Unit 2: Working Memory, Long Term Memory Flashcards
What is the definition of STM in the modal model?
single component short-term store
functions:
temporary storage - lists, task relevant info
transfer to LTM via rehearsal
a single system for holding and manipulating information for a wide variety of tasks such as learning, comprehension, and reasoning
What is a dual task?
- encode list of digits
- perform a cognitive task (e.g., reasoning, comprehension)
- recall list of digits
if both load and task make use of same store, then increasing load (to span) should disrupt performance on primary task
What are the concurrent tasks grammatical reason with memory load study by Baddeley 1986?
memory span task - provides a memory load
grammatical reasoning task
What is the procedure in the grammatical reason with memory load study by Baddeley 1986?
auditory presentation of digit load - 1 digit per second
concurrent overt rehearsal of load
visual presentation of letter pair & sentence
respond T/F to sentence
serial recall of digits
What is the design of the grammatical reason with memory load study by Baddeley 1986?
memory load: 0 to 8 digits
sentence type: true value X voice X affirmation
What are the implications of single-store view?
assumption:
span task - absorbs (almost) all STM capacity
reasoning task - requires access to STM
prediction:
if span task absorbs all of STM –> dual task requirements should produce a dramatic impairment in performance
span-length memory load –> catastrophic interference
What was the results of dual task reasoning?
no effect on reasoning when load is light (0-2)
reason showed by load
error rate low regardless of load
load also has negative, but non-catastrophic, impact on free recall & text comprehension
What is the implication of dual task performance?
system responsible for digit span cannot be the same as system responsible for learning/reasoning
motivated the development of the multi-component WM model
What is Baddeley and Hitch’s (1983) model of working memory?
central executive: control center of working memory
two subordinate systems:
phonological loop: processes verbal/acoustic information
visuo-spatial sketch pad: processes visual and spatial information
What is the working memory interpretation of dual task performance?
load maintenance requires: access to phonological store, minor attentional resources to schedule rehearsal
grammatical reasoning requires: attentional resources for sentence understanding/reasoning, limited access to phonological store
as load increases, attentional demands increase; thus, less capacity available for sentence processing
What are the two components of the phonological loop?
phonological short-term store: phonological information that decays with time, “inner ear”
subvocal rehearsal process: articulatory-like rehearsal that needs active maintenance, “inner voice”
What is the speech-based system in the phonological loop?
phonological similarity decrease
irrelevant speech decrease
articulatory suppression decrease
What is the 2 second capacity in the phonological loop?
word length effect
cross-linguistic changes
developmental changes
What is the phonological similarity effect?
similar sounding list < dissimilar sounding lists
(almost) no evidence for semantic similarity effect
What is the implication of the phonological similarity effect?
representation is speech-based not meaning based
What is the irrelevant speech effect?
recall impaired when items are accompanied by other verbal material
effect found with: same-language words, same-language non-words, foreign words
What is the interpretation of the irrelevant speech effect?
unattended (linguistic) material was gaining access to the phonological store
What is auditory suppression?
concurrent (overt or covert) articulation, decreases word span (“the, the, the…”; “one, two, three, one, two…)
concurrent articulation decreases: the phonological similarity effect, word length effect
What is the interpretation of auditory suppression?
articulation of irrelevant items dominates ACP - words cannot be “rehearsed” or recorded into phonological code
What is the word length effect?
word span decrease as number of syllables/word increases
recall depends of reading rate: number of words recalled ~2 (reading rate)
reading rate = number of words read per second
What is the study of the capacity of the phonological store by Baddeley et al. (1975)?
task: free recall
materials: 5-word lists
manipulation: syllable length
What are the results of the study of the capacity of the phonological store by Baddeley et al. (1975)?
recall decreased, as syllable length increased; recall predicted by reading rate
linear relation between reading time and recall
interpretation: capacity of phono loop is about 2 seconds of speech materials
reason: fast fading phono trace, rehearsal refreshes trace, if not rehearsed within 2 seconds, most info lost
What are the implications of the study of the capacity of the phonological store by Baddeley et al. (1975)?
across languages, digit span should be related to mean syllable length of digits
digit span should increase with age, because speech rate does
What are the cross-linguistic changes in digit span?
as predicted:
span larger for languages with short digits than long
span ~ 2 X reading rate
What are age related changes in digit span?
as predicted: span increases with age, span ~2 X speech rate
overt or covert articulation serves to maintain items in the phonological store by refreshing their fading traces
the faster it can run, the longer the memory span
How is the phonological loop implicated in learning to read?
children with impaired reading ability have reduced memory spans and have difficulties in tasks which require the manipulation of phonological information (e.g. given Stop, reply Top)
How is the phonological loop implicated in language comprehension?
STM patients some difficulty in comprehending verbose or complex sentences e.g.,
“The boys pick the apples” = OK
“The two boys pick the green apples from the tree” = impaired
How is the phonological loop implicated in vocabulary acquistion?
there is a strong correlation between non-word repetition (which strongly taxes the phonological loop) and vocabulary size
What is the visuo-spatial sketchpad?
function: construction, maintained, and manipulation of mental images
assumptions: independence of VSSP and phonological loop
operations: mental rotation, mental scanning, boundary extension, dynamic memory
supports: spatial problem solving (e.g., windows and couches), prediction of dynamic consequences
What is the mental rotation in the visuo-spatial sketchpad study by Shepard & Metzler (1971)?
materials: pairs of 3-D(ish) objects in a variety of orientations
task: timed same/different judgment
results: RT increases with angular disparity
interpretation: mental rotation has characteristics that mimic physical rotation.. it is almost as if people are actually mentally turning the object about in their VSSP
What is the episodic buffer?
multimodal information is bound together in the episodic buffer
this creates a (LTM) episodic memory trace
working memory interacts with long-term memory: intended to account for with semantic effects on STM task
How is the influence of LTM on STM task a problem with the model of working memory?
chunking
proactive interference and release from proactive interference
semantic similarity can increase span
span: high frequency words > low frequency words
What are the problems with the phonological loop?
under suppression: span > 0 for visually presented words
Why were alternative perspectives on working memory created?
problems with Baddeley’s Model
a need to better understand executive functioning
predictive power of span task
What are the three related issues with the alternative perspectives on working memory created?
reading/operation span as a measure of “capacity”
WM contents as the active portion of LTM
WM as executive attention
What is the process of measuring working memory capacity?
key idea: performance on complex cognitive task reflects a number of different capacities
retrieval efficiency, processing efficiency, “attention-free” capacity of relevant slave system, attentional management (ability to focus on relevant info & irrelevant info)
WM span tasks developed to measure relation between WM and performance on complex cognitive tasks
What is the WM memory span?
WM span = number of words recalled
demonstrates capacity for holding load while processing
large individual differences in WM span (2-6 items)
WM span measured predict performance on IQ, achievement tests (e.g., SATs), and g
digit/word span uncorrelated with IQ/SAT tests
What is Cowan’s embedded processes model?
central executive: directs and controls voluntary processing
encoding: incoming info activities representation in LTM
What is the central notion of Cowan’s embedded processes model?
LTM in one of 3 states:
1. Dormant
2. Activated: fades (decays) unless reactivated
3. “in focus” (of attention): limited to 4 items
What are the two components of the span from activation perspective?
read-out from focus
activated material, retrieved before decay
What are the predictions of the span from activation perspective?
factors increase LTM, increase span
concreteness: concrete > abstract
word frequency: high frequency > low frequency
span > 0 when rehearsal suppressed
What is domain specific capacity?
efficient processing of immediate task, leaves additional resources for maintaining load
accounts for dual-task
What is domain general capacity?
general ability to “control attention to maintain information in an active quickly retrievable state”
What is the main idea of span as executive control?
active, irrelevant info infers with performance
people differ in their ability to inhibited irrelevant info or remain focused on relevant info
What is the prediction of span as executive control?
individual differences in reading/operation span predict performance on tasks that require executive control
What is the span and proactive interference task?
participants: high-span or low-span
materials and procedure: 3 10-word lists (words from same category), 2 s/word, 16 s delay, 20 s recall periods
results: proactive interference worse for low-span
What is the span and anti-saccade task?
task: move eyes away from cue to find target
measures: distractibility
main finding: low span worse (more distractible) than high-span
What is the relationship between span and the Stroop task?
Stroop task - name color of font
general finding: incongruent trials slower than congruent trials
interpretation: response slowed because attention required to inhibit color name
What is the experiment on span and the Stroop task?
participants: low span vs high SP
congruence: 0%, 50%, 75%, difficulty increases with congruence
results: difficulty increases with congruence, low-span worse than high-span, effect increase with congruence
interpretation: inhibitory capacity particularly important when task is difficult
What was the conclusion regarding the alternatives to Baddeley’s view?
contents of WM: active portion of LTM
differences in capacity: reflects individual differences in ability to remain focused and inhibit irrelevant info
reflected in LTM and task perceptual tasks
What are the conclusions about working memory discussed in lecture?
no pure measure of STM: contents are focal info and activated LTM
covert rehearsal: one way of keeping info active
functional importance:
WM provides ability to access and maintain info in active state required for thought, language, problem solving, etc.; and to inhibit related/available, but potentially distracting info
