What is malleability of memory?

Elizabeth Loftus, answered from the texts and cited to the page.

Elizabeth Loftus answers

Memory is not a videotape. It does not record experience and play it back unchanged — it reconstructs, and in that reconstruction it is vulnerable.1 The core of what I mean by malleability is this: memories can be altered, supplemented, or created anew by information that arrives after the original event, by imagination, by the leading questions of others, and by the ordinary passage of time.2

The experimental work makes the mechanism concrete. When people watch a film of an accident and are later asked how fast the cars were going when they "smashed" into each other, they report higher speeds than people asked the same question with the verb "hit." Post-event information can cause subjects to misremember a green car as blue, a yield sign as a stop sign, or to recall broken glass that was never there.3

A whole barn — large and conspicuous — has been remembered by people who never saw one.4 What makes this perplexing rather than merely curious is that inaccurate memories can feel exactly as compelling and real as accurate ones.5 There is no internal signal that announces the distortion. And the susceptibility is not confined to a particular type of person — research examining individual differences across multiple false-memory paradigms finds no reliable "false memory trait," no one personality or cognitive profile that is specially immune.6

There are probably sound evolutionary reasons for a malleable memory. A system that updates, discards the obsolete, and keeps only what remains biologically useful or personally meaningful is more economical than one that tries to preserve everything unchanged.7 The trouble is that the same flexibility that serves us well day to day leaves us open to contamination — from suggestion, from leading questions, from the different recollections of people we trust.8

Rehearsal helps. People who are warned that someone may try to alter their memories, and who then rehearse what they actually experienced, are better able to resist misinformation than people given no such warning.9 But that is a partial remedy, not a solution, because most of us do not know when to be on guard. The legal implications follow directly.

If a witness's memory feels certain, that feeling is not evidence of accuracy. The question a court should be asking is not how confident the witness is, but what happened to that memory between the event and the testimony.

Sources

  1. memory more closely resembles a synthesis of experiences than a replay of a videotape.
    Our changeable memories- legal and practical implications, pp. 1–2
  2. Many influences can cause memories to change or even be created anew, including our imaginations and the leading questions or different recollections of others.
    Our changeable memories- legal and practical implications, pp. 1–2
  3. When exposed to misleading post-event information, subjects have misrecalled the color of a car that was green as being blue, a yield sign as a stop sign, broken glass or tape recorders that never existed.
    Who remembers what- Gender differences in memory, pp. 15–16
  4. even recalled something as large and conspicuous as a barn when no barn was ever seen.
    Who remembers what- Gender differences in memory, pp. 15–16
  5. Inaccurate memories can sometimes be as compelling and 'real' as an accurate memory.
    Our changeable memories- legal and practical implications, pp. 1–2
  6. it seems likely, therefore, that there is no false memory 'trait'. In other words, no one type of person seems especially prone, or especially resilient, to the ubiquity of memory distortion.
    Who is susceptible in three false memory tasks, p. 2
  7. There may therefore be sound economic reasons for discarding some information altogether, for updating memory, and for relegating less useful memories to rear dusty mental files.
    Memory, Surprising New Insights Into How We Remember and Why We Forget, pp. 208–213
  8. our memory processes can be vulnerable to contamination and distortion. Our memories are malleable, susceptible to influence from suggestion, and can even contain whole events that never actually occurred.
    Who is susceptible in three false memory tasks, p. 2
  9. Research has shown that people who are warned that someone may try to change their memories can better resist these influences than people who are not warned. The mechanism by which people resist is twofold: They rehearse the experience, and they better scrutinize the new information to detect inconsistencies with their already-stored memory.
    Memory, Surprising New Insights Into How We Remember and Why We Forget, pp. 208–213