Post on 27-Apr-2018
2/14/2018
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Memory 2
Announcement
⢠Review Session
⢠Thursday, Feb 15th (tomorrow)
⢠5-6:30 pm
⢠Lattimore 201
⢠E-mail Carol (cjew@ur.rochester.edu) ahead of time if you havespecific questions/topics you would like them to cover
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Cannel Capacity of short-term memory?
⢠Demo--
⢠Just listenâŚ
⢠Donât write these down yet!
⢠When I stop, then write them down
Word Lists
⢠4 words: ⢠den
⢠cent
⢠fulfill
⢠reads
Word Lists
⢠6 words: ⢠fold
⢠blond
⢠depth
⢠colony
⢠volume
⢠stamp
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Word Lists
⢠8 words: ⢠portrait
⢠occur
⢠howdy
⢠cancel
⢠shops
⢠pony
⢠olive
⢠sadness
⢠hostile
⢠smoked
⢠leap
⢠noodles
⢠circuit
⢠salute
Word Lists
⢠12 words: ⢠sofa
⢠knives
⢠logic
⢠reunion
⢠messy
⢠pencil
⢠climate
⢠wax
⢠organs
⢠panel
⢠riot
⢠hunter
⢠bribe
⢠stressed
⢠shorts
⢠hatch
⢠chambers
⢠fragile
⢠sincere
⢠stunt
⢠junior
Word Lists
⢠15 words:
What strategies did you use?
⢠Rehearsal â repeating item to yourself over and over
⢠Chunking â re-coding the list into larger âchunksâ
⢠Adding a narrative â connecting the elements into an event
⢠Visualizing â using additional senses to strengthen the memory
⢠System of loci â imagining things in different spatial locations
⢠�
⢠Loss / Forgetting/ Attention â clearing your mind before each list
Chunking
⢠Try to remember the following string:
1 4 9 1 6 2 5 3 6 4 9 6 4 8 1 1 0 0 1 2 1
Chunking
⢠Get all that?
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Chunking
⢠How about if you divide it up into more meaningful chunks?
1, 4, 9, 1 6, 2 5, 3 6, 4 9, 6 4, 8 1, 1 0 0, 1 2 1
12, 22, 32, 42, âŚ, 112
⢠Potentially no limit to memory if chunked repeatedly
From Cowan reading
Both STM and WM rely on LTM
Otherwise, how would we know what to chunk?
7 Âą 2
⢠George Millerâs landmark 1956paper
⢠How much information canhuman memory carry?
⢠Uses Information Theory terminology:âbits of informationâ
â Think binary:3.25 bits = 23.25 = 9.5âŚ
7 Âą 2
⢠Bits of information for simple tasksroughly the same regardless of modality
7 Âą 2
⢠But! Words have more information in them than single lettersâŚ
⢠How does this affect number of items in memory span?
⢠It doesnât
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7 Âą 2 Chunks
⢠Can recode information into larger chunks
⢠Number of chunks is always around 7 ¹ 2
A closer lookâŚ
⢠Millerâs paper is foundational, but lacks complexity
â Are all items in the list equal?
â How does speed of information transfer affect memory?
â How does memory change with task demands?
Outline
⢠Types of Memory
â Sensory Memory
⢠Memory Capacity
⢠Memory Features
⢠Working Memory
(Much of the following material from the supplementary readings)
⢠Excellent book from expert memory researcher Alan Baddeley
⢠Over the years pushed & shaped our understanding of short-term / working memory
Alan Baddeley(1934 â present)
University of York
img: https://en.wikipedia.org/wiki/Alan_Baddeley
Serial Position effects
⢠Remember the 15 character password?
⢠Which characters were easiest to remember?
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Serial Position effects
⢠Primacy â the first items are privileged
⢠Recency â the most recent items are privileged
Primacy & Recency hold over longer lists, too
Explanation?
⢠Modal Explanation
â First items get rehearsed most
â Items moved to LTM when buffer is full
â Most recent items still stored in STM/WM
What happens if we�
⢠Slow down presentation, to allow more time for rehearsal?
Serial effects â slowed presentation
⢠No effect on recency
⢠Pre-recency items recalled better
What happens if we�
⢠Slow down presentation, to allow more time for rehearsal?
⢠WM decays over timeâŚ
â What if we delay recall?
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Serial effects - Delayed recall
⢠Recency effects are removed
What happens if we�
⢠Slow down presentation, to allow more time for rehearsal?
⢠WM decays over timeâŚ
â What if we delay recall?
⢠What about interfering with maintenance?
Serial effects - Intervening Tasks
⢠Demo--
⢠Try to remember thefollowing items
⢠Now count back from 201by 3
⢠Also blocks recency
⢠Wave⢠Arm⢠Ice⢠Cat⢠Middle⢠Egg⢠Blood⢠Window⢠Metal⢠Garden
Serial effects âPhonological Similarity Effect
⢠List 1
â Contain?
⢠Tan?
⢠Cap?
⢠List 2
â Contain?
⢠Day?
⢠Bug?
Serial effects âPhonological Similarity Effect
List 1: â˘Manâ˘Canâ˘Capâ˘Mapâ˘Panâ˘Tapâ˘Cat
List 2:â˘Pitâ˘Legâ˘Dayâ˘Topâ˘Cowâ˘Penâ˘Hot
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Serial effects âPhonological Similarity Effect
Phon. Sim.
Phon. Disim.
Semantically similar
Sem. Disim.
⢠Phonological Similarity leads to poor recall
⢠Semantic similarity only has a small effect
Immediate Recall Vs. LearningâŚ
⢠In this experiment (Baddeley, 1966)
â With longer lists (canât fit all into memory)
â If participants have to wait 20 minutes before recallâŚ
⢠Phonological Effects disappear
⢠Semantic Effects (synonyms) get larger
⢠Phon. Effect has to do with rehearsal
Outline
⢠Types of Memory
â Sensory Memory
⢠Memory Capacity
⢠Memory Features
⢠Working Memory
Chunking Capacity LimitsRevisited
⢠Some data from Broadbent
⢠Highly influential researcher in attention and short-term memory
⢠Watch for him again in Attention lectures!
Dates: https://en.wikipedia.org/wiki/Donald_Broadbent; img: http://www.mrc-cbu.cam.ac.uk/timeline/images/broadbent.jpg
Donald Broadbent(1926 â 1993)
Applied Psychology Research UnitUK Medical Research Council
Chunking Capacity LimitsRevisited
⢠Some data from Cowan
⢠A current big name in the âChunk capacityâ literature
⢠Specialty: Working memory
Dates: https://en.wikipedia.org/wiki/Nelson_Cowan; img: http://memory.psych.missouri.edu/cowan.shtml
Nelson Cowan(1951 â present)
University of Missouri
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7 Âą 2?
⢠Braodbent (1975)
⢠There are some pretty good reasons to doubt that ~7 is the short-term capacity
⢠Letâs re-examine Millerâs evidenceâŚ
7 Âą 2 chunks
⢠Bits of information for simple tasksroughly the same regardless of modality
~4
7 Âą 2?
⢠Letâs re-examine Millerâs evidenceâŚ
⢠And in the Recency effectsâŚ
â Recall: recency is tied to keeping things in your rehearsal loop
Immediate Recall
Delayed recall 7Âą2?
⢠Initial Items and middle items donât change much over time
⢠These must come from Long-term memory
⢠Last items are easily disrupted
⢠These items are lost from an active, working memory store
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Primacy & Recency holdover longer lists, too
~3-4
Q F X S
R U V M
L J D B
4!
7Âą2?
⢠Broadbent also mentions:
⢠Perfect Performance
⢠On average, people can recall about 7 digits from a list
⢠But how many can people almost always recall?
â About 3
7Âą2?
⢠Broadbent also mentions:
⢠Clustering
⢠If you monitor pauses in peoplesâ recall
⢠They pause longest between clumps of ~3 items
⢠Suggests we can only select ~3 items at a time, and then we chunk them
Cowan (2008) (reading)
⢠To get a true estimate of channel capacityâŚ
⢠Need to eliminate contamination from:
â Chunking, LTM
â Rehearsal (which can lead to chunking)
â (Unlimited) Sensory Memory
Cowan (2010)
⢠There is a central memory store limit of 3-5
⢠Longer verbal units (sentences / idioms)
â Limit = ~4
⢠If you block phonological loopby having participant say âthe, the, theâŚâ out loud
â Limit = ~3
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Cowan (2010)
⢠If you present people with simultaneousvisual and auditory information,
⢠and then pause and mask itâŚ
Cowan (2010)
⢠and then pause and mask itâŚ
⢠Recall:
â If asked to attend to squares⌠~4 items
â If asked to attend to sounds⌠~4 items
â If asked to attend to both⌠~4 items
Okay, soâŚ
⢠Comprehension question:
⢠A group of people hears a list of 15 wordsAt the end of the list they recall as many as possible
⢠How many are they likely to remember on average?
Human Performance
⢠Digit Span 7 +/-2
⢠Word Recall 7 +/-2
⢠Recency effects 3-4
⢠Running Memory 3-4
⢠Perfect Performance Digit Span 3-4
Theorized Underlying Structure
⢠Miller: Enough channel capacity for 7 +/-2 âchunksâ
⢠Broadbent: Memory buffer capacity⌠3-4 current items(aka â working memory)
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Moving away from a single store
⢠Is STM / WM one single thing?
⢠Sensory memory appears to have many different subtypesâŚMaybe working memory does, too?
Dual-task paradigm
⢠Ask participants to perform two tasks at once
⢠Measure their performance in each task
⢠See which tasks interfere with each other
â These tasks must be ones that draw from common resources
â Tasks that donât interfere must draw from separate resources
Task-specific Resources
⢠Brooksâ âblock letterâ task (1968):
â Participants were asked to imagine a block letter
â Then indicate whether each corner was on the top or bottom of the letter, moving counter-clockwise from the upper left
â Example:
Correct answer:yes, yes, yes, no, no, yes, yesyes, yes, no, no, yes
Yes
Yes
No
Brooks, L. R. (1968). Spatial and verbal components of the act of recall. Canadian Journal of Psychology/Revue canadienne de psychologie, 22(5), 349.
Task-specific Resources
⢠Brooksâ âblock letterâ task
⢠Try by answering verbally about Double-UâŚ
⢠Now try with pointingâŚ
Correct answer:yes, yes, yes, no, yes, yes, yes, yes, no, yes, yes, no, yes
Brooks, L. R. (1968). Spatial and verbal components of the act of recall. Canadian Journal of Psychology/Revue canadienne de psychologie, 22(5), 349.
Task-specific Resources
⢠Point (Y/N):Is it a top/ bottom corner?
Yes NoBrooks, L. R. (1968). Spatial and verbal components of the act of recall. Canadian Journal of Psychology/Revue canadienne de psychologie, 22(5), 349.
Task-specific Resources
⢠Brooksâ âblock letterâ spatial task:
⢠Easy if response is verbal(say âyesâ or ânoâ)
⢠Hard if response is spatial(point to âyesâ or ânoâ)
Brooks, L. R. (1968). Spatial and verbal components of the act of recall. Canadian Journal of Psychology/Revue canadienne de psychologie, 22(5), 349.
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Task-specific Resources
⢠Brooksâ sentence task:â You will hear a sentenceâ Indicate whether each word in the sentence is a noun
(either verbal or spatial as before)
⢠Hard if response is verbal ⢠Easy if response is spatial
An apple a day keeps the doctor away
no yes no yes no no yes no
Brooks, L. R. (1968). Spatial and verbal components of the act of recall. Canadian Journal of Psychology/Revue canadienne de psychologie, 22(5), 349.
Task Interference
⢠Two tasks will interfere if:
â They share sensory modality(e.g. both use visual input)
â They share same stages of mental processing(e.g. both depend on syntactic processing)
⢠Suggests Multiple Working Memory components
Brooks, L. R. (1968). Spatial and verbal components of the act of recall. Canadian Journal of Psychology/Revue canadienne de psychologie, 22(5), 349.
Task Interference
Block-Letter Task Sentence Task
Verbal Response (spoken)
Easy Hard
Spatial Response (pointing)
Hard Easy
Brooks, L. R. (1968). Spatial and verbal components of the act of recall. Canadian Journal of Psychology/Revue canadienne de psychologie, 22(5), 349.
Parts of the Working Memory System?
⢠Baddeley & Hitch (1974) â Working Memory
⢠Auditory
⢠Visual
⢠(Episodic Memory)
⢠Central Executive
â (Planning and setting goals)
Phonological Buffer / Phonological Loop
⢠Subvocalization
⢠Can repeat things in Echoic Memory âup to a few seconds
â Used in language
â Sounds may be more time-dependent than images, since sound inherently unfolds over time
Visuo-spatial Sketch Pad
⢠Evidence:
â Spatial problem-solving aided by visualâworking spaceâ
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Visuo-spatial Sketch Pad
â People with Williams Syndrome(Learning disability)
⢠Relatively preserved language and verbal STM
⢠Impaired spatial processing
â âshow a specific deficit in processing sentences involving spatial syntactic forms, such as above and below or inside and outsideâ(Baddeley, 2001, p.89)
Baddeley, A. (2001). âIs Working Memory Still Working?â American Psychologist, 56, 849â864.Phillips, C. E., Jarrold, C., Baddeley, A. D., Grant, J., & Karmiloff-Smith, A. (2004). Comprehension of spatial language terms in Williams syndrome: Evidence for an interaction between domains of strength and weakness. Cortex, 40(1), 85-101.
⢠Evidence:
â Spatial problem-solving aided by visual âworking spaceâ
â Visualizable words are easier to learn
⢠See also: Object-based Mnemonics
Visuo-spatial Sketch Pad
Baddeley, A. (2001). âIs Working Memory Still Working?â American Psychologist, 56, 849â864.Phillips, C. E., Jarrold, C., Baddeley, A. D., Grant, J., & Karmiloff-Smith, A. (2004). Comprehension of spatial language terms in Williams syndrome: Evidence for an interaction between domains of strength and weakness. Cortex, 40(1), 85-101.
Williams Syndrome
Typically Developing
Mild Learning Disability
Episodic Memory
⢠Combines elements into a single storyor âepisodeâ
⢠Evidence:â Span for unrelated words: ~5
Span for words in a sentence: ~16
â People with Severe memory damage can still process individual sentences (sentences longer than Phonological Buffer)And some show excellent recall on entire prose passages(with immediate recall)
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Central Executive
⢠Coordinates behavior of the buffers
⢠Keeps systems âon taskâ
⢠Turns off subsystems after task is over
⢠Evidence from people with frontal lobe damage
E.g. DorsoLateral Pre-Frontal Cortex (DLPFC) damagefrom Substance Abuse
Patient Data
⢠Patients with DLPFC damage have trouble with:
â Switching tasks
â Attention
â Inhibition
â Compulsive behavior
â Decision Making
â Risk Assessment
Gowin, J. L., Mackey, S., & Paulus, M. P. (2013). Altered risk-related processing in substance users: imbalance of pain and gain. Drug and alcohol dependence,132(1), 13-21.Aron, A. R., Robbins, T. W., & Poldrack, R. A. (2004). Inhibition and the right inferior frontal cortex. Trends in cognitive sciences,8(4), 170-177.
Example:
⢠Wisconsin Card Sorting Task tests ability to switch tasks
⢠Try a demo!(http://www.psytoolkit.org/experiment-library/wcst.html)
⢠For each new card (?)have to match to one of thepresented cards
⢠Have to guess at underlying matchingrule, which switches every few trials
Example:
⢠After guess, feedback: Yes / No(If yes, you know the current rule)(If no, try again with other rule)
⢠DLPFC damage:Trouble switching to new rules
⢠âPerseveration Errorsâ(After rule changes, keeps trying old rule)
All together:
⢠from Baddeley (2000âs)
⢠Hierarchy of components:
⢠N.b.: WM relies on LTM
Baddeley, A. (2003). Working memory: looking back and looking forward. Nature Reviews. Neuroscience, 4(10), 829.
Brain activation?
⢠Curtis & DâEsposito (2003)⢠Propose 4 major areas
for working memory:â (P) Parietal areas
⢠Stores information forlocation of objects
â (F) Frontal Eye-Fields⢠Visuospatial buffer
â (B) Brocaâs Area⢠Phonological buffer
â (D) Dorsolateral Prefrontal Cortex⢠Central Executive
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Concussion
⢠One thing people with concussions have is difficulty with memory
⢠We can use fMRI (brain scans) to see how their activity differs during WM tasks
Concussion
⢠Memory task and a visual/motor identical control
Keightley, M. L., Singh Saluja, R., Chen, J. K., Gagnon, I., Leonard, G., Petrides, M., & Ptito, A. (2014). A functional magnetic resonance imaging study of working memory in youth after sports-related concussion: is it still working?. Journal of neurotrauma, 31(5), 437-451.
Concussion
⢠âcompared to healthy children, concussed youths had significantly reduced task-related activity in bilateral dorsolateral prefrontal cortex, left premotor cortex, supplementary motor area, and left superior parietal lobule during performance of verbal and nonverbal working memory tasks.â (p. 437)
Military Research
⢠Restoring Active Memory (RAM) (lead: Dr. Justin Sanchez)https://www.darpa.mil/program/restoring-active-memory
â Traumatic Brain Injury in servicemembers
â 270,000 cases since 2000
â Long-term memory issues
â Few effective therapies currently exist
⢠Project Goals
â Identify circuits responsible for memory formation and recall
â Implantable Neuroprosthetics
â Help boost brain signals while encoding memories
â Make this tech available to civilians
https://www.darpa.mil/program/restoring-active-memory