PsychologicalMANIPULATIVE

Misinformation Effect

What it is

Information encountered after an event — a leading question, a co-witness's account, a news report — becomes incorporated into memory of the event itself, so that people sincerely remember details they never saw.

How it works

Memory is reconstructive: retrieval rebuilds an episode from fragments plus whatever is available at the time, and the rebuilt version is then stored as if it were the original. Loftus and Palmer showed in 1974 that asking how fast cars were going when they “smashed” rather than “hit” raised speed estimates and, a week later, made witnesses more likely to recall broken glass that was not in the film. Three decades of follow-up, summarised by Loftus in 2005, established that the effect grows with delay, with source credibility, and with the plausibility of the inserted detail, and that entire false events (being lost in a shopping mall as a child) can be implanted in a substantial minority of adults. The recipient has no phenomenological warning: implanted memories feel as vivid and confident as real ones. Deliberately supplying post-event misinformation, whether through questioning, repeated “recaps,” or advertising that rewrites a past experience, is deception by design, though interviewers, therapists and journalists also produce it inadvertently.

Real-world examples

  • •In Loftus and Palmer's 1974 experiments, changing one verb in a question about a filmed collision altered both speed estimates and later memory for non-existent broken glass.
  • •Braun, Ellis and Loftus found in 2002 that an advertisement describing a childhood meeting with Bugs Bunny at Disneyland led some participants to remember it happening, though Bugs is a Warner Bros. character.
  • •The 1980s and 1990s “recovered memory” cases, in which suggestive therapy techniques produced confident but unsupported memories of abuse, prompted the research programme on implantation and a wave of retracted accusations.
  • •Co-witnesses who discuss an event before giving statements converge on shared details, including errors; police guidance now separates witnesses for this reason.

Ethical guidelines

  • ●Never introduce details into questions or recaps that the other person did not supply; open questions (“what did you see?”) before specific ones.
  • ●When you must inform someone of something they may not have witnessed, label it clearly as coming from you, not as a reminder of what they saw.
  • ●Do not use advertising, testimony preparation, or relationship “recaps” to reshape someone's memory of a past experience.

How to defend against it

  • ►Record your own account of an important event as early as possible, before discussing it with anyone; refer back to it rather than to later conversations.
  • ►When someone “reminds” you of a detail, ask yourself whether you remember the detail itself or only their telling of it, and say so: “I don't recall that; I recall you saying it.”
  • ►Notice embedded details in questions (“the man with the gun,” “after you agreed”) and answer the presupposition first: “I didn't see a gun.”
  • ►For disputes about what happened, prefer contemporaneous records — messages, receipts, timestamps — over anyone's reconstructed memory, including your own.
  • ►Be especially cautious of vividness and confidence as signs of accuracy; implanted memories are as vivid as real ones.

References

  1. Loftus, E. F., & Palmer, J. C. (1974). Reconstruction of automobile destruction: An example of the interaction between language and memory. Journal of Verbal Learning and Verbal Behavior, 13(5), 585-589 · link
    The smashed/hit verb manipulation altering speed estimates and later false recall of broken glass.
  2. Loftus, E. F. (2005). Planting misinformation in the human mind: A 30-year investigation of the malleability of memory. Learning & Memory, 12(4), 361-366 · link
    Review of moderators (delay, credibility, plausibility) and of whole-event implantation including the lost-in-the-mall paradigm.
  3. Braun, K. A., Ellis, R., & Loftus, E. F. (2002). Make my memory: How advertising can change our memories of the past. Psychology & Marketing, 19(1), 1-23
    The Bugs Bunny at Disneyland advertising study.
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