VISUALATTENTION: Control, Representation, and Time Course Howard E. Egeth and Steven Yantis Department of Psychology, The ...
1. Attentional control Top-down control  (goal-directed) Bottom-up control  (stimulus-driven) 2. Representational basis fo...
<ul><li>Deployment of attention </li></ul><ul><li>sometimes -> </li></ul><ul><li>exclusively depends on the properties of ...
<ul><li>Deployment of attention </li></ul><ul><li>Distribution of attention can be controlled by the intentions of the obs...
<ul><li>Feature Singletons </li></ul><ul><li>1. Stimuli that differ substantially in one or more simple visual attribute(e...
<ul><li>Feature Singletons </li></ul><ul><li>1. Stimuli that differ substantially in one or more simple visual attribute(e...
<ul><li>Singletons Capture Attention </li></ul>Reaction time OO / OO   //// O  <   O O / O O   / // / O < Reaction time < ...
<ul><li>Singletons capture attention </li></ul>STIMULUS-DRIVEN & GOAL-DIRECTED CONTROL OF ATTENTION cue array target array...
<ul><li>Singletons Do Not Capture Attention </li></ul>H R S O X Z E I V P B J A G W Q L U Y M K T N C F G R E O Z B T H C ...
<ul><li>Singletons Do Not Capture Attention </li></ul>Hillstrom & Yantis (1994) Feature Singletons & Attentional Capture T...
<ul><li>Attentional Control …… a possible reconciliation </li></ul><ul><li>Singleton Detection Mode </li></ul><ul><li>The ...
<ul><li>Peripheral cue draws attention automatically, </li></ul><ul><li>whereas a central arrowhead cue requires a deliber...
STIMULUS-DRIVEN & GOAL-DIRECTED CONTROL OF ATTENTION <ul><li>Peripheral cues might  capture attention because they have ab...
 
STIMULUS-DRIVEN & GOAL-DIRECTED CONTROL OF ATTENTION Yantis & Jonides (1984) Abrupt Visual Onsets & Attentional Capture Th...
STIMULUS-DRIVEN & GOAL-DIRECTED CONTROL OF ATTENTION <ul><li>Two potential mechanisms could account for attentional captur...
 
 
 
 
EXP3
STIMULUS-DRIVEN & GOAL-DIRECTED CONTROL OF ATTENTION <ul><li>Yantis & Hillstrom used stimuli that were equiluminant with t...
STIMULUS-DRIVEN & GOAL-DIRECTED CONTROL OF ATTENTION <ul><li>Irrelevant feature singletons capture attention only when sub...
STIMULUS-DRIVEN & GOAL-DIRECTED CONTROL OF ATTENTION <ul><li>Any given perceptual act entail an attentional control settin...
EXP1 TABLE
EXP2 TABLE
 
STIMULUS-DRIVEN & GOAL-DIRECTED CONTROL OF ATTENTION <ul><li>The deployment of attention depends critically on what the su...
STIMULUS-DRIVEN & GOAL-DIRECTED CONTROL OF ATTENTION <ul><li>Wolfe’s Guided search model </li></ul><ul><li>Attention is di...
STIMULUS-DRIVEN & GOAL-DIRECTED CONTROL OF ATTENTION <ul><li>The deployment of attention depends jointly on properties of ...
exp1
exp2
THE REPRESENTATIONAL BASIS OF VISUAL SELECTION “ If attention selects a stimulus, what is the stimulus that it selects?”
Viewpoint 1 <ul><li>Hoffman & Nelson (1981): identify a target and then identify a secondary shape </li></ul><ul><li>Downi...
Viewpoint 2 <ul><li>Kahneman & Henik (1981):  attention might be directed not only to spatial locations but also to percep...
Overlap and Grouping <ul><li>Rock & Guttman (1981): </li></ul><ul><li>1.The judgment task of the object drawn  </li></ul><...
Overlap and Grouping <ul><li>Duncan (1984):  a display consisting of a rectangle with a tilted line drawn through the midd...
Overlap and Grouping <ul><li>when attention is directed to one part of an object, other parts of the object enjoy an atten...
Overlap and Grouping <ul><li>Eriksen & Eriksen (1974):the noise letters were assigned to a response that conflicted with t...
Motion <ul><li>Kahneman et al (1992) </li></ul><ul><li>An object file: a temporary episodic representation of a visual obj...
Motion <ul><li>The target follows the onset of the cue by 150 ms or less(speed) ; or more than 300 ms(slow),  inhibition o...
Motion <ul><li>Gibson & Egeth(1994) argued that the conception of an object as  independent  of location should not be und...
The Time Course Of Attention
<ul><li>- Directing Attention </li></ul><ul><li>how quickly attention can be directed at a particular stimulus </li></ul><...
Directing  Attention <ul><li>Muller & Rabbitt (1989) </li></ul>
Directing  Attention Peripheral cue: fast, transient response Central cue: slow, sustained response  = deliberate shift of...
Dwell Time of Attention (Visual Search) <ul><li>Estimate amount of time spent per item in the visual display </li></ul><ul...
Dwell Time of Attention (Visual Search)
Dwell Time of Attention (RSVP-whole) <ul><li>Sequential display of stimuli </li></ul><ul><li>Saarinen & Julesz (1991) </li...
Dwell Time of Attention (RSVP-whole)
Dwell Time of Attention (RSVP-whole) <ul><li>Different approach: how slowly stimuli needed to be presented to keep report ...
Dwell Time of Attention (RSVP-whole) <ul><li>Haber & Nathanson (1969) </li></ul><ul><ul><li>Words that varied from 4 to 8 ...
Dwell Time of Attention (RSVP-partial) <ul><li>Problems w/ whole report </li></ul><ul><li>Use of words: guessing strategie...
Dwell Time of Attention (RSVP-partial) <ul><li>Broadbent & Broadbent (1987) </li></ul>
Dwell Time of Attention (RSVP-partial) <ul><li>consistent w/ Duncan (1980) </li></ul>
Rapid serial visual presentation   partial report <ul><li>Weichselgartner and Sperling(1987) </li></ul><ul><ul><li>Memory ...
Rapid serial visual presentation   partial report <ul><li>Raymond et al.(1992) </li></ul><ul><ul><li>A suppression of visu...
<ul><li>RSVP with a multi-item sequence </li></ul><ul><ul><li>A daunting task  </li></ul></ul><ul><li>Duncan et al.(1994) ...
Why the discrepant results -1  <ul><li>Moore et al(1996) </li></ul><ul><ul><li>Dwell time </li></ul></ul><ul><ul><ul><li>D...
Why the discrepant results -1  <ul><li>Moore et al(1996) </li></ul><ul><ul><li>Masking status  affecting the dwell time <...
Why the discrepant results -2 <ul><li>Bennett and Wolfe(1996) </li></ul><ul><ul><li>Visual search  RSVP </li></ul></ul><u...
The movement of attention <ul><li>Attention shifting from one location to another in the visual field </li></ul><ul><ul><l...
An analog and continuous fashion -1 <ul><li>Shul-et al ( 1979  ) </li></ul><ul><ul><li>Like a spotlight  </li></ul></ul><u...
An analog and continuous fashion -2 <ul><li>Eriksen & Murphy (1987) and Yantis (1988) </li></ul><ul><ul><li>Not including ...
An abrupt relocation- 1 <ul><li>Sagi and Julesz (1985) </li></ul><ul><ul><li>Discrimination accuracy was independent of di...
An abrupt relocation- 2 <ul><li>Sagi & Julesz (1985) and Kwak et al.(1991) </li></ul><ul><ul><li>Tasks was accomplished pr...
An abrupt relocation- 3 <ul><li>A serial processing </li></ul><ul><ul><li>Additive </li></ul></ul><ul><li>A parallel proce...
An abrupt relocation- 4 <ul><li>Sperling and Weichselgartner(1995) </li></ul><ul><ul><li>↑ distance -> ↑time to move  </li...
 
Hoffman & Nelson (1981) L L Conclusion: identification accuracy was much better when the two stimuli were adjacent to each...
Downing & Pinker (1985) Cued Box Luminance increment (target event) Conclusion: RT was fastest when the target event occur...
The Gestalt Laws <ul><li>Nearness </li></ul><ul><li>Similarity </li></ul><ul><li>Good continuation </li></ul>
Rock & Guttman (1981) Cover task Conclusion:   attended items are more than unattended or new items; unattended and new it...
Duncan (1984) Conclusion: more accurate when the attributes belonged to the same object .
Egly et al (1994) Conclusion: RTs in the same-object condition were faster than in the different-object condition.
Kahneman et al (1992) S P 500ms 1s ? 590ms Conclusion: naming latencies were much slower for no-match trials than for the ...
Tipper et al (1991) 180° target Conclusion: RT was slower when the target appeared within the previously cued object, whic...
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Attention Presentation

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Attention Presentation

  1. 1. VISUALATTENTION: Control, Representation, and Time Course Howard E. Egeth and Steven Yantis Department of Psychology, The Johns Hopkins University, Baltimore, Maryland 21218
  2. 2. 1. Attentional control Top-down control (goal-directed) Bottom-up control (stimulus-driven) 2. Representational basis for visual selection. 3. Time course of attention.
  3. 3. <ul><li>Deployment of attention </li></ul><ul><li>sometimes -> </li></ul><ul><li>exclusively depends on the properties of the image. </li></ul><ul><li>other times -> </li></ul><ul><li>under strict supervision according to the observer’s goals. </li></ul><ul><li>in a few exceptions -> </li></ul><ul><li>both 2 determine the attentional consequences. </li></ul><ul><li>These 2 domains of attentional control invariably interact. </li></ul>STIMULUS-DRIVEN & GOAL-DIRECTED CONTROL OF ATTENTION
  4. 4. <ul><li>Deployment of attention </li></ul><ul><li>Distribution of attention can be controlled by the intentions of the observer. </li></ul><ul><li>Two major categories of stimulus properties that could in principle capture attention can be distinguished : </li></ul><ul><li>Feature Singletons </li></ul><ul><li>& </li></ul><ul><li>Abrupt Visual Onsets </li></ul>STIMULUS-DRIVEN & GOAL-DIRECTED CONTROL OF ATTENTION
  5. 5. <ul><li>Feature Singletons </li></ul><ul><li>1. Stimuli that differ substantially in one or more simple visual attribute(e.g. color, orientation, motion) from their backgrounds. </li></ul><ul><li>2. Feature singletons are judged as subjectively salient. </li></ul><ul><li>3. Such stimuli can be found efficiently in visual search. </li></ul><ul><li>If feature singletons capture attention? </li></ul><ul><li>In cited cases, the stimulus in question was itself the target of search, and therefore presumably elicited top-down control. </li></ul><ul><li>One have to explicitly dissociate the observer’s attentional set from the properties of the stimulus array. </li></ul>STIMULUS-DRIVEN & GOAL-DIRECTED CONTROL OF ATTENTION Feature Singletons & Attentional Capture
  6. 6. <ul><li>Feature Singletons </li></ul><ul><li>1. Stimuli that differ substantially in one or more simple visual attribute(e.g. color, orientation, motion) from their backgrounds. </li></ul><ul><li>2. Feature singletons are judged as subjectively salient. </li></ul><ul><li>3. Such stimuli can be found efficiently in visual search. </li></ul>STIMULUS-DRIVEN & GOAL-DIRECTED CONTROL OF ATTENTION Feature Singletons & Attentional Capture
  7. 7. <ul><li>Singletons Capture Attention </li></ul>Reaction time OO / OO //// O < O O / O O / // / O < Reaction time < Theeuwes (1992) Pashler (1988) Feature Singletons & Attentional Capture STIMULUS-DRIVEN & GOAL-DIRECTED CONTROL OF ATTENTION
  8. 8. <ul><li>Singletons capture attention </li></ul>STIMULUS-DRIVEN & GOAL-DIRECTED CONTROL OF ATTENTION cue array target array L T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T Joseph & Optican (1996) Feature Singletons & Attentional Capture Attention was drawn to the cue even though it was known to be irrelevant to the task.
  9. 9. <ul><li>Singletons Do Not Capture Attention </li></ul>H R S O X Z E I V P B J A G W Q L U Y M K T N C F G R E O Z B T H C I S D Y J P Q L U N M K A W F V P R O C T Z Q N V Y E K A J F X L I W G B H U M P M C Y J R O G T W C V A Y E K N P X M Z U Q F B H I P L K Jonides & Yantis (1988) Feature Singletons & Attentional Capture Reaction time to find the target did not differ whether the target was the unique element or not. STIMULUS-DRIVEN & GOAL-DIRECTED CONTROL OF ATTENTION
  10. 10. <ul><li>Singletons Do Not Capture Attention </li></ul>Hillstrom & Yantis (1994) Feature Singletons & Attentional Capture T T T T T T T T T T T T T T T T L T T T T T T T T Moving element Target element T T T T T T T T T T T T T T T T L T T T T T T T T Target element and also the Moving element STIMULUS-DRIVEN & GOAL-DIRECTED CONTROL OF ATTENTION Reaction time of the moving targets did not differ from the stationary ones.
  11. 11. <ul><li>Attentional Control …… a possible reconciliation </li></ul><ul><li>Singleton Detection Mode </li></ul><ul><li>The location of the largest or the greater contrast can be accessed, but not the identity of the dimension(s) on which the stimuli differ. </li></ul><ul><li>When searching for a shape singleton, an irrelevant color singleton may win out. </li></ul><ul><li>Feature Search Mode </li></ul><ul><li>Attention is directed to locations that match some task-defined visual feature (e.g. “red” or “vertical”). </li></ul>Feature Singletons & Attentional Capture Bacon & Egeth (1994) STIMULUS-DRIVEN & GOAL-DIRECTED CONTROL OF ATTENTION
  12. 12. <ul><li>Peripheral cue draws attention automatically, </li></ul><ul><li>whereas a central arrowhead cue requires a deliberate shift of attention. </li></ul><ul><li>Peripheral cues drew attention whether they were informative about the location of the target or not, while central cues only controlled the deployment of attention when they were informative. </li></ul>Abrupt Visual Onsets & Attentional Capture Jonides (1981) STIMULUS-DRIVEN & GOAL-DIRECTED CONTROL OF ATTENTION
  13. 13. STIMULUS-DRIVEN & GOAL-DIRECTED CONTROL OF ATTENTION <ul><li>Peripheral cues might capture attention because they have abrupt onset. </li></ul>Yantis & Jonides (1984) Abrupt Visual Onsets & Attentional Capture A visual search task searching for a prespecified target letter embedded in an array of nontarget letters.
  14. 15. STIMULUS-DRIVEN & GOAL-DIRECTED CONTROL OF ATTENTION Yantis & Jonides (1984) Abrupt Visual Onsets & Attentional Capture The target happened to be the onset letter The target was one of the no-onset letters < Reaction time
  15. 16. STIMULUS-DRIVEN & GOAL-DIRECTED CONTROL OF ATTENTION <ul><li>Two potential mechanisms could account for attentional capture by abrupt onset. </li></ul><ul><li>1. Luminance increment activates Visual pathways, and it also direct attention to the eliciting object. </li></ul><ul><li>2. The appearance of a perceptual object. This might be a hard-wired response to the need to rapidly identify new objects entering the visual field. </li></ul>Abrupt Visual Onsets & Attentional Capture Yantis & Hillstrom (1994)
  16. 21. EXP3
  17. 22. STIMULUS-DRIVEN & GOAL-DIRECTED CONTROL OF ATTENTION <ul><li>Yantis & Hillstrom used stimuli that were equiluminant with their background. These displays thus exhibited no change in mean luminance, but they did include the appearance of a new perceptual object. </li></ul><ul><li>Attention was captured by new perceptual objects even though they didn’t exhibit a luminance increment. </li></ul>Abrupt Visual Onsets & Attentional Capture Yantis & Hillstrom (1994)
  18. 23. STIMULUS-DRIVEN & GOAL-DIRECTED CONTROL OF ATTENTION <ul><li>Irrelevant feature singletons capture attention only when subjects enter singleton detection mode. </li></ul><ul><li>Attentional capture by abrupt onset can be modulated by focused attention elsewhere in the display. </li></ul>Interaction of Goal-Driven & Stimulus-Driven Capture
  19. 24. STIMULUS-DRIVEN & GOAL-DIRECTED CONTROL OF ATTENTION <ul><li>Any given perceptual act entail an attentional control setting. </li></ul><ul><li>The attentional control setting is part of the explicit or implicit set of perceptual goals held by the observer at the specific moment. </li></ul><ul><li>The visual features that are of current interest(e.g. “red” or “vertical”) will control the distribution of attention. </li></ul>Interaction of Goal-Driven & Stimulus-Driven Capture Folk.Remington.Johnston(1992)
  20. 25. EXP1 TABLE
  21. 26. EXP2 TABLE
  22. 28. STIMULUS-DRIVEN & GOAL-DIRECTED CONTROL OF ATTENTION <ul><li>The deployment of attention depends critically on what the subject is set for. </li></ul><ul><li>When the cue and target were of the same type, i.e. both color or both onset, cue validity had a large effect. </li></ul><ul><li>Whereas the cue and target were of different types, then the cue had little or no influence on response time. </li></ul><ul><li>The state of attentional readiness adopted by the observer determines what sort of feature singletons will capture attention. </li></ul>Interaction of Goal-Driven & Stimulus-Driven Capture Folk.Remington.Johnston(1992)
  23. 29. STIMULUS-DRIVEN & GOAL-DIRECTED CONTROL OF ATTENTION <ul><li>Wolfe’s Guided search model </li></ul><ul><li>Attention is directed to objects serially in order of priority. </li></ul><ul><li>Top-down activation </li></ul><ul><li>How closely an object matches the current attentional set. </li></ul><ul><li>Bottom-up activation </li></ul><ul><li>How much a given object differs from neighboring objects within any given perceptual dimension. </li></ul><ul><li>Attention map </li></ul><ul><li>Determines the order in which objects are visited during visual search. </li></ul>Interaction of Goal-Driven & Stimulus-Driven Capture Wolfe (1994)
  24. 30. STIMULUS-DRIVEN & GOAL-DIRECTED CONTROL OF ATTENTION <ul><li>The deployment of attention depends jointly on properties of the image and the goals and expectation of the observer. </li></ul>Interaction of Goal-Driven & Stimulus-Driven Capture William James
  25. 31. exp1
  26. 32. exp2
  27. 33. THE REPRESENTATIONAL BASIS OF VISUAL SELECTION “ If attention selects a stimulus, what is the stimulus that it selects?”
  28. 34. Viewpoint 1 <ul><li>Hoffman & Nelson (1981): identify a target and then identify a secondary shape </li></ul><ul><li>Downing & Pinker (1985): cued box & target event </li></ul>
  29. 35. Viewpoint 2 <ul><li>Kahneman & Henik (1981): attention might be directed not only to spatial locations but also to perceptual objects. </li></ul><ul><li>the Gestalt psychologists </li></ul>
  30. 36. Overlap and Grouping <ul><li>Rock & Guttman (1981): </li></ul><ul><li>1.The judgment task of the object drawn </li></ul><ul><li>2. A surprise recognition test </li></ul>
  31. 37. Overlap and Grouping <ul><li>Duncan (1984): a display consisting of a rectangle with a tilted line drawn through the middle. </li></ul>
  32. 38. Overlap and Grouping <ul><li>when attention is directed to one part of an object, other parts of the object enjoy an attentional benefit, whereas equally distant locations in other objects do not. </li></ul><ul><li>Egly et al (1994) </li></ul>
  33. 39. Overlap and Grouping <ul><li>Eriksen & Eriksen (1974):the noise letters were assigned to a response that conflicted with the response associated with the target letter, responses were significantly slowed </li></ul><ul><li>Baylis & Driver (1992) </li></ul><ul><li>X H S H X H X S X H </li></ul>
  34. 40. Motion <ul><li>Kahneman et al (1992) </li></ul><ul><li>An object file: a temporary episodic representation of a visual object, containing a record of its location, its various attributes, and its recent history </li></ul>
  35. 41. Motion <ul><li>The target follows the onset of the cue by 150 ms or less(speed) ; or more than 300 ms(slow), inhibition of return (IOR) paradigm(Posner et al,1985) </li></ul><ul><li>Tipper et al (1991) </li></ul>
  36. 42. Motion <ul><li>Gibson & Egeth(1994) argued that the conception of an object as independent of location should not be understood to imply that an object is devoid of location. </li></ul><ul><li>Although objects are distinct from the spatial locations that they occupy, there exist other intraobject locations that may be fixed with respect to the overall object </li></ul>
  37. 43. The Time Course Of Attention
  38. 44. <ul><li>- Directing Attention </li></ul><ul><li>how quickly attention can be directed at a particular stimulus </li></ul><ul><li>Dwell Time of Attention </li></ul><ul><li>how long attention remains at a particular stimulus </li></ul><ul><li>Visual Search </li></ul><ul><li>Rapid Serial Visual Presentation (RSVP) </li></ul><ul><li>- whole report, partial report, minimal sequence </li></ul><ul><li>Movement of Attention </li></ul><ul><li>how attention moves from location to location </li></ul>Time Course of Attention
  39. 45. Directing Attention <ul><li>Muller & Rabbitt (1989) </li></ul>
  40. 46. Directing Attention Peripheral cue: fast, transient response Central cue: slow, sustained response = deliberate shift of attention
  41. 47. Dwell Time of Attention (Visual Search) <ul><li>Estimate amount of time spent per item in the visual display </li></ul><ul><li>Wolfe et al (1989) </li></ul>
  42. 48. Dwell Time of Attention (Visual Search)
  43. 49. Dwell Time of Attention (RSVP-whole) <ul><li>Sequential display of stimuli </li></ul><ul><li>Saarinen & Julesz (1991) </li></ul>SOAs: 33, 67, or 100 ms
  44. 50. Dwell Time of Attention (RSVP-whole)
  45. 51. Dwell Time of Attention (RSVP-whole) <ul><li>Different approach: how slowly stimuli needed to be presented to keep report accuracy at a high level </li></ul><ul><li>Kolers & Katzman (1966) </li></ul><ul><ul><li>6 letters sequentially, same spatial location </li></ul></ul><ul><ul><li>SOA of 375 ms for over 90% accuracy </li></ul></ul>
  46. 52. Dwell Time of Attention (RSVP-whole) <ul><li>Haber & Nathanson (1969) </li></ul><ul><ul><li>Words that varied from 4 to 8 letters </li></ul></ul><ul><ul><li>Critical SOA for 4 letter word= 65 ms, for 8 letter word = 110 ms </li></ul></ul><ul><li> </li></ul><ul><li>problems </li></ul>
  47. 53. Dwell Time of Attention (RSVP-partial) <ul><li>Problems w/ whole report </li></ul><ul><li>Use of words: guessing strategies </li></ul><ul><li>Random letter strings: memory requirement > task performance </li></ul><ul><li>RSVP- partial report: report 1 or 2 “target items” in the stream </li></ul><ul><li>Broadbent & Broadbent (1987) </li></ul>
  48. 54. Dwell Time of Attention (RSVP-partial) <ul><li>Broadbent & Broadbent (1987) </li></ul>
  49. 55. Dwell Time of Attention (RSVP-partial) <ul><li>consistent w/ Duncan (1980) </li></ul>
  50. 56. Rapid serial visual presentation partial report <ul><li>Weichselgartner and Sperling(1987) </li></ul><ul><ul><li>Memory mechanisms </li></ul></ul><ul><ul><li>Attentional processes </li></ul></ul><ul><ul><li>Perceptual processes </li></ul></ul>
  51. 57. Rapid serial visual presentation partial report <ul><li>Raymond et al.(1992) </li></ul><ul><ul><li>A suppression of visual processing </li></ul></ul><ul><ul><ul><li>Perceptual and attentional mechanisms blink </li></ul></ul></ul><ul><ul><li>A dual-task RSVP experiment </li></ul></ul><ul><ul><ul><li>The consequences associated with paying attention to a target </li></ul></ul></ul><ul><ul><ul><li>Posttarget performance deficits </li></ul></ul></ul><ul><ul><ul><ul><li>Sensory factors </li></ul></ul></ul></ul><ul><ul><ul><li>% correct detections of the probe </li></ul></ul></ul><ul><ul><ul><ul><li>As a function of the probe position of in the series </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Attentional blink </li></ul></ul></ul></ul>
  52. 58. <ul><li>RSVP with a multi-item sequence </li></ul><ul><ul><li>A daunting task </li></ul></ul><ul><li>Duncan et al.(1994) </li></ul><ul><ul><li>Stimuli were close together in time </li></ul></ul><ul><ul><ul><li>The first stimulus interfered with the second </li></ul></ul></ul><ul><ul><li>Dwell time of attention </li></ul></ul><ul><ul><ul><li>An index of the time course of the first object’s attentional demand </li></ul></ul></ul><ul><ul><ul><li>500ms </li></ul></ul></ul>Rapid serial visual presentation minimal sequences-1
  53. 59. Why the discrepant results -1 <ul><li>Moore et al(1996) </li></ul><ul><ul><li>Dwell time </li></ul></ul><ul><ul><ul><li>Depending on specific stimuli and tasks? </li></ul></ul></ul><ul><ul><li>Duncan et al(1994) and Ward et al(1995) </li></ul></ul><ul><ul><ul><li>Masked stimuli </li></ul></ul></ul><ul><ul><ul><li>A difficult discrimination > an easy discrimination </li></ul></ul></ul>
  54. 60. Why the discrepant results -1 <ul><li>Moore et al(1996) </li></ul><ul><ul><li>Masking status  affecting the dwell time </li></ul></ul><ul><ul><li>Dwell time in easy method </li></ul></ul><ul><ul><ul><li>↓ 200ms </li></ul></ul></ul>
  55. 61. Why the discrepant results -2 <ul><li>Bennett and Wolfe(1996) </li></ul><ul><ul><li>Visual search  RSVP </li></ul></ul><ul><ul><li>Fell only at 26 ms </li></ul></ul>
  56. 62. The movement of attention <ul><li>Attention shifting from one location to another in the visual field </li></ul><ul><ul><li>An analog and continuous fashion </li></ul></ul><ul><ul><li>An abrupt relocation </li></ul></ul>
  57. 63. An analog and continuous fashion -1 <ul><li>Shul-et al ( 1979 ) </li></ul><ul><ul><li>Like a spotlight </li></ul></ul><ul><li>Tsal ( 1983 ) </li></ul><ul><ul><li>Attention takes time to move </li></ul></ul><ul><ul><ul><li>↑ distance -> ↑time to move </li></ul></ul></ul><ul><ul><li>Cue should be beneficial </li></ul></ul><ul><ul><ul><li>Maximum benefit of the cue </li></ul></ul></ul><ul><ul><ul><ul><li>Further away from fixation </li></ul></ul></ul></ul>
  58. 64. An analog and continuous fashion -2 <ul><li>Eriksen & Murphy (1987) and Yantis (1988) </li></ul><ul><ul><li>Not including a control for general arousal or alertness </li></ul></ul><ul><ul><li>Attention shifting </li></ul></ul><ul><ul><ul><li>Continuous or discrete dynamics? </li></ul></ul></ul>
  59. 65. An abrupt relocation- 1 <ul><li>Sagi and Julesz (1985) </li></ul><ul><ul><li>Discrimination accuracy was independent of distance </li></ul></ul><ul><li>Kwak et al.(1991) </li></ul><ul><li>Remington and Piere(1984) </li></ul>
  60. 66. An abrupt relocation- 2 <ul><li>Sagi & Julesz (1985) and Kwak et al.(1991) </li></ul><ul><ul><li>Tasks was accomplished preattentively </li></ul></ul><ul><ul><ul><li>Being little reason to speak of reallocation of attention </li></ul></ul></ul>
  61. 67. An abrupt relocation- 3 <ul><li>A serial processing </li></ul><ul><ul><li>Additive </li></ul></ul><ul><li>A parallel processing </li></ul><ul><ul><li>Subadditive </li></ul></ul>
  62. 68. An abrupt relocation- 4 <ul><li>Sperling and Weichselgartner(1995) </li></ul><ul><ul><li>↑ distance -> ↑time to move </li></ul></ul><ul><ul><li>Attention can skip over an intervening obstacle without any time cost </li></ul></ul><ul><ul><li>Quantum </li></ul></ul>×
  63. 70. Hoffman & Nelson (1981) L L Conclusion: identification accuracy was much better when the two stimuli were adjacent to each other
  64. 71. Downing & Pinker (1985) Cued Box Luminance increment (target event) Conclusion: RT was fastest when the target event occurred within the cued box
  65. 72. The Gestalt Laws <ul><li>Nearness </li></ul><ul><li>Similarity </li></ul><ul><li>Good continuation </li></ul>
  66. 73. Rock & Guttman (1981) Cover task Conclusion: attended items are more than unattended or new items; unattended and new items did not differ .
  67. 74. Duncan (1984) Conclusion: more accurate when the attributes belonged to the same object .
  68. 75. Egly et al (1994) Conclusion: RTs in the same-object condition were faster than in the different-object condition.
  69. 76. Kahneman et al (1992) S P 500ms 1s ? 590ms Conclusion: naming latencies were much slower for no-match trials than for the other conditions; RTs were significantly faster for the same object condition than for the different object condition . S V S
  70. 77. Tipper et al (1991) 180° target Conclusion: RT was slower when the target appeared within the previously cued object, which suggested that IOR is object-based under these conditions . Cued box Cued box

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