Reaching A Verdict

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Persuading a Jury 1.1 Effect of Order Testimony


Aim: To find out if whether there is a primacy or recency effect in relation to witness testimony.

Method: They manupulated the order in which witnesses appreared and the order of testimony given by each. This included 192 undergraduate students who were all eligible for jury service. They had to read a 13 page transcript of a r*pe trial with 2 defendents. The study included 2 witness order conditions: Witness Guilty and Witness Innocent. Also there were 2 testimony conditions: Testimony Guilty and Testimony Innocent. Jurors were asked to make 2 kinds of judgments: 1) Whether they thought the defendent was guilty of r*pe, attempted r*pe or not guilty; 2) to indicate, on an 8-point scale ranging from 'not confident at all' to 'very confident', how confident they felt about their verdicts.


1) The greatest number of guilty verdicts occurred when the strongest 'guilty' witness and testimony came first.

2) Jurors were more confident of their guilty verdicts when they heard the 'guilty' witness and testimony first. 

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Persuading a Jury 1.2 Persuation


Aim: To investigate the influence that expert witnesses can have on jury decision making.

Method: the study was a lab experiment, using independent measures. A sample of 120 students from Washington, all eligible for jur service, volunteered for course credits. They were spilt into groups of 6 and given a booklet containing instructions, a description of a violent crime and a summary of the trial. Half of the groups also read an expert witness testimony outlining reasons why eyewitness could be inaccurate: Difficulties recognising members of another rcae, the negative effects of stress on memory recall or weapon focus. After this each group were asked for a verdict.


1) There was a much higher conviction rate in the 'no expert testimony' group (7) compared to the 'expert testimony' group (3).

2) The groups who heard the expert witness spent longer discussing eyewitness testimony (10 minutes) compared to the groups that didnt (7 minutes).  

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Persuading a Jury 1.3 Effect of Inadmissible Evide


Aim: To investigate the effect of instructions to disregard inadmissible evidence on jurors' judgments.

Method: 236 psychology students participated as part of their course requirement. They listened to a mock trial of a theft where a piece of critical evidence was introduced 'by accident'. In 4 different condtions the judge either ruled the evidence asmissible; ruled it inadmissible; ruled it inadmissible and gave a legal explanation as to why; or no critical evidence was presented (control). They then completed a questionnaire asking them to make a verdict. 


1) Admissible- 64%

2) Inadmissible with legal explanation- 55%

3) Inadmissible without legal explanation- 43%

4) Control- 42%

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Witness Appeal 2.1 Attractiveness of Defendant


Aim: To test the hypothesis that an attractive defendent is less likely to be seen as guilty.

Method: 145 psychology students took part in a lab experiment using a mock trial. They were asked to read a trial summary of a sexual harassment case and were shown photos of the defendent. Half were shown an attractive photo and the other half were shown an unattractive defendent and then were asked to decide whether the defendant was guilty or innocent. 


1) When the defendent was attractive, guilts verdicts were found 56% of the time compared to 76% for the unattractive defendent. 

2) Physical attractiveness does have an impact on the way a jury views defendents. 

3) The Halo Effect could cause this as our cognitive bias is influenced by our impressions of people, attractive people are seen as more likely to be honest, more important in society and more likely to have brighter futures. 

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Witness Appeal 2.2 Witness Confidence

Penrod and Cutler

Aim: To examine several factors that jurors might consider when evaluating eyewitness identification evidence, one is witness confidence.

Method: Participants, students and experienced jurors, were shown a mock trial of a robbery. One of the 10 IV's was confidence of the witness, who either said she was 80% or 100% confident that she had correctly identified the robber.


1) When the witness was 100% confident, the conviction rate was 67% compared to 60% when the witness was 80% confident.

2) The more confident the witness is, the more likely the jury are to believe them.

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Witness Appeal 2.3 Effect of Shields and Videotape

Ross et al. 

Aim: To find out if the use of protective shields and videotaped testimonies increase the likelihood of a guilty verdict. They also investigated whether the use of shields affects the credibility of the witness or defendant. 

Method: 300 psychology students watched a videotaped trial. 3 versions were created; 1st- the child was in full view, 2nd- the child was behind a screen, 3rd- child gave evidence via video link. 


1) There was no significant difference between the 3 conditions when giving their verdicts.

2) 58.6% of femals found the defendent guilty, compared to jsut 38.6% of males. 

3) There was no significant difference across the 3 condtions for credibility.

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Reaching A Verdict 3.1 Stages in Jury decision mak

Hastie et al.

They suggest that jury discussion goes through the following 3 stages:

1) Orientation Period- relaxed and open discussions, set the agenda, raise questions and explore facts and different opinions arise.

2) Open Confrontation- Fierce debate, focus on detail, explore different interpretations, pressure on the minority to conform and support for the group decision is established.

3) Reconciliation- Attempts to smooth over conflicts, tension is released through humour and then a decision is made. 

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Reaching A Verdict 3.2 Majority Influence


Aim: To investigate the extent to which social pressure from a majority group could influence a person to conform. 

Method: 123 participants took part in a lab experiment using a line judgement task. Asch put only 1 participant in a room with 7 confederates, each person had to state aloud which comparison line was most like the target line. The real participant sat at the end of the row and gave their answer last. In 12 out of 18 trials, the 7 confederates gave the wrong answer. 


1) About 1/3 (37%) of participants conformed with the majority and gave the wrong answer. 

2) It shows a strong tendency to conform to group pressure.

3) People confrom for 2 reasons; normative influence and informational influence.

Asch's study is not about jury decision making but the findings can be applied to jury decision making 

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Reaching A Verdict 3.2 Minority Influence


Aim: to see whether a consistent minority of participants could influence a majority to give an incorrect answer in a simple colour perception test. 

Method: 172 females were placed in groups of 6 (4 real, 2 confederates). They were shown 36 slides, which were different shades of blue, and asked to state the colour of each slide out loud. In the 1st condition the confederates were consistent and answered green for all slides. In the 2nd condition they were inconsistent and answered green 24 times and blue 12 times. There was a control group with no condederates.


1) In the control group, 0.25% answered green.

2) In the inconsistent condition, 1.25% answered green.

3) In the consistent condtion, 8.42% answered green 

Not about jury decision making but can be applied to it.

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