Week 5 Long Misinformation and False Memories in Forensic Psychology

The Misinformation Effect

• Definition and Core Concept: The misinformation effect occurs when post-event information is integrated into a person's memory of an event, leading to the report of false details. This suggested information becomes part of the person's internal narrative of what happened.

• The Integration of Language into Memory: Subtle changes in language can significantly alter memory recall.

  • In a foundational study, participants were asked to estimate the speed of cars in a collision using different verbs in the question:
    • "About how fast were the cars going when they smashed into each other?" yielded higher speed estimates than verbs like "hit" or "contacted."
  • (Loftus et al., 1978) established that after viewing a picture and subsequently reading information about it, suggested details from the text are often incorporated into the participant's final report.

• Conveyance of Misinformation: Post-event information can come from multiple sources, including police interviewers, therapists, or the media. It is conveyed through various methods:

  • Leading Questions: Phrasing questions to imply a specific answer (e.g., focusing on the verb "smashed").
  • Presentation of Modified Details: Substituting one object for another (e.g., replacing a stop sign seen in an image with a yield sign in a description).
  • Presentation of Non-Existent Details: Suggesting the presence of something that was never there (e.g., asking about a stop sign when none existed).

• The Oklahoma Bombing Example (1995): Following the arrest of Timothy McVeigh, a question arose regarding an accomplice.

  • Three key witnesses at a truck hire shop provided conflicting accounts initially.
  • One witness claimed McVeigh was with a second man, while the other two witnesses did not recall anyone else.
  • After the witnesses discussed the events together, eventually all three claimed to remember details of this second person.
  • The witnesses admitted to discussing their memories, raising the question of whether this was genuine reminiscence or memory contamination.

Co-Witness Discussions

• Prevalence: Co-witness discussion is common in forensic contexts. One study found it occurred in $58\%$ of real-world cases (Skagerberg & Wright, 2008).

• Laboratory Findings: In controlled settings, $71\%$ of witnesses incorporated misinformation provided by a co-witness into their own memory reports (Gabbert et al., 2003).

• Factors Influencing Impact:

  • Confidence: Misinformation integration can occur even for memories held with high confidence (Horry et al., 2012).
  • Relationship: The effect is stronger among friends or partners compared to strangers (Hope et al., 2008).
  • Memory Blends: These discussions cause at least some "memory blends," suggesting actual memory alteration rather than simple compliance with the peer (Skagerberg & Wright, 2008).
  • Source Monitoring Errors: These occur when individuals forget or confuse the source of the information (e.g., believing they saw something themselves when they actually heard it from another witness).

• Investigative Implications: Investigators, judges, and jurors must be aware of these effects. To maintain evidence integrity, investigators should strive to prevent witnesses from discussing the event before providing statements.

Source Monitoring

• Definition: Source monitoring involves the cognitive processes used to distinguish between different types of memories, specifically true memories (experienced externally) versus false or imagined ones (generated internally).

• Characteristics of True vs. False Memories: (Johnson, Foley, Suengas, & Raye, 1988)

  • Sensory and Perceptual Detail: True memories generally contain more visual, sound, smell, and taste information.
  • Contextual Detail: True memories typically include more information regarding time, location, and the spatial arrangement of objects.

• Situational Factors Affecting Source Monitoring:

  • Ambiguity: Based on Tuckey & Brewer (2003), more ambiguous events lead to more source errors. Individuals are likely to replace ambiguous details with schema-consistent information.
  • Completeness of the Event: If an event is perceived as incomplete, source errors are more likely. When shown a series of slides depicting an event with gaps, participants often "fill in" the missing sections and are specifically more likely to create false memories for peripheral, non-central information.

• Individual Differences:

  • Working Memory Capacity (WMC): WMC involves the ability to direct attentional resources. Individuals with greater WMC are generally less susceptible to source monitoring errors.
  • Age: Older adults (Johnson et al., 1993) often have more difficulty recalling context, such as whether they actually performed an action or merely watched someone else do it.
  • Children: Generally more susceptible to source monitoring errors (Ceci & Bruck, 1993). They have been shown to report thought-about or imagined events as real experienced events (Ceci et al., 1994).

False Memories: Formation and Evidence

• The "Memory Wars": This refers to the debate regarding whether recovered memories of abuse are genuine or false. Empirical evidence does not provide definitive conclusions for individual cases but addresses the mechanisms behind memory formation and recovery.

• Three-Step Model of False Memory Creation: (Hyman et al., 1998; Mazzoni et al., 2001)

  1. The person must perceive the target event as plausible.
  2. The person must come to believe the event actually happened.
  3. The person reinterprets images and narratives to form a cohesive memory.
  • Belief vs. Memory: It is possible to believe an event occurred (e.g., being born) without having a memory of it. Conversely, there are "non-believed memories" where a person has a memory they no longer believe is true, such as Jean Piaget's false memory of being kidnapped as a child.

• Childhood Experience Studies:

  • "Lost in the Mall": (Loftus et al.) Participants read journal extracts of true childhood events alongside one false event (being lost in a mall). $7$ out of $24$ adults "remembered" the false event, providing either full or partial recall.
  • Plausibility Limits: Subsequent studies tested the limits of creating false memories. While participants could be convinced they were attacked by an animal (Porter et al., 1999), ruined a wedding (Hyman et al., 1995), or were saved by a lifeguard (Heaps & Nash, 2001), they were unlikely to develop memories for demonic possession (Mazzoni et al., 2001) or a rectal enema (Pezdek et al., 1997).

• The Role of Photographs:

  • Balloon Ride Study: (Wade et al., 2002) Using doctored photos showing children on a hot air balloon, $50\%$ of participants eventually "remembered" the event after three interviews conducted over a span of $7$ to $16$ days.
  • Non-Relevant Photos: Even non-relevant photos, such as an old school yearbook photo, can increase the likelihood of forming false memories (e.g., for a "slime" incident) (Lindsay et al., 2004).

Properties and Implications of False Memories

• Reality of False Memories: False memories can feel entirely real to the individual.

  • Betting Studies: (Weingardt, Toland, & Loftus, 1994) Participants were willing to bet actual money on the accuracy of their false memories.
  • Behavioral Consequences: (Geraerts et al., 2008) Creating a false memory for becoming ill after eating egg salad led to long-term behavioral changes. Participants avoided egg salad during food tasting sessions immediately, one week later, and even four months later.

• Repression and Suppression: Anderson et al. (2001, 2004) investigated the ability to intentionally forget words, observing different brain activity patterns. However, critics note that participants still remembered a high percentage of "suppressed" items ($80\%$ vs. $87\%$ in the control group), suggesting this may be evidence of trying to forget rather than successful repression.

• Other Mechanisms: Forgetting of Prior Remembering: (Geraerts et al., 2006) Forgetting and recovery might depend on context.

  • Context Dependency: If words like "FLIGHT" or "BANK" are studied in specific contexts (BIRD-FLIGHT, RIVER-BANK), they are easier to recall when tested in the same context than in a different one (STAIRS-FLIGHT, MONEY-BANK).
  • Recovery Contexts: Individuals who spontaneously recover memories of abuse often have context-dependent memory systems, and these memories are frequently corroborated by external evidence. In contrast, memories recovered through suggestive therapy are rarely corroborated (Geraerts et al., 2009).

• Current Scientific Opinion: Scholars like Brewin & Andrews (2016) suggest that the occurrence of false memories of entire events (as opposed to minor details) may be relatively rare compared to earlier estimates.