Read: Loftus for Tuesday Vokey for April 14 Idea Journals due on the 16th

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” 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 F Y Y Y N

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 VerbalSpatial Y 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 Performance 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)