of the stimulus trial (Mass vs Johnson) and then responded to written questions Told to reach either a guilty or not guilty verdict on a murder charge 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

Persuading a Jury: Pennington & Hastie Procedure continued In the story-order condition, evidence was arranged in its natural order In the witness order condition, evidence items were arranged in the 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 In all cases, the stimulus trial began with the indictment and followed the normal procedure, ending with the judges instructions

The 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

% of participants choosing a verdict of guilty of murder by prosecution and defence order conditions Defence evidence story order Defence evidence witness order mean Prosecution evidence story order Prosecution evidence witness order mean457058

Persuading a Jury: Pennington & Hastie Results The table shows that story order persuaded more jurors to vote guilty in favour of 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 story order, the guilty rate drops to 31%

Persuading a Jury: Pennington & Hastie Results continued As predicted, the greatest confidence in their verdict was expressed by those who heard the defence or prosecution in story order Least confidence was expressed by those who heard the two-witness order conditions

Persuading a Jury: Pennington & Hastie Discussion Because the primacy and recency effects were controlled for, Pennington & Hastie are confident that they have shown the persuasive effect of presenting information in story order In this case there is a difference in the defence case, which seems not to be as persuasive as the prosecution case, even when presented as a story –Pennington & Hastie suggest the defence case in the original trial was not as plausible The victim was drunk and lunged forward onto his assailant’s knife