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

• Atkinson-Shiffrin Model

Sensory Signals

Sensory Memory

Short-Term Memory

Long-Term Memory

ATTENTION

REHEARSAL

RETRIEVAL

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” non-verbal information, such as a map

Are there two different STM systems?

A Modular Approach to STM

Articulatory Loop

Central Executive

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:

Per

form

ance

Response Modality

Verbal Spatial

Spatial Representation(categorize corners)

Verbal Representation(categorize words)

Working Memory “Modules”

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

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

• 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

birdcanary

chicken

mockingbird

To Kill A Mockingbird

racism

highschool

Martin Luther King

skiing

Mr. Lacey

English

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