Jury Decision Making and Deliberation Study Notes

The jury is composed of 12 individuals who act as "fact finders" in a criminal case.
The trial aims to provide these jurors with all necessary information to reach a verdict.
Jurors process case-related information through two primary models:
- The Mathematical Model
- The Story Model

This model compares jurors' interpretation of evidence to a mathematical formula or meter.
- Jurors assess guilt or innocence based on the evidence presented at trial.
- Their determination can fluctuate based on the strength of the evidence.
- Some evidence types may have a significant impact, potentially “freezing” the meter (Hastie, 1993; Vidmar & Harris, 2007).
However, critics argue this model overestimates jurors' rational calculation processes, as jurors’ reported thought processes do not align with this mathematical approach (Devine & Malken, 2016).

According to this model, jurors create a narrative from the evidence presented during the trial to decide on a verdict.
- These narratives help jurors interpret evidence (Costanzo & Krauss, 2021).
- The jury's verdict aligns with the narrative constructed in comparison to arguments made by the prosecution and defense (Devine, 2012; Simon, 2012).
Research indicates that the story model is effective in murder, rape, and sexual harassment cases (Huntley & Costanzo, 2003; Olsen-Fulero & Fulero, 1997; Pennington & Hastie, 1992).
Deliberation among jurors aims to consolidate a unified narrative of the case (Levett & Devine, 2017).

The primary predictor of a jury's verdict is the strength of the evidence presented (Taylor & Hosch, 2004).
- This includes crucial evidence relevant to the charges, such as the murder weapon (Devine, 2009; Costanzo & Krauss, 2021).
Other influencing factors in the jury’s assessment of evidence include:
- Negative pre-trial publicity
- Severity of the charges
- Complexity of the case
These variables become significantly impactful when evidence is ambiguous, often referred to as the liberation hypothesis (Kalven & Zeisel, 1966).

Voir dire is meant to identify impartial jurors, yet true impartiality is challenging to achieve.
Jurors enter proceedings with preconceived notions and implicit biases that can affect their decision-making.
Factors influencing jurors include:
- The defendant's characteristics, such as attractiveness
- The ability to disregard inadmissible evidence
- Understanding of complex expert testimony
- Interpretation of impeachment evidence

Attractiveness:
- Studies (Mazzella and Feingold, 1994) show attractive defendants receive more leniency compared to less attractive ones, unless attractiveness is relevant to the crime context (e.g., financial schemes).
Race:
- Jurors' decisions may be influenced by the defendant's race, especially if it aligns with stereotypes (e.g., a stepfather accused of sexual abuse), leading to harsher treatment (Costanzo & Krauss, 2021; Smalarz et al., 2018).
Inadmissible evidence:
- Information excluded from the trial due to prejudicial nature can still influence jurors.
- Examples include hearsay or questions deemed leading.
Judicial process:
- When an objection is raised concerning inadmissible evidence, a judge must either sustain or overrule the objection, affecting the jurors’ exposure to that information.
- Sustained objections instruct jurors to ignore the information, which is often difficult (Costanzo & Krauss, 2021).

The difficulty jurors face in ignoring inadmissible evidence relates to:
- Ironic processes: The tendency to focus on the very information they are instructed to ignore (Costanzo & Krauss, 2021).
- Reactance theory: Jurors may perceive judicial instructions as encroaching on their freedom, leading them to retain the information regardless (Brehm & Brehm, 1981).
Study by Pickel (1995):
- Evaluated jurors' disregard for inadmissible information involving hearsay and past criminal convictions.
- Results revealed that jurors were less likely to disregard hearsay than criminal history, shaped by perceptions of fairness (Costanzo & Krauss, 2021).

Jurors must interpret complex evidence from expert witnesses, such as psychologists or forensic scientists.
- Experts play a vital role, explaining technical information relevant to the case.
Challenges arise when jurors struggle with technical jargon, leading them to rely on perceived expert credentials as a guide to credibility (Costanzo & Krauss, 2021).

Impeachment evidence is information aimed at discrediting a witness, influencing juror trust in testimonies (Costanzo & Krauss, 2021).
Jurors may draw broader conclusions based on impeachment evidence beyond its intended use.

Jury process characteristics:
- Jurors are often strangers meeting for the first time.
- They must reach a consensus without being able to ask clarifying questions.
- Retention of complex information can be challenging.
- They work under a legal framework that might not be fully understood.
The jury’s composition notably influences its dynamics and decision-making (Costanzo & Krauss, 2021).

The U.S. jury system traditionally utilizes a 12-member panel, derived from English law.
- The legal precedent from Williams v. Florida (1970) allows a minimum of 6 jurors for non-capital cases.
- The 12-member structure typically enhances jury decision quality (Saks, 1997; Costanzo & Krauss, 2021).
- Research indicates larger juries yield better recall, consistent verdicts, and better representation of community perspectives (Saks, 1996).

Study by Sommers (2006):
- Examined how racial composition affects jury deliberation.
- Findings highlighted that diverse groups led to more thorough discussions and better memory recall amongst jurors.
- Heterogeneous groups can mitigate implicit racial bias (Peter-Hagene et al., 2019).
Diversity may increase the quality of deliberations, fostering better decision-making despite potential tension (DeGrassi et al., 2018).

Certain jurors, deemed "strong jurors" for their influence, are often articulate, well-educated, and possess higher social standing (Costanzo & Krauss, 2021).
Majority influence:
- Kalven and Zeisel (1966) found that juries tend to adhere to initial majorities, with a substantial agreement taking place in most cases.

The foreperson acts as a representative of the jury, fulfilling organizational duties rather than serving as a strong influencing force.
Selection of the foreperson typically occurs quickly, sometimes based on personality traits or background suitability (Kerr et al., 1999).

In instances of divided opinions, the leniency bias suggests jurors may lean towards finding the defendant not guilty (Kerr and MacCoun, 2012).
This tendency relates to the undeniable burden of proof present in criminal cases, as the standard is “beyond a reasonable doubt,” reflecting doubt in determining guilt based on evidence.