BHS 499-07Memory and Amnesia

Memory and Reality

Source Monitoring

Source monitoring – the ability to keep track of where a memory came from.• Accurate source judgments can be made on

partial or vague information using familiarity.

• Source is integrated into the memory trace.

The search for source information is controlled by prefrontal lobes whereas retrieval involves temporal lobes.

Types of Source Information

Several criteria are used to make judgments about the source of information:• Perceptual information

• Contextual information

• Expectedness of the source

• Semantic detail or affective information

• Cognitive operations during original experience

Types of Source Monitoring

Internal – distinguishing what you thought about doing from what you actually did.

External – distinguishing between two external sources (who said what?)

Reality monitoring – distinguishing memories of what really happened from what was imagined.

Source Monitoring Errors

Information about source grounds memories in reality.• Repeated attempts to remember can increase

likelihood of confusing a real event with an imagined one.

• Repeated attempts to remember introduce perceptual qualities to the memory through imagination, making the memory seem real.

Choices distort memories for qualities.

Source Cueing

Source cueing – when the source is used as a retrieval cue to aid memory.• Knowledge about the source can be used to

narrow down choices during recall.

• Timbre is a perceptual quality of the source of a melody that can identify the instrument played and aid memory for the song itself.

Cryptomnesia

Not all plagiarism is intentional. Cryptomnesia – when a person recalls a

previously encountered idea without realizing the original source.• The idea is mistakenly believed to be an

original thought.

This is a reality monitoring failure – the source is lost or was never encoded.

False Fame

Familiarity increases when information is repeatedly presented.

False fame effect – the tendency to think someone is famous because their name sounds familiar.• Unfamiliar names previously viewed on a list

were considered more famous the next day.

There is a preference for the familiar.

Sleeper Effect

When we first encounter information, the credibility of the source affects our acceptance of it.

Later, when the source is forgotten, the information may gain (or lose) credibility compared to when first received.

Conditions for the effect: (1) attention to the info; (2) source presented second; (3) must rate trustworthiness immediately afterward.

False Memories

False memory – when people recall something that never happened.

Deese-Roediger-McDermott Paradigm for creating false memories:• Present a list of words associated with

another word that is not presented, e.g. sleep.

• On testing, people are likely to recall “sleep”.

• Associations prime the not-presented word.

Conditions for False Memory

The more associations, the more likely the false memory will occur.

The less recallable the actual items are, the more reconstruction is needed and the more likely a false memory.• More likely with partial or fuzzier recall.

Pictures less likely to show the effect.

Influences on False Memory

When people are directed to forget the list, false memory goes up.

Part-set cueing is extended to the not-presented word, so false memory goes down.

If the not-presented word is more emotional, false memory declines.

Influenced by conformity & expectation.

False Memory from Integration

Information from different points in time becomes integrated into a single memory.• Several things are misremembered as the

same event.

Bransford & Franks – overlapping content is more likely to be integrated.• Ants ate sweet jelly on the table.

Implanted Memories

Loftus deliberately planted false memories in people.• The content of a question about the past

becomes part of what is later remembered.

The more plausible the information, the more likely it will be implanted, but the implausible can be implanted.

Imagination Inflation

Imagining an event, real or false, increases confidence in the memory for that event.

Viewing pictures makes false memory more likely.

Students can develop their own false memories by answering questions they know to be false.

Qualities of False Memories

True memories are more often:• Richer in detail, more emotional

• More likely to be “recollected” field memories.

False memories are more often:• Stereotypical events

• “Known” observer memories

These qualities cannot be used to distinguish the true from false because of overlap.

Hypnosis & Memory

Hypnosis – an altered state of consciousness in which a person is more willing to accept & follow suggestions.

People vary in hypnotizability. Hypnotic amnesia is a recent

phenomenon induced by expectations.• Amnesia was not part of hypnosis until 20th

century.

Early Hypnotists

Mesmer (1779)

Inducing Hypnosis

Accuracy of Hypnotic Recall

People report more memories while hypnotized, but are less accurate.• The increased info may be no different than

what occurs with repeated questioning without hypnosis.

Along with more information, more intrusions (false info).• Hypnotized subjects are more easily fooled.

Everyday False Memories

Verbal overshadowing – memories change as we talk about them.• 64% recalled robber without narrative, 38%

percent with narrative Revelation effect – slowly revealed info

can cause new info to be judged as old.• Slow revelation generates familiarity

• A lengthy memory recovery process can add a sense of familiarity to what is described.