Perceptual load as a major determinant of the locus of selection in visual attention Lavie, N.,& Tsal, Y.(1994).  Percepti...
Overview <ul><li>Theoretical discussion  </li></ul><ul><ul><li>perceptual load </li></ul></ul><ul><li>Literature review  <...
Background <ul><li>Broadbent (1958): </li></ul><ul><ul><li>Early selection: </li></ul></ul><ul><ul><ul><li>Limited process...
Background <ul><li>Deutsch and Deutsch’s (1963): </li></ul><ul><ul><li>Late selection: </li></ul></ul><ul><ul><ul><li>Unli...
Background <ul><li>Kahneman and Treisman (1984): </li></ul><ul><ul><li>Paradigmatic shift </li></ul></ul><ul><ul><ul><li>F...
Some debate about early selection <ul><li>Broadbent’s filter model – limited capacity channel </li></ul><ul><li>Physical d...
<ul><li>Lavie:  </li></ul><ul><ul><li>Physical distinction->priority->cannot prevent irrelevant  info processing </li></ul...
The proposed model for selective attention <ul><li>Lavie’s premise: </li></ul><ul><ul><li>Limited capacity : </li></ul></u...
Literature review <ul><li>Structural approach </li></ul><ul><li>Perceptual load </li></ul><ul><li>Physical distinctiveness...
Literature review <ul><li>Qualitative </li></ul><ul><ul><li>Unlimited perception when one irrelevant stimulus is processed...
Perceptual load  Operational definition  <ul><li>No. of units/items  in the display </li></ul><ul><ul><li>Ex. A string of ...
Physical distinctiveness <ul><li>Major factor in determining nature of selection </li></ul><ul><li>Focus on location </li>...
Low perceptual load + poor physical distinction <ul><li>Poor distinction: </li></ul><ul><ul><li>relevant and irrelevant st...
Low perceptual load + poor physical distinction <ul><ul><li>Logan (1980): manipulate expectancy </li></ul></ul><ul><ul><li...
 
 
 
Low perceptual load + poor physical distinction <ul><ul><li>Eriksens and Schultz (1979): </li></ul></ul><ul><ul><ul><li>Pr...
Low perceptual load + poor physical distinction <ul><ul><li>Miller (1987): </li></ul></ul><ul><ul><li>Flank X target appea...
Low perceptual load + poor physical distinction
 
Low perceptual load + poor physical distinction <ul><ul><li>Lavie: </li></ul></ul><ul><ul><ul><li>Low load-> spare attenti...
Low perceptual load + poor physical distinction <ul><ul><li>Paquet and Lortie (1990): </li></ul></ul><ul><ul><ul><li>“ +” ...
Low perceptual load + clear physical distinction <ul><li>Eriksen (1974): </li></ul><ul><ul><li>Contour-to-contour distance...
<ul><li>Keren, O’Hara, and Skelton (1977): </li></ul><ul><ul><li>Same-different matching task </li></ul></ul><ul><ul><li>F...
 
 
<ul><li>Tipper (1985): </li></ul><ul><ul><li>Negative priming (NP) </li></ul></ul><ul><ul><li>Same identity, different sha...
 
<ul><li>Merikle and Gorewich (1979): </li></ul><ul><ul><li>Size, distance-> incompatible distractor-> interfere </li></ul>...
Manipulating display size   Studies with high perceptual load
Manipulating display size <ul><li>Clearer evidence that early selection is found  only  under conditions of high perceptua...
Items : letters + digits <ul><li>Low load display </li></ul><ul><ul><li>2 item  </li></ul></ul><ul><li>High load display <...
Results <ul><li>Color  =  no effect of display size nor of    distractor compatibility </li></ul><ul><li>Category  =displa...
2- item  4-item  <ul><li>responses when the distractor was incompatible than when it was neutral or compatible </li></ul><...
<ul><li>2. Kahneman and Chajczyk (1983) </li></ul><ul><li>“ manipulated perceptual load in a variation of the stroop task”...
 
Experiment .
 
Results <ul><li>Word spelt a compatible color naming responses were faster </li></ul><ul><li>Compatibility effect was redu...
Possible extensions to other modalities (auditory) <ul><li>Zelinker (1971) </li></ul><ul><li>Shadow  list of digits (4) </...
Results <ul><li>Easy shadowing  </li></ul><ul><li>Difficult shadowing </li></ul><ul><li>Resources  interference </li></ul>...
<ul><li>Barr and Kapadnis (1986) </li></ul><ul><li>” manipulating difficulty of the relevant task affects the ability to i...
Results <ul><li>Native speakers noticed more changes in unattended channel </li></ul><ul><li>Ex. Speech interruptions </li...
Summary <ul><li>Early or late selection is determined by:  </li></ul><ul><li>1) perceptual load  </li></ul><ul><li>2)physi...
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Perceptual Load

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Perceptual Load

  1. 1. Perceptual load as a major determinant of the locus of selection in visual attention Lavie, N.,& Tsal, Y.(1994). Perception & Psychophysics, Vol.56(2), 183-197.
  2. 2. Overview <ul><li>Theoretical discussion </li></ul><ul><ul><li>perceptual load </li></ul></ul><ul><li>Literature review </li></ul><ul><ul><li>Early and late selection </li></ul></ul><ul><li>Conclusion </li></ul>
  3. 3. Background <ul><li>Broadbent (1958): </li></ul><ul><ul><li>Early selection: </li></ul></ul><ul><ul><ul><li>Limited process </li></ul></ul></ul><ul><ul><ul><li>Analysis of physical features </li></ul></ul></ul>
  4. 4. Background <ul><li>Deutsch and Deutsch’s (1963): </li></ul><ul><ul><li>Late selection: </li></ul></ul><ul><ul><ul><li>Unlimited process </li></ul></ul></ul><ul><ul><ul><li>Parallel </li></ul></ul></ul><ul><ul><ul><li>Relevant response </li></ul></ul></ul>
  5. 5. Background <ul><li>Kahneman and Treisman (1984): </li></ul><ul><ul><li>Paradigmatic shift </li></ul></ul><ul><ul><ul><li>Filtering paradigm </li></ul></ul></ul><ul><ul><ul><ul><li>Shadowing task (Cherry,1953) </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Partial-report technique (Sperling,1960 ) </li></ul></ul></ul></ul><ul><ul><ul><li>Selective set paradigm </li></ul></ul></ul><ul><ul><ul><ul><li>Spatial and semantic priming </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Visual search experiment </li></ul></ul></ul></ul>
  6. 6. Some debate about early selection <ul><li>Broadbent’s filter model – limited capacity channel </li></ul><ul><li>Physical distinction rather than info load </li></ul><ul><li>Clear physical distinction of relevant info is insufficient for early selection </li></ul>
  7. 7. <ul><li>Lavie: </li></ul><ul><ul><li>Physical distinction->priority->cannot prevent irrelevant info processing </li></ul></ul><ul><ul><li>Perceptual load of relevant info </li></ul></ul><ul><ul><li>prevent irrelevant processing </li></ul></ul>
  8. 8. The proposed model for selective attention <ul><li>Lavie’s premise: </li></ul><ul><ul><li>Limited capacity : </li></ul></ul><ul><ul><ul><li>early selection </li></ul></ul></ul><ul><ul><ul><li>late selection (automatic process) </li></ul></ul></ul>
  9. 9. Literature review <ul><li>Structural approach </li></ul><ul><li>Perceptual load </li></ul><ul><li>Physical distinctiveness between relevant and irrelevant items </li></ul>
  10. 10. Literature review <ul><li>Qualitative </li></ul><ul><ul><li>Unlimited perception when one irrelevant stimulus is processed </li></ul></ul><ul><li>Quantitative </li></ul><ul><li>Limited perception but at the same time can accommodate more than one item </li></ul><ul><li>early selection =high perceptual load </li></ul><ul><li>Late selection = low perceptual load </li></ul>
  11. 11. Perceptual load Operational definition <ul><li>No. of units/items in the display </li></ul><ul><ul><li>Ex. A string of letters </li></ul></ul><ul><ul><li>word = 1 unit </li></ul></ul><ul><ul><li>letters = many units </li></ul></ul><ul><li>Nature of processing for each unit </li></ul>
  12. 12. Physical distinctiveness <ul><li>Major factor in determining nature of selection </li></ul><ul><li>Focus on location </li></ul><ul><li>Low load – poor distinction / clear distinction between target and distractor </li></ul>
  13. 13. Low perceptual load + poor physical distinction <ul><li>Poor distinction: </li></ul><ul><ul><li>relevant and irrelevant stimuli occupy the same location </li></ul></ul><ul><ul><li>Ex. Stroop task </li></ul></ul><ul><ul><li>Parallel processing of relevant and irrelevant dimensions </li></ul></ul><ul><ul><li>Asymmetric interference. ex.: word -> color </li></ul></ul>
  14. 14. Low perceptual load + poor physical distinction <ul><ul><li>Logan (1980): manipulate expectancy </li></ul></ul><ul><ul><li>Eriksens (1974): </li></ul></ul><ul><ul><ul><li>AUA AAUAA </li></ul></ul></ul><ul><ul><ul><li>irrelevant distractor is identified </li></ul></ul></ul>
  15. 18. Low perceptual load + poor physical distinction <ul><ul><li>Eriksens and Schultz (1979): </li></ul></ul><ul><ul><ul><li>Prolong the process of target-> increase distractor effect </li></ul></ul></ul>
  16. 19. Low perceptual load + poor physical distinction <ul><ul><li>Miller (1987): </li></ul></ul><ul><ul><li>Flank X target appear left </li></ul></ul><ul><ul><li>Flank O target appear right </li></ul></ul><ul><ul><ul><li>High correclation:88valid cue </li></ul></ul></ul><ul><ul><ul><li>8invalid cue </li></ul></ul></ul><ul><ul><ul><li>Low correclation:56valid cue </li></ul></ul></ul><ul><ul><ul><li>40invalid cue </li></ul></ul></ul>
  17. 20. Low perceptual load + poor physical distinction
  18. 22. Low perceptual load + poor physical distinction <ul><ul><li>Lavie: </li></ul></ul><ul><ul><ul><li>Low load-> spare attentional capacity-> irrelevant stimuli </li></ul></ul></ul>
  19. 23. Low perceptual load + poor physical distinction <ul><ul><li>Paquet and Lortie (1990): </li></ul></ul><ul><ul><ul><li>“ +” attenuates associated-flanker effect </li></ul></ul></ul><ul><ul><ul><li>Spatial precue reduced distractor effect but not eliminated it </li></ul></ul></ul>
  20. 24. Low perceptual load + clear physical distinction <ul><li>Eriksen (1974): </li></ul><ul><ul><li>Contour-to-contour distance </li></ul></ul>
  21. 25. <ul><li>Keren, O’Hara, and Skelton (1977): </li></ul><ul><ul><li>Same-different matching task </li></ul></ul><ul><ul><li>Flanking targets </li></ul></ul>
  22. 28. <ul><li>Tipper (1985): </li></ul><ul><ul><li>Negative priming (NP) </li></ul></ul><ul><ul><li>Same identity, different shape(letter) -> NP still occurred </li></ul></ul><ul><li>Tipper & Cranston (1985): </li></ul><ul><ul><li>Pictures and names -> NP still occurred </li></ul></ul><ul><li>Distractor was processed to the semantic level </li></ul><ul><li>low load-> clear distinction-> irrelevant processing </li></ul>
  23. 30. <ul><li>Merikle and Gorewich (1979): </li></ul><ul><ul><li>Size, distance-> incompatible distractor-> interfere </li></ul></ul><ul><li>Hagenaar and van der Heijden (1986): </li></ul><ul><ul><li>Color patch-> compatibility </li></ul></ul>
  24. 31. Manipulating display size Studies with high perceptual load
  25. 32. Manipulating display size <ul><li>Clearer evidence that early selection is found only under conditions of high perceptual load </li></ul><ul><li>Navon (1989) </li></ul><ul><li>“ possibility of early selection among all possible combinations of” </li></ul><ul><ul><li>physical properties {color , size} </li></ul></ul><ul><ul><li>Semantic property {relevant item: letter / digit} </li></ul></ul>
  26. 33. Items : letters + digits <ul><li>Low load display </li></ul><ul><ul><li>2 item </li></ul></ul><ul><li>High load display </li></ul><ul><ul><li>4 item </li></ul></ul><ul><ul><li>Distractor could be compatible / incompatible </li></ul></ul>1 Target ` 1 Distractor 1 Target ` 3 Distractors
  27. 34. Results <ul><li>Color = no effect of display size nor of distractor compatibility </li></ul><ul><li>Category =display size interacted with distractor compatibility effect </li></ul>
  28. 35. 2- item 4-item <ul><li>responses when the distractor was incompatible than when it was neutral or compatible </li></ul><ul><li>Late selection </li></ul><ul><li>No effect on distractor compatibility </li></ul><ul><li>Distractor interference was reduced when the load was relatively high </li></ul><ul><li>Thus early selection </li></ul>
  29. 36. <ul><li>2. Kahneman and Chajczyk (1983) </li></ul><ul><li>“ manipulated perceptual load in a variation of the stroop task” </li></ul><ul><li>RT for naming color of a central patch appearing together with a black word directly above or below it. </li></ul>
  30. 38. Experiment .
  31. 40. Results <ul><li>Word spelt a compatible color naming responses were faster </li></ul><ul><li>Compatibility effect was reduced when: 1. second neutral word </li></ul><ul><li>2. array of Xs was added </li></ul><ul><li>Reduction of attn. resources by neutral stimulus to capture incompatible distracting stimulus </li></ul><ul><li>“ Attn. resources are involuntarily allocated to irrelevant stimuli only when relevant processing is not sufficiently demanding.” </li></ul>
  32. 41. Possible extensions to other modalities (auditory) <ul><li>Zelinker (1971) </li></ul><ul><li>Shadow list of digits (4) </li></ul><ul><li>Ignore feedback of their voices (0.2s delay) </li></ul><ul><li>3 groups of shadowing </li></ul>
  33. 42. Results <ul><li>Easy shadowing </li></ul><ul><li>Difficult shadowing </li></ul><ul><li>Resources interference </li></ul>Delayed feedback difficult to ignore More stuttering Reduced interference
  34. 43. <ul><li>Barr and Kapadnis (1986) </li></ul><ul><li>” manipulating difficulty of the relevant task affects the ability to ignore an irrelevant auditory message ” </li></ul><ul><li>Standard shadowing test (English) </li></ul><ul><li>Native speakers and non native speakers </li></ul>
  35. 44. Results <ul><li>Native speakers noticed more changes in unattended channel </li></ul><ul><li>Ex. Speech interruptions </li></ul><ul><li>reduction in voice intensity </li></ul><ul><li>Changes caused more interferences in shadowing </li></ul><ul><li>Non-native speakers resources </li></ul><ul><li>processing of irrelevant message </li></ul>
  36. 45. Summary <ul><li>Early or late selection is determined by: </li></ul><ul><li>1) perceptual load </li></ul><ul><li>2)physical distinctiveness. </li></ul><ul><li>Early selection : </li></ul><ul><ul><li>desirable perceptual loads ↑ </li></ul></ul><ul><ul><li>possible when there is a clear distinction between relevant and irrelevant items </li></ul></ul>

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