7.17 Eyewitness Testimony and Memory Reliability

Eyewitness Testimony

Overview

  • Discussion of the reliability of eyewitness testimony as a form of evidence.

  • Implications of memory in evaluating eyewitness accounts.

Issues with Eyewitness Testimony

  • Eyewitness testimony is portrayed in media as a reliable form, typically through dramatizations involving lineups.

  • However, studies show significant unreliability in eyewitness accounts.

DNA Exoneration Cases

  • Examination of the first 225 cases of DNA exoneration:

    • DNA evidence revealed wrongful convictions.

    • Approximately three quarters of these cases involved eyewitness testimony as the primary evidence.

Impact on Juries

  • Eyewitness testimony can heavily influence jury decisions.

  • Confident witnesses can sway juries even when their memories may not be accurate.

    • Example: A confident statement from a witness can create a strong impression of validity.

Case Study: Ronald Cotton

  • Ronald Cotton's wrongful imprisonment for the rape of Jennifer Thompson:

    • Cotton was identified in a lineup as the rapist by Thompson.

    • Initial identification was tentative, followed by an increase in confidence over time, raising concerns about memory reliability.

    • Highlighted the problematic nature of increasing confidence in a mistaken identification.

  • Post-exoneration relationship:

    • Cotton and Thompson developed a friendship and advocated for improved procedures in police lineups.

Psychological Mechanisms Behind Errors

  • Familiarity and source memory explain errors in eyewitness identification.

Research Experiment

  • Description of an experiment demonstrating the fallibility of eyewitness testimony:

    • Participants observed a staged crime and were later shown mugshots of individuals, none of whom were present at the crime.

    • Four to five days post-viewing the staged crime, participants were asked to identify the suspect from a lineup.

    • Result: Approximately 29% error rate, where participants mistakenly identified innocent individuals as the perpetrator.

Analysis of Results

  • Explanation of findings related to familiarity and source memory:

    • Immediate lineup identification would typically involve both source memory (recognizing where the person was seen) and familiarity.

    • Over time, as the source of memory fades, participants rely solely on familiarity, leading to faulty conclusions.

    • Resulting inference often: Familiarity = likely guilty, despite the absence of actual recollection of the event.

Conclusion

  • Eyewitness testimony is a complex issue intertwined with psychological factors, the influence of time on memory, and the persuasive power of confidence, resulting in a significant potential for wrongful convictions.