Opportunities for extra credit:

Keep checking at:www.tatalab.ca

March 22

More about conscious perceptionOverview of Memory

March 24

Sensory Memory

March 29

Short-Term/Working Memory (Brooks expt. 1)

March 31

Long-Term Memory

April 5

NO CLASS

April 7

Long-Term Memory and False Memories (Loftus)

April 12Consciousness and “Perception without Awareness”

Subliminal Messages (Vokey and Read)

April 14

Memes (Dawkins)

Upcoming

“Types” of Memory

• Sensory Memory– brief ( < 1 second)– preattentive / parallel processing (very

large capacity)

Overview of Memory

• Atkinson-Shiffrin Model

Sensory Signals

Sensory Memory

Short-Term Memory

Long-Term Memory

ATTENTION

REHEARSAL

RETRIEVAL

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 ?!– 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”

• Verbal Task: indicate if each word is or is not a noun– “I went to the store to buy a loaf of bread.”– N N N N Y N N N Y N Y

Working Memory “Modules”

• Spatial Task: indicate if each corner points outside

FY Y

YN

Working Memory “Modules”

• In both tasks the information needed must be maintained (represented) in working memory

Working Memory “Modules”

• Response Modalities:

Say: “yes” “no” “no” Point to: Y or N

Verbal Spatial

Y NY NY NY NY N

Working Memory “Modules”

• Both response modalities also engage working memory

Working Memory “Modules”

• Prediction: – There should be interference when response modality

and task representation engage the same module– if there is only one kind of module, then there should

be interference between every pairing of representation to response

Working Memory “Modules”• result: a cross-over interaction (double dissociation

Perf

orm

ance

Response ModalityVerbal Spatial

Spatial Representation(categorize corners)

Verbal Representation(categorize words)

Working Memory “Modules”

• Interpretation:– supports notion of modularity in Working

Memory (visuospatial sketchpad / articulatory loop)