Criminological psychology (option): factors influencing jury decision-making

Defendant characteristics

• Attractiveness: the 'beautiful is good' stereotype can make attractive defendants seem less guilty. Sigall and Ostrove (1975) found mock jurors were more lenient to an attractive defendant accused of burglary, but harsher when the crime used attractiveness (a swindle), suggesting jurors judge whether attractiveness was exploited. Later studies are mixed.
• Race: in-group/out-group bias may make jurors harsher to defendants of a different race. Bradbury and Williams (2013), the compulsory contemporary study, found juries with a higher percentage of White or Hispanic jurors were more likely to convict Black defendants in real felony cases.

Pre-trial publicity

Pre-trial publicity (PTP) is media coverage before a trial, often negative information that would not be allowed as evidence. Jurors may form opinions before the trial and later misremember PTP details as trial evidence (source monitoring errors). Ruva et al. (2007) found exposed mock jurors gave more guilty verdicts, rated the defendant less credible and attributed PTP-only information to the trial. Judges' instructions to ignore PTP have limited effect; remedies include delaying the trial or moving it to another area.

Expert testimony: Penrod and Cutler (1989)

Should psychologists tell juries about eyewitness reliability? Penrod and Cutler reviewed their mock jury research:

• Mock jurors watched a videotaped robbery trial (about 45 minutes) in which the key evidence was the victim's identification. Ten factors were varied across 64 versions (disguise, weapon visibility, retention interval, line-up instructions, witness confidence and more).
• Without an expert, only witness confidence affected verdicts: 51% convicted when the witness was 100% confident versus 37% at 80%, although confidence is a weak predictor of accuracy. Jurors remembered the other factors but did not use them.
• In the expert testimony study (538 students), an expert made jurors more sensitive to witnessing conditions such as weapon focus and gave less weight to confidence. A related study (Cutler, Penrod and Dexter, 1989) found expert testimony did not simply make jurors more sceptical of all eyewitnesses.

Evaluation

• Mock jury research gives control and allows variables to be manipulated ethically (real jury deliberations are confidential), so it can show cause and effect.
• But mock jurors are often students, know their verdict has no consequences and watch shortened trials, so validity and generalisability are limited. Bradbury and Williams used real verdicts (higher validity) but could not control other differences between cases.
• Practical application: jury selection, judges' instructions, rules on media reporting, and whether to allow expert witnesses.

Worked example

In Penrod and Cutler's research, 51% of jurors convicted when the witness was 100% confident and 37% when 80% confident. What does this show?

1. Conviction rose by 14 percentage points with higher confidence.
2. Confidence is only weakly related to accuracy, so jurors relied on a poor cue.
3. This supports using expert testimony to make jurors aware of better cues, such as witnessing conditions.

Answer: Jurors over-rely on witness confidence.

Check yourself

1. Sigall and Ostrove (1975) found an attractive defendant was treated more harshly when
   • the crime was burglary
   • no crime was described
   • the crime used her attractiveness, as in a swindle
   • the jurors were all students
   Show answer

   the crime used her attractiveness, as in a swindle. Attractiveness linked to the crime reversed the leniency.

2. Pre-trial publicity is
   • media coverage of a case before the trial
   • evidence given by an expert
   • the judge's summing-up
   • a juror's attractiveness
   Show answer

   media coverage of a case before the trial. Coverage before the trial.

3. A juror believes a detail from a newspaper was presented in court. This is
   • weapon focus
   • the other-race effect
   • a source monitoring error
   • a Type II error
   Show answer

   a source monitoring error. Confusing the source of a memory.

4. Penrod and Cutler found 51% convicted with a 100% confident witness and 37% with an 80% confident witness. What is the difference in percentage points?
   Show answer

   14 percentage points. 51 - 37 = 14.

5. What effect did expert testimony have in Penrod and Cutler's research?
   • Jurors ignored all eyewitness evidence
   • Jurors relied more on witness confidence
   • It had no effect at all
   • Jurors became more sensitive to witnessing conditions and relied less on confidence
   Show answer

   Jurors became more sensitive to witnessing conditions and relied less on confidence. Expert testimony improved sensitivity.

6. Why do researchers use mock juries?
   • Mock juries always give real verdicts
   • Real jury deliberations cannot be studied directly, and variables can be manipulated
   • Mock juries have higher ecological validity than real juries
   • They are required by law
   Show answer

   Real jury deliberations cannot be studied directly, and variables can be manipulated. Control and access.

7. Explain how pre-trial publicity may influence jury decision-making.
   Show answer

   Negative media coverage before the trial can create a belief that the defendant is guilty, and jurors may confuse information from the media with trial evidence, making them more likely to convict.. Media plus effect on the juror.

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Sources

• Pearson Edexcel International Advanced Subsidiary/Advanced Level in Psychology specification, Issue 6 (November 2024, first assessment January 2026)
• Penrod and Cutler (1989), Eyewitness expert testimony and jury decisionmaking, Law and Contemporary Problems 52(4)
• NCJRS abstract: The eyewitness, the expert psychologist and the jury (Cutler, Penrod and Dexter, 1989)
• Frontiers in Psychology (2019): facial attractiveness and punishment (review of the leniency effect, Sigall and Ostrove, 1975)
• Pearson IAL Psychology summary of studies: WPS03
• Pearson WPS03/01 examiners' report, January 2025

Last updated 8 November 2026. Spotted a mistake? Tell us.