Higher Cognition 2 - Working Memory PBS5

  1. What type of experiments primarily determined what different components there were in the Working Memory model? Give an example study.
    • Dual-task experiments
    • eg. Robbins et al (1996)
    • Chess move selection and effect of several concurrent tasks
    • Key pressing task (visuo-spatial sketchpad) and random number generation (central executive) affected quality of chess moves.
    • However, word repetition task (involve phonological loop) had no effect.
    • Chess move selection involves central executive and visuospatial sketchpad, but not phonological loop.
  2. [Phonological loop] List the two key empirical findings that provide insights into the structure of the phonological loop.
    • Phonological similarity effect
    • Word length effect
  3. Describe the phonological similarity effect and the study associated with it.
    • Baddeley (1966)
    • Serial recall of list of phonologically similar words (eg. Fee, He, Knee) significantly worse than from list of phonologically dissimilar words (Bay, Hoe etc)
    • whereas semantic similarity had little effect on recall
    • Suggests that speech-based representations are used in storing the words (+ recall requires discrimination between memory traces)
  4. Describe the word length effect and study associated with it.
    • Recall of list of long words worse than recall of short words.
    • Cultural differences in mean digit span also illustrates this effect - Chinese digits are relatively quick to say, whereas in Welsh it is not. Digit span higher in China than in Wales (also could be correlated to maths performance?)
    • Baddeley (1975)
    • If word length effect due to phonological loop, disrupting subvocal rehearsal should reduce effect.
    • Participants silently mouth irrelevant digits (articulatory suppression) during presentation and recall of words
    • This eliminated word length effect - suggesting phonological storage capactiy determined by rate of rehearsal.
  5. So, from these 2 empirical findings, what did Baddeley conclude about the structure of the phonological loop?
    • Distinction between 2 components...
    • phonological store: speech perception
    • articulatory control process: speech production (giving access to phonological store for visual stimuli)
    • So... explanation for the findings
    • Phonoglocal similarity effect: confusion between similar representations in phonological store
    • Word length effect: time taken to rehearse longer words via articulatory control process
    • Image Upload 1
  6. [Visuospatial sketchpad] There have been less study on this one. Most have focused on what type of study? Give example.
    • The effect on different tasks of concurrent visual visuospatial processing
    • Baddeley et al (1975)
    • encode material either by rote verbal learning or imagery-based strategy
    • when task combines with pursuit rotor tracking (tracking a moving light) performance using imagery-based strategy was disrupted.
  7. However, Baddeley's use of rotor tracking involves both visual perception and spatial localisation. Which are more important for disrupting imgaery-based learning? Study please.
    • Baddeley & Lieberman (1980)
    • Repeated Baddeley (1975) experiment, but contrasting specifcally visual (making brightness judgments) and specifically spatial (pointing at moving pendulum while blindefolded, guided by auditory tone) concurrent tasks
    • Learning using imagery strategy disrupted most by spatial concurrent task
  8. From Badderley and Lieberman's study, it was shown that a distinction needed to be made between visual and spatial information processing. Who proposed this and what did it entail?
    • Logie (1995)
    • Visuospatial working memory can be divided into 2 components...
    • Visual cache: passively stores info about visual form and colour and decays and gets interfered by new info
    • Inner scribe: process spatial info and allows active rehearsal of info in visual cache
    • (However, lecturer thinks it is weak model - ASK!)
    • nU-JjyydJXDphhyxP89d4w_m
  9. How is Logie's model of visuospatial sketchpad supported by neuropsychological evidence?
    • Patient NL: preserved perceptual skills but could not describe details of scene from memory (Beschin et al)
    • Patient LH: perfrom better on spatial processing tasks than visual imagery (Farah et al)
  10. [Episodic buffer]. So, these teo systems allow temporary storage of modality-specific info, but various findings are difficult to explain with this distinct-systmes approach. Outline some of these findings.
    • Baddeley (1984): articulatory suppression does reduce memory span for visually-presented material too (from 7-->5) but doesn't eliminate it like phonological loop model predicts
    • Patients: with impaired ST phonological memory (with auditory span of 1 digit) can recall more digits with visual presentation (ASK WHY THIS IS RELEVANT!)
    • Chincotta et al (1999): dual-task method used to study memory span for Arabic numerals (1,2,3) and digit words (one, two, three). Participants used both verbal and visual representations in performing task.
    • These suggest verbal and visual info must be combined and stored somewhere in working memory.
  11. What was a further issue/phenomena that couldn't be explained simply by 2 modality-specific stores
    • Memory span for meaningful sentences can be as much as 15-16 words, much more than normal phonological loop capacity (Baddeley et al, 1987)
    • Traditional explanation is that info from LTM is used to integrate words into meaningful 'chunks'
    • BUT in densely amnesic patients (with grossly impaired LTM) can exhibit normal immediate sentence span (Baddeley & Wilson)
    • Also densely amnesic patient able to continue playing bridge, keeping track of all cards that have been played (Baddeley 2000)
    • Working memory model needed new temporary storage system allowing verbal and visual codes to be combined and linked into multi-modal representation.
  12. Outline the evidence from neuroimaging for a distinct, multi-modal short-term store.
    • Prabhakaran et al (2000)
    • Working memory task requiring retention of integrated verbal and spatial info
    • Result: activation in right frontal cortex greater for retention of integraded info - consistent with episodic buffer 
    • Posterior regions exhibited material-specific working memory effects - consistent with phonological loop and visuospatial sketchpad
    • Overall, episodic buffer useful addition, but lacks detailed account of how it integrates info from other components and from LTM is lacking.
  13. [Central executive] Most  important but least known about because of its complexity and somewhat vague specification. However, certain functions have been identified. What are they? (4)
    • Smith & Jonides (1999)
    • Identified major functions of central executive:
    • 1. switching attention between tasks
    • 2. planning sub-tasks to achieve a specified goal
    • 3. selective attention to certain stimuli while ignoring others
    • 4. updating and checking contents of other working memory stores
  14. Describe a study which demonstrated the existence/mechanism of central executive.
    • Baddeley (1996)
    • Random generation 
    • Participants hold 1-8 digits in mind while trying to generate random sequence of key presses. 
    • Randomness decreases as digit memory load increases 
    • Suggesting greater demands on general-purpose, limited capacity central executive
  15. What are other things Baddeley found about the central executive with the random generation paradigm?
    • Concurrently reciting alphabet or counting didn't affect performance but alternating between letters and numbers decreased randomness 
    • suggesting that rapid switching of attention is another function of central executive
  16. What is the impairment of the central executive called? What are the symptoms?
    • Dysexecutive syndrome
    • Rylander: disturbed attention, increased distractibility, difficulty grasping the whole of a complicated state of affairs, cannot master new types of task in new situations
  17. What brain regions are associated with dysexecutive syndrome?
    • D'Esposito: dorsolateral regions of frontal lobe show greater activity in dual-task than single-task conditions
    • Duncan et al: lateral frontal cortex is neural basis of 'general intelligence' characterised as specific system involve in control of diverse forms of behaviour.
  18. NOTE: Read summary slide on PP and ask lecturer questions! Bit hard to understand some of the bits - especially episodic buffer and central executive.
    Good job. Keep going Ron.
Card Set
Higher Cognition 2 - Working Memory PBS5
Lec2 - Working memory