Lecture 2: Eyewitness Memory

Background

• Eyewitness testimony is commonly used as evidence in court and is one of the most persuasive forms of evidence for juries (Wells, Lindsay, & Ferguson, 1979).
• Eyewitness memory is typically assessed in two ways: recall memory and recognition memory.
• Recall memory involves reporting details of a previously witnessed event or person.
• Recognition memory involves reporting whether what is currently being viewed or heard is the same as the previously witnessed person or event of interest.

Estimator Variables and System Variables

• There are two types of factors that can affect eyewitness memory: estimator variables and system variables.
• Estimator variables are present at the time of the crime and cannot be changed.
• System variables can be manipulated after the fact and impact the accuracy of witnesses.

Estimator Variables

• Many features of an event can influence a person's perception, such as exposure time, lighting, distance, physical disguise, and distraction.
• Witnesses can view the same thing and perceive it differently due to different expectations, beliefs, and current knowledge.
• Context can affect our perception of events, and there is an own race bias, where people have difficulty identifying people of another race.
• "Flashbulb memory" is a vivid memory of a specific event, and emotional level can affect memory, with optimal memory at an optimal level of arousal.
• The Easterbrook hypothesis states that highly aroused witnesses have better memory for central details than peripheral details.
• The weapons focus effect states that the presence of a weapon draws attention and impairs a witness' ability to identify a culprit.

System Variables

• The delay between witnessing an event and giving a statement can affect memory.
• Questioning techniques used by the police can affect eyewitness accuracy, and the misinformation effect can cause people to incorporate incorrect information into their memories.

Misinformation Effect

• The misinformation effect is a phenomenon where people incorporate incorrect information into their memories after being exposed to it.
• Research by Elizabeth Loftus (1975) demonstrated the misinformation effect, where participants who were asked leading questions later incorporated incorrect information into their memories.

False Memory Research

• Research by Wade et al. (2002) showed that participants can be convinced of false memories through repeated interviews and suggestive questioning.
• Research by Braun et al. (2002) showed that participants can be convinced of false memories through suggestive advertising.

Repressed / False Memories

• There is a debate about whether repressed memories are real or false, with some arguing that therapists can implant false memories in patients.
• Others believe that memories can be repressed and later recovered through therapy.

Implications of the Misinformation Effect

• The misinformation effect has implications for the credibility of eyewitness testimony, as questioning techniques can affect the accuracy of witness memories.
• Factors that increase susceptibility to the misinformation effect include age, hypnosis, suggestibility, credible source of misinformation, repetition of misinformation, and peripheral misinformation.