A Modular Approach to STM

• Allan Baddeley:

Articulatory Loop

Central Executive

Visuospatial Sketchpad

The article by Lee Brooks considers a double-dissociation between Phonological and Visuospatial memory representations

Coding in STM

• Evidence for a modular system:– interference within modalities but not between– example: subvocal counting of letters in a list of words is very hard but subvocal counting of the

corners of a figure is easy

Working Memory “Modules”

• Lee Brooks: interference between different representations in STM (Experiment 1)– Memory Representation

• verbal task: categorize words in a sentence

• spatial task: categorize corners in a block letter

– Response Modality• verbal response: say “yes” or “no”

• spatial response: point to “yes” or “no”

Working Memory “Modules”

• result:

Response Time

Response Modality

Verbal Spatial

Spatial Representation(categorize corners)

Verbal Representation(categorize nouns)

Working Memory “Modules”

• Interpretation:– supports notion of modularity in Working Memory (visuospatial sketchpad / articulatory loop)

Long-Term Memory

See Cognition textbook on reserve for review

Model of Memory

We’ve discussed STM

Sensory Signals

Sensory Memory

Short-Term Memory

Long-Term Memory

ATTENTION

REHEARSAL

RETRIEVAL

Some Things to Consider Re: STM

• Short-Term Memory

– decays rapidly (within seconds) unless…

– requires active process or cognitive engagement to maintain

But surely there must be another way to maintain information !?

Model of Memory

Turning now to Long-Term Memory

Sensory Signals

Sensory Memory

Short-Term Memory

Long-Term Memory

ATTENTION

REHEARSAL

RETRIEVAL

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)

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)

– What are some examples of Long-Term Memories?

Some Distinctions in LTM

• Endel Tulving: There are two broad categories of information that are represented in LTM -

• Examples:– What did you eat for breakfast?– What is the capital of Canada– Where were you when…– Are maple trees deciduous?– Riding a bike !?

Some Distinctions in LTM

• Endel Tulving: There are two broad categories of information that are represented in LTM -

• 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

• Endel Tulving: There are two broad categories of information that are represented in LTM -

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

• unconnected to an autobiographical event

• no temporal context

Some Distinctions in LTM

• A third category may be distinguished:– Example: riding a bike, playing an instrument

Some Distinctions in LTM

• A third category may be distinguished:

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 fap) 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– Evidence: Semantic Priming in a Lexical-Decision

Task– 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

Semantic Memory

• Structure of encoding is associative– Example: Accessing a memory that is “on the

tip of your tongue”• you’re trying to rent a movie but you can’t recall the

title of the one you have in mind, you scan through the associated facts: the actors, the plot, the setting, etc. until the title surfaces

• each recalled piece of knowledge “activates” related knowledge until the title is sufficiently activated

Semantic Memory

• Structure of encoding is associative– This idea is formalized in so-called

“connectionist” networks

birdcanary

chicken

mockingbird

To Kill A Mockingbird

racism

highschool

Martin Luther King

hockey

Mr. Cassella

physics

When You Don’t Remember

• Two reasons why you don’t remember semantic information:

When You Don’t Remember

• Two reasons why you don’t remember semantic information:

• Unavailable– It wasn’t successfully encoded - something when wrong while you were

studying

When You Don’t Remember

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

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

• Inaccessible– memory is stored but cannot be retrieved, perhaps because appropriate connections aren’t being made

When You Don’t Remember

• Two reasons why you don’t remember semantic information:

• context is critical!– e.g. lists of words are recalled better when recalled where they were first

learned

Next Time

• Episodic Memory• Read Loftus for Monday• Read Sacks for Wednesday