Read:
Sacks for Thursday
Loftus for Tuesday
Vokey for Thursday
Iconic Memory
• a brief storage of “raw data” in the visual
system
Echoic Memory
• Auditory information is stored in a
similar sensory “buffer”
– Echoic memory seems to last for several
seconds
Properties of Sensory Memory
1. Brief (iconic ~500ms; echoic ~2
seconds)
Properties of Sensory Memory
1. Brief (iconic ~500ms; echoic ~2
seconds)
2. Virtually unlimited capacity
Properties of Sensory Memory
1. Brief (iconic ~500ms; echoic ~2
seconds)
2. Virtually unlimited capacity
3. pre-attentive
Overview of Memory
RETRIEVAL
• Atkinson-Shiffrin Model
ATTENTION
Sensory
Signals
Sensory
Memory
Short-Term
Memory
Long-Term
Memory
REHEARSAL
Short-Term Memory
• process by which we hold information
“in mind”
Short-Term Memory
• process by which we hold information
“in mind”
• example: temporarily remembering a
phone number
Characteristics of STM
•
Duration? Capacity?
•
How could one measure these
parameters?
Characteristics of STM
•
Limited Duration
– Brown-Petersen Task:
• subject is given a trigram (e.g. C-F-W)
to remember
• vocal rehearsal is prevented by
counting backwards
• recall accuracy tested as a function of
retention interval
Characteristics of STM
•
STM
decays
over
seconds
Characteristics of STM
•
Limited Duration
– Brown-Petersen Task Interpretation: rapid
loss of information in STM (over a period
of seconds…much longer than sensory
memory)
Characteristics of STM
•
Limited Capacity
– How might you measure capacity?
Characteristics of STM
•
Limited Capacity
– George Miller
– Subject is given longer and longer lists of
to-be-remembered items (words,
characters, digits)
Characteristics of STM
•
Limited Capacity
– George Miller
– Subject is given longer and longer lists of
to-be-remembered items (words,
characters, digits)
– Result: Subjects are successful up to
about 7 items
Characteristics of STM
•
Limited Capacity
– What confound must be considered ?!
Characteristics of STM
•
Limited Capacity
– What confound must be considered ?!
– Recalling takes time !
Characteristics of STM
•
Limited Capacity
– What confound must be considered ?!
– Recalling takes time !
– It seems that the “capacity” of STM (at
least measured in this way) depends on
the rate of speech - faster speech leads
to apparently larger capacity
– Some believe capacity is “2 - 3 seconds
worth of speech”
Forgetting from STM
• Why do we “forget” from STM?
– Does the memory trace decay?
• not likely because with very small lists (like 1
item) retention is high for long intervals
Forgetting from STM
• Why do we “forget” from STM?
– Does the memory trace decay?
• not likely because with very small lists (like 1
item) retention is high for long intervals
– Instead, it seems that information “piles up”
and begins to interfere
Forgetting from STM
• Interference in STM is complex and
specific
Forgetting from STM
• Interference in STM is complex and
specific
• For example, severity of interference
depends on meaning
Forgetting from STM
• Interference in STM is complex and
specific
• For example, severity of interference
depends on meaning
– Subjects are given successive recall tasks
with list items from the same category (e.g.
fruits)
– final list is of either same or different
category - how is good is recall on this list?
Forgetting from STM
• Accuracy rebounds if category changes
Coding in STM
• How is information coded in STM?
Coding in STM
• Clues about coding in STM:
– # of items stored in STM depends on rate
of speech
Coding in STM
• Clues about coding in STM:
– # of items stored in STM depends on rate
of speech
– phonological similarity effect: similar
sounding words are harder to store/recall
than different sounding words
Coding in STM
• Clues about coding in STM:
– # of items stored in STM depends on rate
of speech
– phonological similarity effect: similar
sounding words are harder to store/recall
than different sounding words
What does this suggest about the nature of information in STM?
Coding in STM
• It seems that information can be stored
in a linguistic or phonological form
Coding in STM
• It seems that information can be stored
in a linguistic or phonological form
Must it be stored this way?
Coding in STM
• It is also possible to “keep in mind” nonverbal information, such as a map
Are there two different STM systems?
A Modular Approach to STM
Central
Executive
Articulatory
Loop
Visuospatial
Sketchpad
Experiment 1 in the article by Lee Brooks
demonstrates a double dissociation between
Articulatory Loop and Visuospatial Sketchpad
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:
Performance
Verbal Representation
(categorize words)
Spatial Representation
(categorize corners)
Verbal
Spatial
Response Modality
Working Memory “Modules”
• Interpretation:
– supports notion of modularity in Working
Memory (visuospatial sketchpad /
articulatory loop)
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
• 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
– This idea is formalized in so-called
“connectionist” networks
skiing
highschool
mockingbird
bird
canary
chicken
Mr. Lacey
To Kill A Mockingbird
racism
English
Martin Luther King
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