Schacter

7 Sins of Memory

• Transience—loss with time

• Absent mindedness

• Blocking—retrieval failures

• Misattribution—source errors

• Suggestibility

• Bias

• Persistence

Transience

• Forgetting over time: decay? Interference?

• Decay: see articles about mouse brain and about juggling and brain changes

• Interference: more similar events “run together”

Transience

• Ebbinghaus forgetting curve

• Diary studies—similar, but less forgetting

Transience

• Write down what you did 2 weeks ago today

• Write down what you did yesterday

• Write down what you did last Thanksgiving

Transience

• Aging—faster loss of information

• Older people—rely more on general memory of what happened; recall fewer specifics

• More education, continued brain activity helps preserve memory in old age

Transience

• Brain damage studies: hippocampus and frontal lobe

• HM—had inner parts of both temporal lobes removed (including hippocampus)

• HM could not form new memories

Transience

• fMRI—can indicate which words most likely to be remembered (ones accompanied by most lower left frontal lobe activation)

• Left frontal lobe—used for elaboration, meaningful processing

• Similar study for pictures—right frontal lobe involved instead of left

Transience

• Working memory

• Phonological loop—normally fades quickly

• KF—brain damage back part of parietal lobe

• KF had impaired phonological loop, but still could form long term memories

Transience

• Phonological loop—needed to learn new vocabulary

Transience

• Narratives and memory—talking about experiences makes them memorable

• Study with children—trip to a museum (not in this book)

Transience

• Are memories “gone” or is it just “cue-dependent forgetting?”

• Both!

• Relate to: Rovee-Collier studies with infants; PDP model

• Studies: Wagenaar self study—with enough cues, usually could remember

Transience

• Mnemonics: usually too much work to use on a daily basis

• Noice & Noice: study of actors; implications for us

• Foods, herbals, etc. and memory: must separate specific effects on memory from general arousal effects and such

Transience

• Genetics—probably some genetic reasons for individual differences in memory

• Mice—engineered to have better memory by gene change for NMDA receptor activity

• Smart drugs or smart genes ?

Absent mindedness

• Recollection vs. familiarity

• Divided attention decreases recollection, but not familiarity

• Divided attention decreases lower left frontal lobe activity, lowers memory

• Automaticity

• Massed vs. spaced practice effects

Absent mindedness

• Change blindness—see demos:djs_lab demos

Absent mindedness

• Prospective memory—remembering to do something in future

• Event-based: to do something when some event occurs

• Time-based: to do something at a specific time in future

Absent mindedness

• Time based is harder than event based; good strategy is to change time to event based

Blocking

• Most commonly with people’s names

• “names not connotative” John Stuart Mill

• Theory: common names—several conceptual links to lexical representation

• Proper names—conceptual link to “person identity node” which then links to lexical representation

Blocking

• Argument is that several links are better than just one link

• Additional factors: common names have synonyms, and common objects can be described at different levels

Blocking

• Proper name anomia—left frontal lobe, especially temporal pole area

• Common names farther back in temporal lobe

• Can lose names or names + places (but never just places)

Blocking

• Tip of the Tongue (TOT)

• “ugly sisters theory”—intrusive word retrieval interferes with target retrieval

• Not well-supported: giving similar sounding words doesn’t make it worse; targets with many phonological neighbors not more of a problem

Blocking

• Best explanation: weakened connection to lexical representation can’t quite activate phonological representation; weakened due to long time since encountered

Blocking

• Incubation? Probably not due to unconscious ongoing retrieval process

• Incubation probably due to retrieval cues from experience of thought processes

Blocking

• Repression? Some evidence for directed forgetting

• Retrieval inhibition apparently can occur• New neurological studies may elucidate

eventually• Individual differences: some people are

“repressors”—good at shutting down memories of some things

Misattribution

• Déjà vu—a misattribution of current experience to past

• Misattribution also called “source error”

• Bystanders at crime risk being identified by eyewitnesses as perpetrator

• Memory binding—connecting parts of experience into unitary whole

Misattribution

• Binding failures can cause misattributions, as events, place, actors, time confused

• Imagining an event can create misattributions—attribute memory to actual experience instead of imagination

• Older people encode more generally (fewer specifics) which yields more misattributions

Misattribution

• Memory conjunction error—combine different stimuli (words, faces) into one

• Hippocampus involved in binding process, based on brain injuries, fMRI studies

Misattribution

• Familiarity—if stimulus judged to be familiar, may misattribute source of that familiarity

• Eyewitnesses, lineups, mug shots—if have seen picture of person, may cause familiarity that is misattributed to crime scene

Misattribution

• “Truth machine?”—PET scans show different brain activation for new vs. old stimuli

• But: may have been artifact of experimental design; ERP study did not support

• “Brain fingerprinting?” (Farwell)--doubts

Misattribution

• Brain activity does differ when retrieving specific vs. general memories

• Some people make more misattributions than others; may relate to specificity of their recall and how much they base decision on specific recall vs. familiarity

• Distinctiveness heuristic—if told to say “old” only when recall specifics, fewer errors

Misattribution

• Misattribution disorders: seeing film stars everywhere

• Damage to frontal lobes—problems with monitoring source, problems with “person identity node” processing

• “face recognition unit”??—recent studies not sure; may be highly familiar unit

Misattribution

• Fregoli delusion—very specific false memories, e.g., that a stranger is “inhabited” by friend or famous person

• Frontal lobe monitoring systems faulty

• Cryptomnesia—something old perceived as new; unconscious plagiarism (“How do I love thee? Let me count the ways”)

Suggestibility

• Loftus studies—eyewitnesses & misleading post-event questions

• Confidence of new memories not predictive of their accuracy

• Even recent memories can be affected by misleading post-event information

• Telling Ss doesn’t stop it from happening

Suggestibility

• Lineup procedure—confirming feedback makes eyewitness confident; juries convinced by confident testimony

• Telling Ss to ignore information does not work—e.g., Judge: “The jury will ignore what the witness just said.”

Suggestibility

• Hypnosis—easy to create incorrect, but confidently held memories

• Cognitive interview: leads to better recall with less increase in wrong memories

• Elements of C.I.: 1. Free recall 2. Reinstate context 3. Try different temporal order 4. Try different perspectives

Suggestibility

• False confessions—due to coercion, attention seeking, or spontaneous misattributions

• Memory distrust syndrome—if don’t trust own memory monitoring, easier to believe you did things imagined or suggested

• Interrogative suggestibility—some people very susceptible to such problems

Suggestibility

• Kassin’s study: student’s convinced by E they had hit ALT key, when hadn’t, if witness told them they had

• Thus, under certain conditions, many of us can have memories suggested to us

Suggestibility

• False memory syndrome—e.g., recovered memories of child abuse

• Usually memories “recovered” during therapy; some therapists use highly suggestive techniques

• Some things recalled quite hard to believe—e.g., satanic ritual abuse memories

Suggestibility

• Lab studies demonstrate ease of creating false memories

• Loftus—lost in the mall studies

• Spanos—infant memories (day of birth) suggested & subjects “retrieved”

• Imagery—if can get Ss to imagine it, some will confuse as actual memory

Suggestibility

• Dream interpretation—can create false memories

• Individual differences—high score on Gudjonsson interrogative suggestibility scale: more false memories

• Some people still in prison due to apparent false memories created by interviewers—Amirault, Wenatchee

Bias

• 5 types: consistency, change, hindsight, egocentric, & stereotypical biases

• Consistency bias—alter memories of how we previously felt & thought to be more consistent with current feelings & thoughts

• “implicit theory of stability”—belief that our beliefs have not changed over time

Bias

• Change bias—belief that our feelings & thoughts have changed over time, more than they actually have

• More likely than consistency bias when we believe they SHOULD HAVE changed

• E.g.: PMS study—real-time data show no correlation between emotions & cycle; memories for emotions are correlated

Bias

• Consistency & change biases together—relationships over time

• Either can lead to positive or negative results

• If relationship sours, consistency bias may lead to believing it always was bad

• If relationship hasn’t actually changed, positive change bias makes happier

Bias

• Combination found for happy long-term relationships: positive change bias as relationship declines in happiness (honeymoon is over), followed by consistency bias if happiness actually declines (real-time ratings)

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Actual

Memory

Bias

• Consistency & change biases help reduce cognitive dissonance

Bias

• Hindsight bias—I knew it all along!• Measure prediction & confidence in it• Once outcome known, tendency to

remember having thought that would happen

• If remember actual prediction correctly, still tend to change confidence level in line with new knowledge

Bias

• Hindsight bias a problem in trials, as warning people not to let new information affect their opinion does not work

Bias

• Egocentric bias—tend to trust our own memories more than those of others, partly due to awareness of vividness of own memories

• People think they were more responsible for events than they were, even for negative events

Bias

• Positive illusions—more positive view of self than justified; maybe is good for us; does distort memory due to egocentric bias

• Sometimes exaggerate negativity of earlier situation to make improvement seem greater (“deprecate past selves … for more favorable view of present self”)

Bias

• Stereotypical bias—tend to more easily remember info that is consistent with a stereotype

• Can create self-perpetuating cycle: bias—selective memory—support for bias—etc.

Bias

• Left-brain, right-brain & bias: right brain remembers rather accurately, in rote fashion, what was perceived; left brain explains & interprets

• Thus, left brain source of bias

• But, if only had right brain memory, would be less comprehending

Persistence

• Arousal—can make memories stronger, but mainly for emotion-arousing stimulus (other aspects remembered less well)

• Some evidence negative memories fade faster than positive

• Dilemma—talk about bad memories or avoid them? May be individual difference

Persistence

• Some people ruminate excessively about negative events; can prevent recovery

• Women tend to be more ruminating than men; women have more depression problems than men; coincidence??

• Solution may be to disclose to others (confession?); various studies support

Persistence

• PTSD—trying too hard to avoid thinking about in short run may make long-term fixation greater (rebound effect)

• But, recent studies don’t support forced counseling for students when classmate dies