A Modular Approach to STM
• Allan Baddeley:
Central
Executive
Articulatory
Loop
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:
Spatial Representation
(categorize corners)
Response
Time
Verbal Representation
(categorize nouns)
Verbal
Spatial
Response Modality
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
RETRIEVAL
ATTENTION
Sensory
Signals
Sensory
Memory
Short-Term
Memory
Long-Term
Memory
REHEARSAL
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
RETRIEVAL
Turning now to Long-Term Memory
ATTENTION
Sensory
Signals
Sensory
Memory
Short-Term
Memory
Long-Term
Memory
REHEARSAL
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 LexicalDecision 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 LexicalDecision 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 LexicalDecision 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 LexicalDecision Task
• result: words are identified faster when preceded by
a semantically related prime
Prime
“space”
“truck”
Target
“gap”
“gap”
Response
fast
slow
Semantic Memory
• Structure of encoding is associative
– Evidence: Semantic Priming in a LexicalDecision 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
hockey
highschool
mockingbird
bird
canary
chicken
Mr. Cassella
To Kill A Mockingbird
racism
physics
Martin Luther King
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