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Memory continued

July 15, 2013

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Review

Memory is a three-stage process

Sensory Memory

Short-Term Memory Long-Term Memory

What we remember is limited by capacity,

attention, and rehearsal

Memory is reconstructive

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Encoding Specificity

Learning and remembering is often dependent

on our environment mirroring the one we learned

in Context-Dependent Learning

You are more likely to remember information in the

same location you first learned it

State-Dependent Learning

You are more likely to remember information if your

body is in the same physiological condition as it was

when you first learned

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Other Errors in Recall

Retrospective Bias

Current mood, state, and environment can affect

how we interpret or reconstruct past events

Tip-of-the-Tongue Phenomenon

Normal and common

May be increased by proactive interference

Often aided by retrieval cues

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The Biology of Memory

Review of crucial structures

Hippocampus

Limbic System

Memory is not located in any one portion of the

brain one of the most diffuse, complex functions

we exhibit

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Historical Perspective

Karl Lashley (1940s)

Wanted to find the engram (the picture) of the

memory in the brain Didnt find an engram at all

Memories are not located in one specific region

Donald Hebb (1950s)

Cell Assembly: a web of interconnected neurons that

tend to fire together

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Long-Term Potentiation

Largely a confirmation ofHebbs theory

Neurons that fire together, wire together

LTP is the strengthening of synaptic connections

and the creation of new synapses between

neurons that repeatedly fire together

Especially common at glutamatergic synapses in

hippocampal and limbic structures

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How LTP works

More spines on dendrites

Spines get shorter and squatter to facilitate AP

transmission

More receptors on spines

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Memory Deficits

What is amnesia?

Loss of memory function

Not often complete (generalized amnesia) Recovery occurs often, but gradually

Much of what we know about normal memory

processes comes from people with amnesia

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Retrograde Amnesia

Cannot remember previously known information

Does not affect procedural or implicit memories

Likely governed by different structures / more spread

out

Can still drive a car, play piano, cook, etc.

Almost always affects moments before injury

Consolidation from short-term to long-term memoryinterrupted by the injury

Longer-term memories usually recovered

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Anterograde Amnesia

Cannot form new memories following injury

May or may not return

Does not affect procedural or implicit memory You can learn to perform a new skill following the

accident and perform it perfectly, but not remember

ever having learned it

Could be linked to damage to limbic system:

no emotional response to stimulus = no memory of it

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Amnesia Case Study:

H.M. Suffered from severe epilepsy

Temporal lobes removed bilaterally to ease

seizures

Left with near-complete anterograde amnesia

Clive Wearing

http://www.youtube.com/watch?v=Vwigmktix2Y

http://www.youtube.com/watch?v=Vwigmktix2Yhttp://www.youtube.com/watch?v=Vwigmktix2Y

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Emotion and Memory

The amygdala plays a key role in remembering

emotionally charged events

If you cannot emotionally react to a situation, you

are less likely to remember it

Injuries to the limbic system especially the

amygdala can lead to anterograde amnesia

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Memory Development

Adults cannot recall memories from earlychildhood (infantile amnesia)

Memory span increases with age (biological

maturity)

Conceptual understanding matures with age

Allows for relating items together by concept, chunkitems, etc.

Children develop meta-memory: knowledge oftheir own memories and skills

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False Memories

Flashbulb Memories

Vivid, seemingly unfading memories of emotional

events

When tested, these memories evolve and changeover time

Where were you when

You heard about 9/11?

You heard Osama bin Laden was killed?

If you had a videotape of yourself on these days,

how accurate would your memory be?

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Misinformation Effect

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Eyewitness Testimony

Eyewitnesses tend to be inaccurate because

They are more focused on the weapon than the person

holding it

They only see the culprit for a short period of time, often

disguised or in motion

There is a long latency between the witnessed event and

their testimony

People fall victim to the representative heuristic, the

availability heuristic, and demand characteristics oflineups

http://www.youtube.com/watch?v=nLGXrviy5Iw

http://www.youtube.com/watch?v=nLGXrviy5Iwhttp://www.youtube.com/watch?v=nLGXrviy5Iw

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Recovered Memories

Children are very sensitive to other peoples

reactions to their behavior, and thus prone to

suggestion

Therapists need to use non-leading questions andnot shape responses through their reactions to

particular answers

Adults will seek order; when they experience

emotions with no known root they will seek

answers

Most cases of recovered memories of abuse

have been proven false

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The 7 Sins of Memory

Suggestibility

We will incorporate suggestion into memories to forminaccurate composites

Misattribution We can attribute memories to incorrect sources or

imaginary sources

Bias

Stereotypes, cognitive biases, expectations

Transience

Time between memory and recall decreasesaccuracy

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The 7 Sins of Memory

Persistence

Negative events tend to persist longer in our

memories than positive ones

Blocking

Tip-of-the-tongue phenomenon, temporary forgetting

of what you were saying or thinking

Absentmindedness

Failure in encoding or retrieval

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Miscellaneous Memory Videos

Hyperthymesia:

http://www.youtube.com/watch?v=B-uFDhJPKOc

Eidetic Memory:http://www.youtube.com/watch?v=x3IMP0fwlCM

False Memories:

http://www.youtube.com/watch?v=rIRaw5z62Jk

http://www.youtube.com/watch?v=B-uFDhJPKOchttp://www.youtube.com/watch?v=x3IMP0fwlCMhttp://www.youtube.com/watch?v=rIRaw5z62Jkhttp://www.youtube.com/watch?v=rIRaw5z62Jkhttp://www.youtube.com/watch?v=rIRaw5z62Jkhttp://www.youtube.com/watch?v=x3IMP0fwlCMhttp://www.youtube.com/watch?v=B-uFDhJPKOchttp://www.youtube.com/watch?v=B-uFDhJPKOchttp://www.youtube.com/watch?v=B-uFDhJPKOc