Memory 2 Announcement 📝€¦ · · 2018-02-16in attention and short-term memory •Watch for...

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 ([email protected]) ahead of time if you havespecific questions/topics you would like them to cover

📝

Cannel Capacity of short-term memory?

• Demo--

• Just listen…

• Don’t 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

mailto:[email protected]

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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 – repeating item to yourself over and over

• Chunking – re-coding the list into larger “chunks”

• Adding a narrative – connecting the elements into an event

• Visualizing – using additional senses to strengthen the memory

• System of loci – imagining things in different spatial locations

• …?

• Loss / Forgetting/ Attention – 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, …, 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 ± 2

• George Miller’s landmark 1956paper

• How much information canhuman memory carry?

• Uses Information Theory terminology:“bits of information”

– Think binary:3.25 bits = 23.25 = 9.5…

7 ± 2

• Bits of information for simple tasksroughly the same regardless of modality

7 ± 2

• But! Words have more information in them than single letters…

• How does this affect number of items in memory span?

• It doesn’t

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7 ± 2 Chunks

• Can recode information into larger chunks

• Number of chunks is always around 7 ± 2

A closer look…

• Miller’s paper is foundational, but lacks complexity

– Are all items in the list equal?

– How does speed of information transfer affect memory?

– How does memory change with task demands?

Outline

• Types of Memory

– 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 – 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 – the first items are privileged

• Recency – the most recent items are privileged

Primacy & Recency hold over longer lists, too

Explanation?

• Modal Explanation

– First items get rehearsed most

– Items moved to LTM when buffer is full

– Most recent items still stored in STM/WM

What happens if we…?

• Slow down presentation, to allow more time for rehearsal?

Serial effects – slowed presentation

• No effect on recency

• Pre-recency items recalled better



• WM decays over time…

– What if we delay recall?

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Serial effects - Delayed recall

• Recency effects are removed



• WM decays over time…

– 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 –Phonological Similarity Effect

• List 1

– Contain?

• Tan?

• Cap?

• List 2

– Contain?

• Day?

• Bug?


List 1: •Man•Can•Cap•Map•Pan•Tap•Cat

List 2:•Pit•Leg•Day•Top•Cow•Pen•Hot

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Phon. Sim.

Phon. Disim.

Semantically similar

Sem. Disim.

• Phonological Similarity leads to poor recall

• Semantic similarity only has a small effect

Immediate Recall Vs. Learning…

• In this experiment (Baddeley, 1966)

– With longer lists (can’t fit all into memory)

– If participants have to wait 20 minutes before recall…

• Phonological Effects disappear

• Semantic Effects (synonyms) get larger

• Phon. Effect has to do with rehearsal

Outline

• Types of Memory

– 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 – 1993)

Applied Psychology Research UnitUK Medical Research Council

Chunking Capacity LimitsRevisited

• Some data from Cowan

• A current big name in the “Chunk capacity” literature

• Specialty: Working memory

Dates: https://en.wikipedia.org/wiki/Nelson_Cowan; img: http://memory.psych.missouri.edu/cowan.shtml

Nelson Cowan(1951 – present)

University of Missouri

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7 ± 2?

• Braodbent (1975)

• There are some pretty good reasons to doubt that ~7 is the short-term capacity

• Let’s re-examine Miller’s evidence…

7 ± 2 chunks

• Bits of information for simple tasksroughly the same regardless of modality

~4

7 ± 2?

• Let’s re-examine Miller’s evidence…

• And in the Recency effects…

– Recall: recency is tied to keeping things in your rehearsal loop

Immediate Recall

Delayed recall 7±2?

• Initial Items and middle items don’t 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!

7±2?

• Broadbent also mentions:

• Perfect Performance

• On average, people can recall about 7 digits from a list

• But how many can people almost always recall?

– About 3

7±2?

• Broadbent also mentions:

• Clustering

• If you monitor pauses in peoples’ 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 capacity…

• Need to eliminate contamination from:

– Chunking, LTM

– Rehearsal (which can lead to chunking)

– (Unlimited) Sensory Memory

Cowan (2010)

• There is a central memory store limit of 3-5

• Longer verbal units (sentences / idioms)

– Limit = ~4

• If you block phonological loopby having participant say “the, the, the…” out loud

– Limit = ~3

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Cowan (2010)

• If you present people with simultaneousvisual and auditory information,

• and then pause and mask it…

Cowan (2010)

• and then pause and mask it…

• Recall:

– If asked to attend to squares… ~4 items

– If asked to attend to sounds… ~4 items

– If asked to attend to both… ~4 items

Okay, so…

• 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 “chunks”

• Broadbent: Memory buffer capacity… 3-4 current items(aka – 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 subtypes…Maybe 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

– These tasks must be ones that draw from common resources

– Tasks that don’t interfere must draw from separate resources

Task-specific Resources

• Brooks’ “block letter” task (1968):

– Participants were asked to imagine a block letter

– Then indicate whether each corner was on the top or bottom of the letter, moving counter-clockwise from the upper left

– 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.


• Brooks’ “block letter” task

• Try by answering verbally about Double-U…

• Now try with pointing…

Correct answer:yes, yes, yes, no, yes, yes, yes, yes, no, yes, yes, no, yes



• 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.


• Brooks’ “block letter” spatial task:

• Easy if response is verbal(say “yes” or “no”)

• Hard if response is spatial(point to “yes” or “no”)


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• Brooks’ sentence task:– You will hear a sentence– 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


Task Interference

• Two tasks will interfere if:

– They share sensory modality(e.g. both use visual input)

– They share same stages of mental processing(e.g. both depend on syntactic processing)

• Suggests Multiple Working Memory components


Task Interference

Block-Letter Task Sentence Task

Verbal Response (spoken)

Easy Hard

Spatial Response (pointing)

Hard Easy


Parts of the Working Memory System?

• Baddeley & Hitch (1974) – Working Memory

• Auditory

• Visual

• (Episodic Memory)

• Central Executive

– (Planning and setting goals)

Phonological Buffer / Phonological Loop

• Subvocalization

• Can repeat things in Echoic Memory –up to a few seconds

– Used in language

– Sounds may be more time-dependent than images, since sound inherently unfolds over time

Visuo-spatial Sketch Pad

• Evidence:

– Spatial problem-solving aided by visual“working space”

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– People with Williams Syndrome(Learning disability)

• Relatively preserved language and verbal STM

• Impaired spatial processing

– “show a specific deficit in processing sentences involving spatial syntactic forms, such as above and below or inside and outside”(Baddeley, 2001, p.89)

Baddeley, A. (2001). “Is Working Memory Still Working?” American Psychologist, 56, 849–864.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:

– Spatial problem-solving aided by visual “working space”

– Visualizable words are easier to learn

• See also: Object-based Mnemonics


Baddeley, A. (2001). “Is Working Memory Still Working?” American Psychologist, 56, 849–864.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 “episode”

• Evidence:– Span for unrelated words: ~5

Span for words in a sentence: ~16

– 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 “on task”

• 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:

– Switching tasks

– Attention

– Inhibition

– Compulsive behavior

– Decision Making

– 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

• “Perseveration Errors”(After rule changes, keeps trying old rule)

All together:

• from Baddeley (2000’s)

• 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 & D’Esposito (2003)• Propose 4 major areas

for working memory:– (P) Parietal areas

• Stores information forlocation of objects

– (F) Frontal Eye-Fields• Visuospatial buffer

– (B) Broca’s Area• Phonological buffer

– (D) Dorsolateral Prefrontal Cortex• Central Executive

http://www.psytoolkit.org/experiment-library/wcst.html

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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

• “compared 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.” (p. 437)

Military Research

• Restoring Active Memory (RAM) (lead: Dr. Justin Sanchez)https://www.darpa.mil/program/restoring-active-memory

– Traumatic Brain Injury in servicemembers

– 270,000 cases since 2000

– Long-term memory issues

– Few effective therapies currently exist

• Project Goals

– Identify circuits responsible for memory formation and recall

– Implantable Neuroprosthetics

– Help boost brain signals while encoding memories

– Make this tech available to civilians

https://www.darpa.mil/program/restoring-active-memory



Memory 2 Announcement 📝€¦ · · 2018-02-16in attention and short-term memory •Watch for...

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