Chapter 3

Divided attention
 Introduction
 Dual task experiments
 Theories
 Single or multiple processors?
 Summary
Introduction

 Doing two things at once
 Everyday experience
 Dual tasks
Dual task experiments

 Eysenck & Keane(1995) have identified
 three major factors that affect the
 ability to do two(or ...
Task similarity

 Allport et al.(1972):shadow prose and
  learn a list of words(recall)
 Present to the other ear(poor)
...
Task difficulty

 inter-individual
 intra-individual
 Combine with a second task
Practice

 Spelke et al.(1976):write down dictated
  words while reading short stories
 Reasons
1. Reduce the amount of ...
Theories
Central capacity theory

 Kahneman(1973)
 Attention as a skill rather than a process
 Mental effort=tasks require diffe...
Central capacity theory

Kahneman(1973)          Arousal
central processor
                        Available
             ...
Evaluation

 Task difficulty, the role of practice and
  arousal
 Problems
1. The limits of capacity
2. Does not explain...
Central capacity interference theory

 Norman and Bobrow(1975)
 Resource-limited & data-limited
Evaluation

 Cherry(1953)
 Failure to predict performance of tasks in
  experiments
 Non-falsifiable
Multiple channel theories
                         A limited capacity model


           A central processor              ...
Allport – modules of attention

 Attention consists of a number of specialised
  modules                                (...
(1)Listening to       (2)List of words
   a massage             to be learned


 (3)Shadowing
    message



(1)Listening ...
Evaluation of module theory

 To explain the effects of similarity in dual task
 experiments




                        ...
Evaluation of module theory

 The fundamental assumptions of cognitive
 neuropsychology
  Relatively   independent cogni...
Evaluation of module theory
 Problem 1                   Problem 2
   It doesn’t specify the      How the modules work...
Multiple Resource Theory

 Navon & Gopher (1979)
 - specialized “mental resources” (like modules)
 - performance can be t...
Multiple Resource Theory




Input              Processing             Response
                   Information

    • Stim...
Multiple Resource Theory


               Saws           Lathes

                       Dri
                        ll



...
Multiple Resource Theory

 Dawson and Schell (1982)
- Shadowed a message
- Classically conditioned word in non-attended e...
Multiple Resource Theory

 Payne and Wenger (1998)
- Single capacity model
                = response in both ears or nei...
Multiple Resource Theory

 Failure to specify number of resources
 How the multiple resources work together
 Attentiona...
Single or Multiple Processors?

 Flaws with both models
  Single capacity models fail to account for effect of
   simila...
Single or Multiple Processors?

 Baddeley (1986)
- Synthesis theory
 -   combine features of both approaches
       - cen...
Single or Multiple Processors?

                             Central Executive
                             (central, limi...
Single or Multiple Processors?

 Good compromise?
 Still got problems
 Role of the central executive
 How different co...
Summary

 Divided attention
 - studied using dual task experiments
 - influenced by task similarity
                 task...
Summary

 Kahneman
    - single, limited capacity central processor
    - explains effect of task difficulty and practice...
Summary

 Norman and Bobrow
    - modified version of central capacity model
    - tasks: resource-limited
             d...
Summary

 Allport
    - modular approach
    - different modules with individual resources &
     capacities
    - better...
Summary

 Navon and Gopher
    - multiple resource theory
    - similar to Allport
    - similar strength and weakness
Summary

 Baddeley
    - synthesis theory
    - central limited capacity processor
    - individual processors for differ...
THANKS FOR
YOUR LISTENING
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Chapter3

  1. 1. Chapter 3 Divided attention
  2. 2.  Introduction  Dual task experiments  Theories  Single or multiple processors?  Summary
  3. 3. Introduction  Doing two things at once  Everyday experience  Dual tasks
  4. 4. Dual task experiments  Eysenck & Keane(1995) have identified three major factors that affect the ability to do two(or more) tasks at once  Task similarity  Task difficulty  Practice
  5. 5. Task similarity  Allport et al.(1972):shadow prose and learn a list of words(recall)  Present to the other ear(poor)  Print on a screen  Present as pictures on a screen(very good)  It is a difficult concept to define
  6. 6. Task difficulty  inter-individual  intra-individual  Combine with a second task
  7. 7. Practice  Spelke et al.(1976):write down dictated words while reading short stories  Reasons 1. Reduce the amount of resource 2. Help participants learn strategies
  8. 8. Theories
  9. 9. Central capacity theory  Kahneman(1973)  Attention as a skill rather than a process  Mental effort=tasks require different processing capacity  The difficulty of the task & the degree of practice
  10. 10. Central capacity theory Kahneman(1973) Arousal central processor Available Capacity Enduring Dispositions Allocation Policy Momentary Intentions Evaluation Possible Responses of Demands on Capacity Response
  11. 11. Evaluation  Task difficulty, the role of practice and arousal  Problems 1. The limits of capacity 2. Does not explain the strong influence of similarity
  12. 12. Central capacity interference theory  Norman and Bobrow(1975)  Resource-limited & data-limited
  13. 13. Evaluation  Cherry(1953)  Failure to predict performance of tasks in experiments  Non-falsifiable
  14. 14. Multiple channel theories A limited capacity model A central processor A single filter Explaining the complex Dealing with all nature of attention (Neisser, attentional tasks? 1976 ; Allport, 1993) ? Dealing with many different types of task required by an attentional system ? •It is difficult to see how the neurology of the brain could produce a system of processing a capacity (Hampson and Morris,1996)
  15. 15. Allport – modules of attention  Attention consists of a number of specialised modules (Allport, 1980,1983)  Each module deal with a different ability or skill  Each module has its own resources and a limited capacity  Wicken, 1984  Different modules may deal with different aspects of a task  Modules exist for input/processing/output mode
  16. 16. (1)Listening to (2)List of words a massage to be learned (3)Shadowing message (1)Listening to a massage (1)List of pictures (3)Shadowing to be learned message
  17. 17. Evaluation of module theory  To explain the effects of similarity in dual task experiments (Allport et al.,1972 Treisman and Davies, 1973)
  18. 18. Evaluation of module theory  The fundamental assumptions of cognitive neuropsychology  Relatively independent cognitive processors or modules  Each one can function to some extent in isolateion  Brain damage (Eysenck and Keane, 1995)  Only some of these modules are impaired
  19. 19. Evaluation of module theory  Problem 1  Problem 2  It doesn’t specify the  How the modules work number of modules together?  What types of modules  How the modules are they are? co-ordinated  The theory is therefore  Enough practice non-falsifiable  The similar tasks can work concurrently  Competing for the resources of one module (Underwood, 1974; Spelke et al., 1976)
  20. 20. Multiple Resource Theory  Navon & Gopher (1979) - specialized “mental resources” (like modules) - performance can be traded (new concept) - supply and demand  Good explanation of effect of task similarity in dual task experiments (Allport et al, 1972)
  21. 21. Multiple Resource Theory Input Processing Response Information • Stimuli • Transformation • Output
  22. 22. Multiple Resource Theory Saws Lathes Dri ll Drill Finished Raw Material Product
  23. 23. Multiple Resource Theory  Dawson and Schell (1982) - Shadowed a message - Classically conditioned word in non-attended ear (left or right) - Conditioning = paired with mild electric shock - Subsequent recognition = autonomic nervous system response - Left vs. right hemisphere - Left for speech reception and production - Right for speech analysis - Automated response to unattended message in left ear but not right ear
  24. 24. Multiple Resource Theory  Payne and Wenger (1998) - Single capacity model = response in both ears or neither - Multiple resource model = response to each ear differently - Not able to detect unattended message in right ear - Left hemisphere is for speech reception and production, and primary task (shadow message) takes priority - Not enough resources to analyze unattended message at the same time
  25. 25. Multiple Resource Theory  Failure to specify number of resources  How the multiple resources work together  Attentional processes highly integrated HOW?
  26. 26. Single or Multiple Processors?  Flaws with both models  Single capacity models fail to account for effect of similarity in dual task experiment  Multiple capacity models fail to explain how different parts of attention work together
  27. 27. Single or Multiple Processors?  Baddeley (1986) - Synthesis theory - combine features of both approaches - central, limited capacity processor (from central capacity theory) - modality-specific processing systems (from modular or multiple resource theory)
  28. 28. Single or Multiple Processors? Central Executive (central, limited capacity processor) Modality-specific processing systems Visuo- Spatial Phonological Loop Sketchpad
  29. 29. Single or Multiple Processors?  Good compromise?  Still got problems  Role of the central executive  How different components are integrated
  30. 30. Summary  Divided attention - studied using dual task experiments - influenced by task similarity task difficulty task practice
  31. 31. Summary  Kahneman - single, limited capacity central processor - explains effect of task difficulty and practice - does not explain effect of task similarity on performance
  32. 32. Summary  Norman and Bobrow - modified version of central capacity model - tasks: resource-limited data-limited - more flexible model - problem: non-falsifiable
  33. 33. Summary  Allport - modular approach - different modules with individual resources & capacities - better at explaining influence of task similarity - supported by findings of cognitive neuropsych - problem: does not specify number of modules how modules are integrated
  34. 34. Summary  Navon and Gopher - multiple resource theory - similar to Allport - similar strength and weakness
  35. 35. Summary  Baddeley - synthesis theory - central limited capacity processor - individual processors for different tasks
  36. 36. THANKS FOR YOUR LISTENING
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