Model of Memory

Turning now to Long-Term Memory

Sensory Signals

Sensory Memory

Short-Term Memory

Long-Term Memory

ATTENTION

REHEARSAL

RETRIEVAL

Distinctions in LTM

• Let’s review the major distinctions made in describing aspects of LTM

Distinctions in LTM

• Let’s review the major distinctions made in describing aspects of LTM

• What is “Declarative Memory”

Distinctions in LTM

• Let’s review the major distinctions made in describing aspects of LTM

• What is “Declarative Memory”• Memory you can talk about• Conscious access• Includes semantic and episodic memory

Distinctions in LTM

• Let’s review the major distinctions made in describing aspects of LTM

• What is “Semantic Memory”

Distinctions in LTM

• Let’s review the major distinctions made in describing aspects of LTM

• What is “Semantic Memory”• Memory for facts, knowledge

Distinctions in LTM

• Let’s review the major distinctions made in describing aspects of LTM

• What is “Episodic Memory”

Distinctions in LTM

• Let’s review the major distinctions made in describing aspects of LTM

• What is “Episodic Memory”– Biographical– Episodes of your life– Has a temporal context

Distinctions in LTM

• Let’s review the major distinctions made in describing aspects of LTM

• What is “Procedural Memory”

Distinctions in LTM

• Let’s review the major distinctions made in describing aspects of LTM

• What is “Procedural Memory”• How to do things• “non-declarative” …you don’t have to describe

what you’re doing to yourself as you do it

Distinctions in LTM

• Let’s review the major distinctions made in describing aspects of LTM

• What is encoding?

Distinctions in LTM

• Let’s review the major distinctions made in describing aspects of LTM

• What is encoding?• Storing information associated with an event or

a fact• Linking that information to associated items in

memory

Distinctions in LTM

• Let’s review the major distinctions made in describing aspects of LTM

• What is retrieval?• Recall• Reconstructing aspects of an event (i.e. not like

video playback)• Reactivating the links associated during

encoding

Distinctions in LTM

• Let’s review the major distinctions made in describing aspects of LTM

• What is the distinction between “implicit” and “explicit”

Distinctions in LTM

• Let’s review the major distinctions made in describing aspects of LTM

• What is the distinction between “implicit” and “explicit”– Implicit memories don’t enter the contents

of awareness– Explicit memories can enter into the

contents of awareness

Distinctions in LTM

• Let’s review the major distinctions made in describing aspects of LTM

• What is the distinction between “unavailable” and “inaccessible”

Distinctions in LTM

• Let’s review the major distinctions made in describing aspects of LTM

• What is the distinction between “unavailable” and “inaccessible”

• Unavailable memories are not encoded in the brain…either lost or never encoded

• “inaccessible” memories are encoded but cannot be retrieved (e.g. repressed memory)

Distinctions in LTM

• Let’s review the major distinctions made in describing aspects of LTM

• What is the “misinformation effect”?

Distinctions in LTM

• Let’s review the major distinctions made in describing aspects of LTM

• What is the “misinformation effect”?• Inaccuracies can be introduced to episodic

memories when they are retrieved

Repressed Memories

• What is Loftus’ main concern about DE-repressed memories?

Repressed Memories

• What is Loftus’ main concern about DE-repressed memories?– Memory may be inaccurate– Confidence in memory may be inaccurate– Hard to know accuracy despite a vivid

episodic memory

Modular memory systems

• We saw evidence that working memory is modular– Visuospatial sketchpad– Articulatory loop

Modular memory systems

• Are long-term memories also modular?

Modular memory systems

• Are long-term memories also modular?

• Yes – best evidence is from patients with brain injury– dissociations

Modular memory systems

• Damage to the Hippocampus leads to amnesia– Specifically episodic memory

Modular memory systems

• Damage to the Hippocampus leads to amnesia– Specifically episodic memory

– Often severe anterograde amnesia• Can’t encode new memories

Modular memory systems

• Damage to the Hippocampus leads to amnesia– Specifically episodic memory

– Often severe anterograde amnesia• Can’t encode new memories

– Often some degree of retrograde amnesia• Can’t retrieve old memories

Modular memory systems

• Damage to the Hippocampus leads to amnesia– Hippocampal-dependent amnesia

dissociates declarative episodic memory from other kinds of memory• Intact procedural memories• Intact semantic memories• Intact implicit memory

Long-Term Memory

• Characteristics (intuitive with some introspection):

– Persists indefinitely (up to decades!)

– Requires no active process of rehearsal (at least that we are conscious of)

Some Distinctions in LTM

• Declarative/Non-Declarative• Declarative memory is for the sort of information

that can become explicit – facts (semantic), autobiographical events (episodic)

• The term explicit memory is often associated to convey that such memories are accesible to conscious awareness

Some Distinctions in LTM

• Declarative/Non-Declarative• Non-declarative memory is for the sort of

information that is used without explicit awareness – how to do an action (procedural)

• The term implicit memory is often associated to convey that such memories affect behaviour without awareness

Some Distinctions in LTM

• Declarative Memory:

• Episodic Memory: memory of an event in your life

• autobiographical• has a temporal context - something about time

is encoded along with the memory

Some Distinctions in LTM

• Declarative Memory:

• Semantic Memory: memory of facts, knowledge of the world

• unconnected to an autobiographical event• no temporal context

Some Distinctions in LTM

• Procedural Memory: memory for actions

Semantic Memory

• Capacity is huge (unlimited?)

Semantic Memory

• Structure of encoding is associative

Semantic Memory

• Structure of encoding is associative– Evidence: Semantic Priming in a Lexical-

Decision Task

• Priming: prior exposure to some stimulus modifies subsequent processing of a target

Semantic Memory

• Structure of encoding is associative– Evidence: Semantic Priming in a Lexical-

Decision Task

• Lexical Decision Task: Subject is shown a target word or pronounceable non-word (eg. gap or bap) and must respond “word” or “non-word”

Semantic Memory

• Structure of encoding is associative– Evidence: Semantic Priming in a Lexical-

Decision Task

• manipulation: prime can be either related or unrelated to the target word

Semantic Memory

• Structure of encoding is associative– Evidence: Semantic Priming in a Lexical-

Decision Task

• result: words are identified faster when preceded by a semantically related prime

Prime + Target = Response“space” “gap” fast“truck” “gap” slow

Semantic Memory

• Structure of encoding is associative– Other evidence: memory can be triggered

by recalling related facts

Semantic Memory

• Structure of encoding is associative– Interpretation:

• the representation of information in semantic memory is associative:

• each fact or piece of knowledge is stored along with its relationship to other stored information

• related items can activate each other which facilitates recall

Episodic Memory

• Memory for an episode or event in your own life

• Has temporal context (entails a sense of duration and date)

• examples:– recall breakfast– what happened this weekend

Recalling Episodic Memory

• Recall is highly sensitive to context - Similarities in context (especially smell) can trigger vivid recollections

Recalling Episodic Memory

• Memory is affected by the nature of your engagement with the information

• Levels-of-Processing Theory

Recalling Episodic Memory

• Memory is affected by the nature of your engagement with the information

• Levels-of-Processing Theory– Consider this experiment:

ListCATpiePILLOWTREE

Method of Learning• stating capitals or lower-case• repeating words• putting words into a sentence

Recall is tested some time later.

Recalling Episodic Memory

• Memory is affected by the nature of your engagement with the information

• Levels-of-Processing Theory– Consider this experiment:

Result:• Best recall with “deep”

processing• Worst recall with “surface”

processing

ListCATpiePILLOWTREE

Recalling Episodic Memory

• Memory is affected by the nature of your engagement with the information

• Interpretation:

– the successful use of memory depends on the number of connections that are made between related items and the degree to which these are initially activated

Hypermnesia - S.

• “Photographic” extreme memory ability (a mnemonist)

• Able to recall complex test stimuli

Hypermnesia - S.

• S. used two “strategies” or abilities typical of mnemonists:– Rich synesthesia-like quality to his

perception of stimuli - leads to stronger associative links

Hypermnesia - S.

• S. used two “strategies” or abilities typical of mnemonists:– Rich synesthesia-like quality to his

perception of stimuli - leads to stronger associative links

– Vivid and elaborate mental imagery of things he should remember

Hypermnesia - S.

• “ Even numbers remind me of images. Take the number 1. This is a proud, well-built man; 2 is a high-spirited woman; 3 a gloomy person (shy, I don’t Know); 6 a man with a swollen foot...”

Luria, A.R. The mind of a mnemonist. 1968

Luria, A.R. The man with a shattered world. 1972

When You Don’t Remember

• Two reasons why you don’t remember:

When You Don’t Remember

• Two reasons why you don’t remember:• Unavailable

– It wasn’t successfully encoded - something went wrong while you were studying

When You Don’t Remember

• Two reasons why you don’t remember:• Unavailable

– It wasn’t successfully encoded - something went wrong while you were studying

• Inaccessible– memory is stored but cannot be retrieved,

perhaps because appropriate connections aren’t being made

Implicit and Explicit Memory

• Are all memories explicit? Is all information stored in the brain subject to conscious scrutiny?

Implicit and Explicit Memory

• Are all memories explicit? Is all information stored in the brain subject to conscious scrutiny?

• Implicit Memory refers to encoded memories that are not part of the “contents” of awareness

Implicit and Explicit Memory

• How can we know whether memory is stored/recalled implicitly or explicitly?

Implicit Memory

• Consider the following distinction in recalling items from a list of words:

Implicit Memory

• Consider the following distinction in recalling items from a list of words:

• Free Recall - subjects can be asked to simply recall and report as many items as possible - these items are accessible as explicit memory

Implicit Memory

• Consider the following distinction in recalling items from a list of words:

• Implicit Recall - subjects can be asked to complete a word stem with any word that comes to mind after reading a list of words (no mention of testing memory!)

__ack

Implicit Memory

• Consider the following distinction in recalling items from a list of words:

• Implicit Recall - subjects can be asked to complete a word stem with any word that comes to mind after reading a list of words (no mention of testing memory!)

But how do you know that information is stored/recalled implicitly? Couldn’t it be explicit?

Implicit Memory

• Consider the following distinction in recalling items from a list of words:

• Twist - require subject to complete stem with a word that wasn’t on the list - if a word from the list is used preferentially, it was remembered implicitly

Implicit Memory

Consider the implications regarding the nature of consciousness and the connection between neural activity and awareness

Implicit Memory

Consider the implications regarding the nature of consciousness and the connection between neural activity and awareness

Not all of the activity in your brain generates experience - some is “sub”conscious or non-conscious

Recalling Episodic Memory

• Recall is a generative processes rather than simply calling up stored data

Recalling Episodic Memory

• Recall is a generative processes rather than simply calling up stored data

• Evidenced by the fact that episodic memories can be distorted or completely false under certain circumstances

Recalling Episodic Memory

• Misinformation Effect - exposure to information subsequent to storage of memory can alter the contents of the memory

Recalling Episodic Memory

• Misinformation Effect • Consider the following example:

– Subjects were shown a video depicting a car accident

Recalling Episodic Memory

• Misinformation Effect • Consider the following example:

– Subjects were shown a video depicting a car accident

– Then given the following question: “How fast were the vehicles going when they ______”

Recalling Episodic Memory

• Misinformation Effect • Consider the following example:

– Subjects were shown a video depicting a car accident

– Then given the following question: “How fast were the vehicles going when they ______”

– Different subjects were asked questions that differed in the “magnitude” of the final word

Recalling Episodic Memory

• Misinformation Effect • Consider the following example:

– Subjects were shown a video depicting a car accident

– Then given the following question: “How fast were the vehicles going when they ______”

– Different subjects were asked questions that differed in the “magnitude” of the final word

– The possible words were: Contacted, Hit, Bumped, Collided, and Smashed

Recalling Episodic Memory

• Misinformation Effect • Consider the following example:

– Average estimated velocity depended on the nature of the question

Recalling Episodic Memory

• Misinformation Effect • Interpretation:

– Episodic memory can be distorted by subsequent information

Recalling Episodic Memory

• Memory for episodes in life can be illusory

Recalling Episodic Memory

• Memory for episodes in life can be illusory

• Consider the example in Loftus’ article:– participant was induced to have an episodic

memory of being lost in a mall

Recalling Episodic Memory

• Memory for episodes in life can be illusory

• Consider the example in Loftus’ article:– participant was induced to have an episodic

memory of being lost in a mall– Even when told the memory is a false one, the

participant had difficulty recognizing it as an invalid memory

Recalling Episodic Memory

• False Memories may arise when details of a crime are in question as in eye-witness testimony or repressed memories of abuse during childhood

Repressed Memories

Elizabeth Loftus

“Derepressed memories”

• Loftus opens with several examples of court cases that involve “derepressed memories”

• What is a repressed memory?• What is a derepressed memory?

Loftus’ position in this article

• Loftus does not reject the notion of repressed memories– 18% - 59% of abuse survivors report

having regained access to previously repressed memories

Loftus’ position in this article

• Loftus does not reject the notion of repressed memories– 18% - 59% of abuse survivors report

having regained access to previously repressed memories

• What does Loftus challenge?

Loftus’ position in this article

• Loftus does not reject the notion of repressed memories– 18% - 59% of abuse survivors report

having regained access to previously repressed memories

• What does Loftus challenge?

…That all “de-repressed” memories are accurate memories.

High Stakes

• Survivor of real abuse might struggle for years or decades with consequences and need to confront the repressed memory in order to recover emotionally

• False accusation could tear family apart and send an innocent person to jail

What’s the issue?• What does Loftus express concern about regarding

the derepression of memories?

What’s the issue?• What does Loftus express concern about regarding

the derepression of memories?– reality of the memory is in question if it is recalled under

certain circumstances

What’s the issue?• What does Loftus express concern about regarding

the derepression of memories?– reality of the memory is in question if it is recalled under

certain circumstances• What is the course of events that Loftus finds

worrisome?

What’s the issue?• What does Loftus express concern about regarding

the derepression of memories?– reality of the memory is in question if it is recalled under

certain circumstances• What is the course of events that Loftus finds

worrisome?

Therapist or Popular Book suggests that patient consider possibility of abuse

Patient engages in intense effort to recall

An explicit episodic memory is achieved

This memory might be false!

What’s the issue?

• So we potentially have a situation in which someone who is having troubles in life and is seeking answers is told to determine whether or not memories for abuse exist

• What are some techniques that are used to “assist” recollection?

What’s the issue?

• So we potentially have a situation in which someone who is having troubles in life and is seeking answers is told to determine whether or not memories for abuse exist

• What are some techniques that are used to “assist” recollection?– hypnosis, imagery, dream analysis, story telling– Loftus presents evidence that such processes may

lead to invalid memories or overconfidence in the validity of memories

Conclusion:• We cannot know with certainty (without corroborating

evidence) whether a derepressed memory is true• Therapists should engage in probing this possibility

very carefully– avoiding suggestive questions– remaining unconvinced without corroborating

evidence– being “gently confrontational” to encourage patient

to consider the possibility that the events didn’t happen