Psychology & Law notes

Updated April 8, 2021

Jumbo Month lecture by Professor Sam Sommers on April 8, 2021.

  • Psychology really is:
    • Clinical psychology (analyzing people, psychological disorders)
    • Psychophysiology and Neuroscience
    • Developmental psychology (how children and adults develop)
    • Cognitive psychology (how we think and remember)
    • Social psychology (everyday life, communication, judgements about one another)
  • When someone might be lying we often look for anxiety, but we don't know whether this anxiety comes from needing to come up with a lie or telling an embarrassing truth.
  • It's really hard to accurately detect deception from a video. In a study with different groups of people (police, psychiatrists, college students), only U.S. Secret Service agents were slightly better than chance at detecting lies.
    • However, the task in this study involved watching a video, without the ability to ask further questions.
  • Detecting deception can be broken across four channels of communication: words, face, body, and voice.
    • Words and face are fairly controllable, while body and voice are less controllable.
  • Few types of evidence are as persuasive to a jury as eyewitness account. However, more than 3/4 of DNA exoneration cases by The Innocence Project included a confident, incorrect eyewitness.
  • Eyewitness memory variables:
    • Estimator variables has to do with the scene itself (brightness in the area, race of the person, the amount of time you get to see the person, etc).
    • System variables have to do with the legal system (how many photos are in the lineup, how they're presented, etc).
  • Eyewitnesses pick from a lineup using process of elimination; they often just pick the person who looks the closest to what they remember, but the real perpetrator might not be in the lineup.
  • To make false identifications less common:
    • Make clear that the person might not be in the lineup.
      • Massachusetts has required as a best practice to tell you that the person might not be in the lineup.
    • Show each photo one at a time, so eyewitnesses don't compare the faces to one another.
    • Do a double-blind lineup, where the police officer and the eyewitness both don't know whether the suspect is actually in the lineup.