Lecture 5 Psyco 350, A1 Fall, 2006

1
Lecture 5 Psyco 350, A1Fall, 2006

• N. R. Brown

2
Outline

• Baddeleys Model of Working Memory
• Phonological Loop
• Visuo-spatial sketchpad
• Central Executive
• Problems w/ WM
• An Alternative Cowans Embedded Process Model

3
VSSP

• Function
• construction, maintained, manipulation of
  mental images. Radvansky, p. 97
• Assumptions
• Independence of VSSP Phonological Loop

4
Visuo-spatial sketchpad

• Operations
• Mental rotation
• Mental scanning
• Boundary extension
• Dynamic memory
• Supports
• Spatial problem-solving (moving a couch
• Prediction of dynamic consequences.

5
Independence of VSSP Phonological LoopBrooks
(1968)

• Dual Task Experiment
• Goal to demonstrate
• spatial response mode interference w/ spatial
  processing
• verbal response mode interferes w/ verbal
  processing
• cross-modal tasks produce little interference

6
Independence of VSSP Phonological LoopBrooks
(1968)

• Design (2X3)
• TASK X RESPONSE MODE
• image scanning pointing
• grammatical decision tapping
• 
  vocal

7
Brooks (1968) Image Scanning Task

• Given a block letter starting point
• If current corner is top or bottom ?yes
• Otherwise ?no

8
F
9
Brooks (1968) Image Scanning Task

• Answers to block F
• yes
• yes
• yes
• no
• no
• no
• no
• no
• no
• yes

10
Brooks (1968) Image Scanning Task

• Given a proverb/cliché
• If current word is noun ?yes
• Otherwise ?no
• Example
• A bird in the hand is not in the bush.

11
Brooks (1968) Grammatical Judgment Task

• Given a proverb/cliché
• If current word is noun ?yes
• Otherwise ?no
• Example
• A bird in the hand is not in the bush.
• n y n n y n n n n y

12
Brooks (1968) Response Modes

• While performing target task
• Vocal say yes/no
• Taping left tap yes right tap no
• Pointing point to successive y/n pairs on
  response sheet

13
Brooks (1968) Pointing
14
Brooks (1968) Results

gtgt
ltlt

• Spatial response mode
• interfered w/ spatial task
• did not interfere w/ verbal task
• Verbal response mode
• interfered w/ verbal task
• did not interfere w/ spatial task

15
Brooks (1968) Interperation

• Task X Mode interaction indicates
• separate limited pool of resources for verbal
  spatial task
• image scanning task spatial response mode draw
  on the limited resources of the VSSP.
• grammatical decision task vocal response mode
  both draw on the resources of the phonological
  loop.

16
Mental Rotation VSSP _at_ Work

• Shepard Metzler (1971)
• Materials Pairs of 3-d(ish) objects in a
  varierty of orientations.
• Task timed same/different judgment

17

• SAME 80? disparity in the picture plane

18

• SAME 80? disparity in depth

19

• DIFFERENT

20
Mental Rotation

• Results
• RT ? w/ 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.
• Radvansky, p. 99

21
Central Executive

• Most complex and least understood component of WM
• Coordinates activity of slave systems
  supplements their attentional resources
• Other potential roles
• coordinating retrieval strategies
• selective attention
• temporary activation of LTM,
• suppression of habitual responses.

22
Measuring WM 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 inhibit irrelevant info.
• etc.
• WM span tasks developed to measure relation
  between WM and performance on complex cognitive
  tasks

23
Daneman Carpenter (1980) Reading Span

• Read the sentences and recall the LAST word in
  each.

24

• When at last his eyes opened, there was no gleam
  of triumph, no shade of anger.

25

• The taxi turned up Michigan Avenue, where they
  had a they had a clear view of the lake.

26

• The senator who was attacked by the reporter was
  warned by the policeman.

27

• Recall the last word of each sentence.
• anger
• lake
• policeman

28
Turner Engle (1989) Operation Span

• Answer each math question and recall final word.

29

• Is (82)/2 5 HOUSE

30

• Is (9-3)X4 12? CHAIR

31

• (43)X2 14? DOG

32

• Recall words.
• HOUSE
• CHAIR
• DOG

33
WM Memory Span

• WM span of words recalled
• Demonstrates capacity for holding load while
  processing.
• Large individual differences in WM span (2-6
  items)
• WM span measures predict performance on IQ/
  achievement tests (e.g., SATs).
• digit/word span uncorrelated with IQ/SAT tests
• Interpretation Efficient processing of immediate
  task, leaves additional resources for maintaining
  load.

34
Problems w/ Baddeleys WM

• Influence of LTM on STM tasks
• chunking
• proactive interference (Keppel Underwood, 1962)
  release from proactive interference (Wickens,
  1972).
• semantic similarity can ? span
• span high frequency words gt low frequency words
• Problems with Phonological Loop
• negative word-length effects exist (Lovatt et al.
  2000)
• under suppression span gt 0 for visually
  presented words.

35
Current WM Model
36
Baddeleys Response The Episodic Buffer

• A limited capacity temporary storage system that
  is capable of integrating information from a
  variety of sources
• Controlled by Central Executive
• Feeds information into and retrieves information
  from LTS
• Uses a common multidimensional code
• The Episodic Buffer explicitly links WM and LTM

37
An Alternative WM as Activation
38
WM as Activation Cowans Embedded Processes
Model

• Central Executive directs and controls voluntary
  processing.
• Encoding
• Incoming info activities representation in LTM

39
WM as Activation Cowans Embedded Processes
Model

• Central Notation
• LTM in one of 3 states
• Dormant
• Activated
• fades (decays) unless reactivated
• In focus (of attention)
• limited to 4 items

40
Span from Active Persepsective

• Two components
• read-out from focus
• activated material, retrieved before decay
• Predictions
• factors ? LTM, ? span
• concreteness (Walker Hulme, 1999)
• word frequency (Roodenrys Quinlan, 2000)
• Span gt 0 when rehearsal suppressed

41
Conclusions

• No pure measure of STM
• Contents focal info activated LTM
• Covert Rehearsal
• one way of keeping info active
• Functional importance
• WM provides ability to access info and maintain
  in active state required for thought, language,
  problem-solving, etc