Persuading a Jury - Pennington and Hastie
Aim: To understand if story order is superior in gaining a conviction and the extent to which story order effects confidence in those decisions.
Method: Lab experiment set up as a mock trial.
Participants: 130 students that were paid to participate.
Procedure: Jurors listened to a tape recording of a stimulus trial which was based on a real case. They responded to written questions and had to reach a verdict on guilty or not guilty. They also had to rate their confidence on their decision. Information was either presented in story order, or witness order
Results: Story order was significantly more effective than witness order and more jurors expressed higher confidence levels with the defence and prosecution in story order.
Conclusion: The order in which evidence is presented has an effect on jurors decision making abilities and story order has more of a persuasive effect.
Persuading a Jury - Cutler
Aim: To investigate whether the presence of an expert witness would affect the juror's decision making ability.
Method: Lab experiment using a videotaped mock trial of a robbery.
Sample: 538 undergraduates.
Procedure: Participants were shown a videotape of a robbery. Afterwards they individually completed a questionnaire and asked to give a verdict. They were asked how confident they were. There were four Independent variables:
- Witness Identifying Conditions (WIC): In the good condition there was no gun, no disguise a 2 day delay in identification) or the poor condition (handgun present, disguise and 14 day delay in identification)
- Witness confidence: In the good condition, witness claimed to be 100% confident whereas in the poor condition, only 80% that they identified the witness correctly.
- Expert Opinion Expressed: In half the trials, the expert witness would rate the eyewitness on a scale of 0-25. Low ratings were given to the poor WIC conditions and high ratings to the good WIC.
- Form of Expert Testimony: In the descriptive description, the expert psychologist used ordinary language to describe how different things affected memory; whereas in the confusing condition, lots of statistics were used and psychological language.
Results: Jurors gave more guilty verdicts when WIC's were good which increased if the psychologist used ordinary language. Jurors also expressed more confidence when the witness was 100% sure.
Conclusion: Expert testimony improved jurors knowledge of factors that might affect the accuracy of eyewitness testimony and made them pay more attention to WIC.
Persuading a Jury - Pickel
Aim: To investigate the role of the judge's instructions when followed by legal explanation.
Sample: 236 undergraduate students.
Procedure: Both groups listened to an audio tape mock trial where critical evidence was introduced 'accidentally' by a witness, this was objected to and the judge ruled it inadmissible and should not listen to it. One group was given a legal explanation of why the evidence was inadmissible and the other was just told to disregard the information with no explanation. Participants were then told to decide on a verdict.
Results: Mock jurors who were given no legal explanation to why the evidence was inadmissible were able to ignore it and found the defendant guilty whereas those that were given a legal explanation where unable to ignore it and found the defendant not guilty.
Conclusion: Calling attention to inadmissible evidence makes it more important to the jury and they pay more attention. By giving a legal explanation, it seems that the jurors tended to over-compensate and tended to give a not guilty verdict.
Witness Appeal - Castellow
Aim: To test the hypothesis that an attractive defendant is less likely to be seen as guilty and the more attractive the victim the more likely the guilty verdict.
Method: Lab experiment mock trial.
Sample: 71 males and 74 female psychology students given extra credits.
Procedure: Participants were given a photographs of defendants and victims in previous sexual harassment cases which were previously categorized on a scale of 1-9 (1 being unattractive)They were then asked if the defendant was guilty and asked to rate the defendant and victim on several bipolar scales such as dull-exciting, cold-warm, nervous-calm.
Results: Physically attractive defendants and victims were rates positively for other personality variables.Unattractive defendants were found guilty 76% of the time compared to 56% for attractive defendants.
Conclusion: Attractiveness does indeed have a powerful effect on jury judgement
Witness Appeal - Penrod and Cutler
Aim: To examine several factors, including confidence that jurors might consider when evaluating eyewitness identification evidence.
Method: An experiment using a mock trial scenario.
Procedure: Participants were shown a videotaped mock trial of a robbery. There were 10 independent variables which were manipulated, one of which was witness confidence. Eyewitness identification was key to the trial; the witness testified that she was either 80% or 100% confident that she had correctly identified the robber.
Results: The more confident the witness was of correctly identifying the suspect the more likely the jury were to believe them.
Conclusion:Witness confident plays a role in jurors believing them.
Witness Appeal - Ross
Aim: To find out if the use of protective shields and videotaped testimony increases the likelihood of a guilty verdict.
Method: Mock trial based on a court transcript.
Sample: 300 psychology students, 100 in each condition.
Procedure: Three versions of the transcript were filmed with actors playing the roles, one in the videotaped condition, shield condition and open evidence in court. The child actor would give evidence in court and the overall court procedure lasted for 2 hours. This involved the father (alleged sexual offender), the mother, two expert witnesses( one for defence and prosecution) and the child herself. The judge read a warning before the use of screen or video tape directing the jury not to imply guilt by their use. The participants were asked for their verdicts.
Results: There was no significant difference in guilty verdicts across the three groups, however there was a significantly higher tendency for females to find the defendant guilty.
Conclusion: This study shows that when a judges warning is given there are no disadvantages to the defendant in the use of shields and videotapes
Reaching a Verdict - Hastie
The three main staged they propose are as follow:
- Orientation Period: Setting of the agenda, relaxed and open discussion and airing of different opinions.
- Open Confrontation Period: Fierce debate, focus on the details of the crime, exploring different interpretations, pressure on the minority to conform and establishing of support for the group decision.
- Reconciliation Period: Once a decision is reached, there is an attempt to smooth over the conflicts that emerged during the confrontation period
Reaching a Verdict - Asch
Aim: To investigate the extent to which social pressure from a majority group could affect a person to conform
Method: Lab experiment
Procedure: Asch arranged for a naive participant to be asked a question to which several stooges of the experimenter had already given clearly the wrong answer. ('Which of three lines, A, B or C matches the stimulus line X?') He was interested to see if even in a crystal-clear decision, an individual would defer to the majority.
Results: Asch measured the number of times each participant conformed to the majority view. On average, about 1/3 of the participants who were placed in this situation went along and conformed with the clearly incorrect majority on the critical trials.
Conclusions: People conform for two main reaons: because they want to fit in with the group (normative influence) and because they believe the group is better informed than they are (informational influence)
Reaching a Verdict - Moscovici
Aim:To examine minority influence. In particular, to compare the impact of a consistent minority and an inconsistent minority on the views of the majority.
Method: Experimental method
Procedure: Participants were given eye tests to make sure they were not colour blind and then placed in groups of 6,4,2 confederates.They were shown 36 slides of different shades of blue and asked to state the colour out loud.Participants were told that the experiment was about colour perception.In the first part of the experiment, confederates were consistent and answered green for each of the slides.In the second part of the experiment, they were inconsistent and answered green 24 times and blue 12 times.There was also a control group with no confederates.
Results: The minority can influence the majority and this is much more effective when the minority are consistent.
Conclusion: Consistency is vital for minority influence to occur. If the minority consistently give the same answer they are more likely to sway a majority.