Notes on Wrongful Convictions and Eyewitness Testimony

  • Course Information

    • Course Code: PSYC335
    • Instructor: Dr. Julia Yesberg
    • Topic: Wrongful Convictions and Eyewitness Testimony

  • Research Findings on Eyewitness Confidence

    • Study by Laura Smalarz and Gary L. Wells
    • Investigated the effects of multiple doses of feedback on eyewitness confidence.
    • Experiment 1: Participants made mistaken identifications and received feedback.
      • Types of feedback:
      1. Co-witness feedback
      2. Vague feedback (e.g., "You've been a good witness")
      3. Inference-based feedback
      • Results: Co-witness and inference feedback independently increased confidence.
    • Experiment 2: Variability in feedback types to examine cumulative effects on confidence.

  • Judicial Outcomes

    • Possible outcomes of court decisions:
    • Convicted
    • Acquitted
    • Correct conviction
    • Incorrect acquittal
    • Not Guilty
    • Incorrect conviction
    • Correct acquittal

  • Blackstone's Ratio

    • Quote: "It is better that 10 guilty persons escape than that one innocent suffer."

  • Public Opinion on Wrongful Conviction

    • Survey questioning how many guilty individuals should be acquitted to prevent an innocent person's wrongful conviction.
    • Rates of acceptance vary by crime type: Shoplifting, Burglary, Rape.

  • Prevalence of Wrongful Convictions

    • Overall error rate in the justice system is difficult to ascertain (Simon, 2006).
    • Estimates range from 3.3% to 5% (Risinger, 2007).
    • Significant discomfort expressed by the public regarding even a 3.3% rate.
    • 375 DNA exonerations (1989-2020) in the USA, contributing factors:
    • Informants
    • False confessions
    • Bad science
    • Eyewitness misidentification
      • Eyewitness misidentification linked to a high percentage of wrongful convictions.
      • 80% of cases linked to this factor.
      • Other variables include:
        • 17% informants
        • 29% false confessions
        • 43% bad science

  • Reliability of Eyewitness Testimony

    • Jurors often place heavy weight on eyewitness testimony (Cutler et al., 1990).
    • Reality: Eyewitness testimony can be highly unreliable.
    • Human memory is malleable and can be distorted.

  • Memory Processes Involved in Eyewitness Testimony

    • Encoding: Information transforms into a storable format.
    • Storage: Data is retained for future recall.
    • Retrieval: Accessing stored information to bring it into consciousness.

  • Estimator vs System Variables

    • Estimator Variables: Details of the event affecting accuracy (e.g., encoding and storage), not under control of the justice system.
    • Examples: Exposure time, lighting conditions, stress, race of witness/culprit, presence of weapons.
    • System Variables: Factors influenced by the legal system primarily related to retrieval, controllable to enhance accuracy.

  • Cross-Race Effect

    • Witnesses are typically better at recognizing faces of their own race compared to others (Meissner & Brigham, 2001).

  • Weapon Focus Effect

    • Eyewitnesses exposed to armed crimes often have poorer recall of other details due to the weapon drawing focus (Steblay, 1992).

  • Impact of Stress on Memory

    • Optimal levels of stress can enhance performance but excessive stress impairs encoding and reduces accuracy (Christianson, 1992).

  • Memory Over Time

    • Memory is not static; it changes and is subject to distortion over time.

  • Post-event Information and Misinformation Effect

    • Exposure to misleading information after the event can lead to incorrect recall (Loftus, 1975, Loftus et al., 1978).
    • Leading Questions: The verbiage used can significantly influence recall, such as varied suggestions for collisions.

  • Co-witness Contamination

    • Witnesses can influence each other's memories, leading to inaccuracies (Gabbert et al., 2003).

  • Best Practices for Eyewitness Identification

    • Implement evidence-based practices to reduce errors, such as proper line-up construction and administration:
    • Ensure that fillers resemble the suspect, help to reduce false IDs.
    • Use simultaneous vs. sequential line-ups based on the purposefulness of minimizing relative judgments.

  • Cognitive Interviews

    • An effective method for eliciting detailed eyewitness accounts involves visualization, contextual recall, reverse order recollections, and reports from different perspectives (Memon et al., 2010).

  • Conclusion

    • Eyewitness errors are significant contributors to wrongful convictions.
    • Understanding both estimator and system variables helps illuminate areas for improvement in legal processes.
    • Adoption of improved police procedures can enhance eyewitness accuracy.