P2 Lecture 6: Working Memory Flashcards
What is the evidence for visual codes used in STS (Kroll study)
Visual codes in STS
- Kroll had people do a shadowing task, and while they were shadowing they had to retain a test letter presented acoustically or visually
- shadowing requires a lot of AVL coding
- after some interval (between 1 -15 sec), they had to recall the letter
- At short intervals, people did very will with both auditory and visual
- At long interval, people did well only with visual (they were more likely to recall the letter if visually presented than auditory)
- The reason the auditory letter drops because they are doing a shadowing task which is verbal (AVL code), so you have two verbal tasks interfering with each other; suggests visual code of test letter can be maintained in STS, which is evidence for visual coding
What is the evidence for semantic code used in STS (Shulman)?
- presented a list of ten words (500ms each), and then given a probe word that either matched a word in the list or did not
- they were then asked whether the probe word was an item in the list or not
- the probe word was either semantically related or not (the probe word “ship” for “boat” is semantically related but shin is not)
- if we’re not coding things based on semantics in STS, then it shouldn’t matter if your probe word is ship or shin (it should be equally likely)
- however, people are more likely to have false positives when the probe word is semantically related to a word on the list (saying that the probe word ”ship” was on the list even though the list had “boat” instead)
What is working memory and the different components?
– active system for temporary store & manipulation of information
1) Central Executive
Plan actions, integrate information Initiate control/decision
Transfer of info to/from LTS
- rehearsal, recoding
2) Phonological Loop
3) Visuo-spatial Sketchpad
What are the general assumptions of working memory?
- There is only one WM System and it operates on many tasks (math, reading, driving)
- WM has a limited storage and processing capacity
- Demands of task #1 can limit performance on task #2
What are the assumptions regarding the subsystems of working memory?
1) Involve simple low-level processing
- rehearsal / maintenance of information
2) Subsystems are domain specific
- phonological vs. visuo-spatial
3) Each subsystem has own limited (small) pool of attentional resources
- may also drain (rely on) resources from the Central Executive (ex. chunking things)
What is the phonological loop of working memory?
– Speech & sound component; responsible for storage & rehearsal of verbal information, & phonological processing
– Two components
1) Phonological Store
» passive store that holds verbal information; forgotten unless rehearsed & refreshed
» memory poor when try to remember words that are similar
» “boat, bowl, bone , bore” harder than “stick, pear, friend, cake”
» why? Similar sound codes get confused in the phonological store
2) Articulatory Loop
active refreshing of verbal information
» memory for words poorer when concurrently trying to say something responsible for storage & rehearsal (saying “the” repeatedly while you are trying to remember a list of words)
» “act of speaking” uses up resources in the articulatory loop, so words from list cannot be refreshed and are lost
» Real world effect: it’s hard to read while in room with other people talking
– Musical pitch: find get confused by similar pitches just like the phonological similarity effect
– American Sign Language (ASL): Shand (1982)
» congenitally deaf, skilled at ASL
» presented word lists written or in ASL sign:
» word lists were either phonological similar (shoe, through, new) or cherologically similar (hand movements)
» found memory confusions based on cherological relatedness!
» deaf people coded (& recoded) in ASL, & used ASL code in phonological loop
What is the visuo-spatial sketchpad and the supporting evidence (mental rotation -Shepard & Metzler)?
– Maintenance and processing (manipulation) of visual and spatial information
– TWO PARTS; Visual Cache (storage) Inner Scribe (processing)
– Shepard & Metzler (1971)
» mental rotation of 3D objects
» people shown first figure
» indicate whether second figure is same or different
» requires mental rotation
» the higher the degree the rotation, the longer it takes to determine whether it’s the same shape or not
» conclude: visual codes can be are used to temporarily store and manipulate information in STS
What is the dual-task method?
- Focus is on evidence showing separate phonological loop vs. visuo-spatial sketchpad subsystems
- perform two tasks at same time (a phonological tasks time-shared with a visuo-spatial task)
- if tasks do not affect each other, assume utilizing different WM systems
- if task mutually interfere, assume tasks utilizing same WM system
What was the dual-task study by Logie, Zucco & Badd?
1) Primary Tasks: Visual-memory -- given a grid of squares on a display (half of the grid is randomly filled) and seen for 3s -- then a new display is presented with one of the squares moved to another location on the grid -- participants had to point out which one had moved -- requires visuo-spatial sketchpad Letter Memory Span -- remember 5 letters -- requires phonological loop 2) Secondary Tasks Mental Imagery Task -- hold mental image -- requires visuo-spatial sketchpad Simple Mental Addition Task -- 25 + 4 -- requires phonological loop
Results
- data represents drop in performance in the dual-task conditions versus original baseline performance
- graph shows interference was greatest for:
1) two phono tasks (Letter span + Adding)
2) two visual tasks (Visual span + Imaging)
- graph shows interference was greatest for:
Conclude: supports notion of separate phonological vs. visuo-spatial subsystems
What is the Neuropsychological evidence for separate WM systems?
– Phonological Loop
scans taken while rehearsing digits/letters
mostly left-hemisphere parietal & frontal lobe activation
Broca’s area 44, 40 (articulation)
Premotor and Supplementary Motor Area (6)
– Central Executive
task switching & dual-tasks
Brodmann’s area 46 (LH, DLPFC)
-- Visuo-Spatial Sketch Pad mainly right hemisphere areas including: occipital cortex posterior parietal lobe premotor and DLPFC regions object memory --> mainly DLPFC spatial location --> mainly premotor region
What is the PANT task (Dobbs & Rule)?
- Paced Auditory Naming Task (PANT)
- PANT task utilizes the Central Executive (have to keep track of where you are in that list)
- PANT; one person says a list of letters and another person repeats, but they have to either repeat the last two letters, last 3 letters, last 4 letters, or … (1, 6, 8, , 9, 5, 3, and you have to repeat every last 2 letters so 1, 8, 9,)
- this skill decreases in seniors (70+), but healthy seniors generally better than not independent seniors in nursing homes (less healthy)
What is the Johannsdottir & Herdman simulator driving study?
– Simulator driving study: - series of 60 sec trials
1) Primary task:
Drive and report relative locations of surrounding cars (front vs. back) at end of each trial.
2) Secondary tasks: verbal vs. spatial memory
Verbal : rhyming task
Spatial : tap a pattern on keypad
- locate cars in front + verbal rhyming = good
- locate cars in front + spatial tapping = poor
- locate cars behind + verbal rhyming = poor
- locate cars behind + spatial tapping = good performance
CONCLUDE
– Verbal WM (phonological loop) required for awareness of vehicles behind
– Spatial WM (visuo-spatial sketchpad) required for awareness of vehicles in front
(locating cars in front of you uses the visuo-spatial sketchpad because things in front of us are always changing and we have constant access to it so we recode it every single time it changes but things behind us, we use phonological coding because we check our mirrors occasionally)
What is the Heenan & Herdman (2014) driving study and conversation task?
– Simulator driving study with naturalistic conversation task
1) Primary task:
Drive and report relative locations of surrounding cars (front vs. back) at end of each trial.
2) Secondary task: 20-questions conversation task
- the driver asks a series of 20 questions to figure out experimenter’s target word (e.g., whale)
Results
– front of car in both conversation and no conversation both have high error rates (same)
– behind car in no conversation and conversation had less errors than front of car, however no conversation better than conversation in behind car
Conclude
– conversation utilizes WM and this lowers driver awareness of other cars
– conversation especially utilizes phonological WM (the phonological loop)
– the P-loop is required to keep track of vehicles behind them
Summary of WM
WM temporary hold and manipulation of info.
involves both storage and processing
WM has three components:
central executive, phonological loop, visuo- spatial sketchpad
WM involved in a range of everyday tasks.
reading, driving, math, way-finding, etc.
Individual differences in WM
may be specific changes to a WM component, such as with aging and Central Executive
