Chapter 8. Shifting Spatial Attention
8.1 Title slide
Demonstration 8.3
true
true
You must read each slide, and complete any questions on the slide, in sequence.
true
title
Shifting Spatial Attention
Participate in an experiment aimed at assessing how long it takes to shift your attention.
CLICK ANYWHERE TO BEGIN
Road signs direct our attention to upcoming changes in the road or a potential danger. Our visual system makes use of these sorts of attentional cues to speed up our responses to those conditions.
[Photo: © Jetta Productions, Inc./Spaces Images/Corbis.]
[Photo: © Jetta Productions, Inc./Spaces Images/Corbis.]
How Does the Locus of Attention Affect the Time Needed to Detect Visual Stimuli?
Attentional cuing—providing a cue about the location of an upcoming target stimulus—can be used to examine how the spatial location of a person's attention (the locus of attention) affects the speed with which the person can become aware of the target and respond to it.
In a typical experiment (Posner et al., 1978), the participant was instructed to fixate on a point at the center of a visual display (Time 1 in Figure 1a). One of three cues then appeared in the display for one second (Time 2): a left- or right-pointing arrow indicated that the participant should direct her attention to the corresponding side of the fixation point, because she'd been told that a target was likely to appear in that location; a plus sign was a neutral cue, indicating that the target was equally likely to appear in either location. Regardless of where she directed her attention, the participant was required to keep her gaze on the fixation point. The target then appeared (Time 3), and the participant had to press a button as soon as she saw it.
When the cue indicated that the participant should direct her attention to the left or the right, the target appeared on that side in 80% of the trials (these were called valid cues) and on the other side in 20% of the trials (invalid cues); when the cue was neutral, the target appeared equally often on either side.
Figure 1b shows that the time required to press the button—the response time—was significantly faster when the target followed a valid cue than when it followed an invalid cue, with the response time to targets following neutral cues somewhere in between. This indicates that detecting the target is significantly faster when it appears in an attended location than when it appears in an unattended location. It's as if an "attentional spotlight" is directed to the cued location, and this speeds perception.
In a typical experiment (Posner et al., 1978), the participant was instructed to fixate on a point at the center of a visual display (Time 1 in Figure 1a). One of three cues then appeared in the display for one second (Time 2): a left- or right-pointing arrow indicated that the participant should direct her attention to the corresponding side of the fixation point, because she'd been told that a target was likely to appear in that location; a plus sign was a neutral cue, indicating that the target was equally likely to appear in either location. Regardless of where she directed her attention, the participant was required to keep her gaze on the fixation point. The target then appeared (Time 3), and the participant had to press a button as soon as she saw it.
When the cue indicated that the participant should direct her attention to the left or the right, the target appeared on that side in 80% of the trials (these were called valid cues) and on the other side in 20% of the trials (invalid cues); when the cue was neutral, the target appeared equally often on either side.
Figure 1b shows that the time required to press the button—the response time—was significantly faster when the target followed a valid cue than when it followed an invalid cue, with the response time to targets following neutral cues somewhere in between. This indicates that detecting the target is significantly faster when it appears in an attended location than when it appears in an unattended location. It's as if an "attentional spotlight" is directed to the cued location, and this speeds perception.
8.2 Activity
activity_8_3_slide_2
8.3 Activity
activity_8_3_slide_3
Before each trial, you’ll see this fixation circle at the center of the display for 1 second,
before the cue appears. Remember to keep your eyes fixed on this location.
PRESS THE SPACEBAR TO INITIATE THE SIX PRACTICE TRIALS
8.4 Activity
activity_8_3_slide_4
Now it’s time to begin the actual experiment—120 trials like the practice trials.
It should take you 5–10 minutes to complete all 120 trials.
Be sure to complete all the trials—if you don’t, you won’t be able to see your results.
The computer will be measuring your response time in each trial, so be sure to press the spacebar as soon as you see the square target.
Throughout the experiment, you must keep your eyes fixed on the center of the display (the location occupied by the black circle below).
PRESS SPACEBAR TO BEGIN
8.5 Activity
You must select an answer and then click SUBMIT before you can click proceed to the next screen
activity_8_3_slide_5
PRESS THE SPACEBAR TO START
Trial 1 of 120
8.6 Activity
You must select an answer and then click SUBMIT before you can click proceed to the next screen
activity_8_3_slide_6
The graphs below show the response times on trials where the cue (an arrow or a plus sign) was valid, invalid, or neutral:
• 80% of the arrow cues were valid (the arrow pointed to the side where the target appeared).
• 20% of the arrow cues were invalid (the arrow pointed away from the side where the target appeared).
• The plus sign cues were neutral (the target appeared to the left of the cue 50% of the time and to the right 50% of the time).
The graph on the left is based on the results from the original 1978 experiment and reflects the typical group results from this type of experiment. The graph on the right shows your median response time for each type of cue (valid, invalid, or neutral). In both graphs, a lower response time means a faster response.
Typical group results
Typically, participants respond fastest after valid cues, slower after neutral cues, and slowest after invalid cues.
Your results
How do your results compare to the typical group results? There are many reasons why your results might differ, including the relatively uncontrolled conditions in this demonstration.
Your results cannot be displayed because you didn't complete all 120 trials.
If you want to complete all the trials and see your results, click FINISH.
8.7 Explain
explain_text
How Does the Locus of Attention Affect the Time Needed to Detect Visual Stimuli?
Attentional cuing—providing a cue about the location of an upcoming target stimulus—can be used to examine how the spatial location of a person's attention (the locus of attention) affects the speed with which the person can become aware of the target and respond to it.
In a typical experiment (Posner et al., 1978), the participant was instructed to fixate on a point at the center of a visual display (Time 1 in Figure 1a). One of three cues then appeared in the display for one second (Time 2): a left- or right-pointing arrow indicated that the participant should direct her attention to the corresponding side of the fixation point, because she'd been told that a target was likely to appear in that location; a plus sign was a neutral cue, indicating that the target was equally likely to appear in either location. Regardless of where she directed her attention, the participant was required to keep her gaze on the fixation point. The target then appeared (Time 3), and the participant had to press a button as soon as she saw it.
When the cue indicated that the participant should direct her attention to the left or the right, the target appeared on that side in 80% of the trials (these were called valid cues) and on the other side in 20% of the trials (invalid cues); when the cue was neutral, the target appeared equally often on either side.
Figure 1b shows that the time required to press the button—the response time—was significantly faster when the target followed a valid cue than when it followed an invalid cue, with the response time to targets following neutral cues somewhere in between. This indicates that detecting the target is significantly faster when it appears in an attended location than when it appears in an unattended location. It's as if an "attentional spotlight" is directed to the cued location, and this speeds perception.
In a typical experiment (Posner et al., 1978), the participant was instructed to fixate on a point at the center of a visual display (Time 1 in Figure 1a). One of three cues then appeared in the display for one second (Time 2): a left- or right-pointing arrow indicated that the participant should direct her attention to the corresponding side of the fixation point, because she'd been told that a target was likely to appear in that location; a plus sign was a neutral cue, indicating that the target was equally likely to appear in either location. Regardless of where she directed her attention, the participant was required to keep her gaze on the fixation point. The target then appeared (Time 3), and the participant had to press a button as soon as she saw it.
When the cue indicated that the participant should direct her attention to the left or the right, the target appeared on that side in 80% of the trials (these were called valid cues) and on the other side in 20% of the trials (invalid cues); when the cue was neutral, the target appeared equally often on either side.
Figure 1b shows that the time required to press the button—the response time—was significantly faster when the target followed a valid cue than when it followed an invalid cue, with the response time to targets following neutral cues somewhere in between. This indicates that detecting the target is significantly faster when it appears in an attended location than when it appears in an unattended location. It's as if an "attentional spotlight" is directed to the cued location, and this speeds perception.
8.8 Test - single choice
You must select an answer and then click SUBMIT before you can click proceed to the next screen.
test_single_choice
Select your answer to the question below. Then click SUBMIT.
Question
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Correct! Click EXPLAIN if you want to review this topic.
Incorrect.
The correct answer is D.
Click EXPLAIN if you want to review this topic.
The correct answer is D.
Click EXPLAIN if you want to review this topic.
8.9 Test - single choice
You must select an answer and then click SUBMIT before you can click proceed to the next screen.
test_single_choice
Select your answer to the question below. Then click SUBMIT.
Question
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Correct! Click EXPLAIN if you want to review this topic.
Incorrect.
The correct answer is С.
Click EXPLAIN if you want to review this topic.
The correct answer is С.
Click EXPLAIN if you want to review this topic.
8.10 Test - single choice
You must select an answer and then click SUBMIT before you can click proceed to the next screen.
test_single_choice
Select your answer to the question below. Then click SUBMIT.
Question
eJ51TNwvD8rZJbL6HKKCsgd6hPvo4cQcmVY6GvhWqAWK8rBo90pfNxgQhVs06U3a/nHEzb3Ywb90MzNL7D4HplGiuKgim4jV37OQf3RJtheteh+VQ3PQA5iFKcJeBtYOaFotLDgF1hRzvD5tS3tm1Z63NRVvQKbNQ3n1yLgZAeatkrv7IFyK0KiCNErUq8vuTvbLvQdS6FUep1jN9oFd2uyj0FG3Zj/ukpbGdJ5kdfuJ+USchMN4M+N+gFGWtgo9DHZrGNAXERoZZAhTznEzukyXlZsZ6kqUEfdnfI9hGc/z3N0gW5jekpv24G28XxvhbjSi44PBacfsiIb4mG8xHtqX13SJ2wwmwXdD3NKw3f2ZCljcphFnXwBlIEQK8zBHnriikc9VUUqOmdpiSnKeweA1a6qNBWOFQX4k2lYWWfWXm6RXKCUc0V8FW7n7e5gtt/BKDrgenE+BCDefF530hTr+BA4LEaGsU+fMRgIq8KeBGbVX3IuukF8sBNN7bvliSKyRBQSCm32+mkT00ZNLju7q4O6EziB9Fxh59b2h7+ee+2fENKDcHDdMfBnyHTt6crD6tbRIMuPlQ4x1SHJEPlNqN4LnSYeqHZMeSXZIBTVQRqUcV/2cwttBBA8a1cSbeCO13ueBM7OmkjhELRRU8ORzDIHj0/l8hz0RiNXJjuvsk3Bp5zFSsD6xnyJPeABPFJe9eRj3fxGRr/IJ3aZnqRTOJR4yAXmgyZkOdE5G5WXtbdkQCcMaSic/2l/DLPft/lQhxbto2IJ3A7ygjUI+xqQaI48FAfQsSc28U+M8maWKAe9kAr5psiKiArQx8rXw0s4S1eMdwtM7TErtHW0zvmFvWqaXc6qLtJChtBedMAin45I23D7J8r55x6kgAe5aC9zPqtCuQ/fyxMbH5cYCHPjMo9I2NnqhyuNt8B1fPhbOHIb62YiZDLUeUiiws7D+CvSL8kC9t2VG+nxmcL8y3ISjmGKwk7auGy9RAb1zz3M8EfGk8CsjilBX9K+gJT5/mk2yMbbfronuTO1slSTbcYHEhqhC3XYykBEMWpxCg1cnFrr1hQV9jT51SRMFhYNypEZkPwlczx0X2phIXTO6+kIAwds5p2ryLlzXwozE0UxkNX0tuaeJCA==Correct! Click EXPLAIN if you want to review this topic.
Incorrect.
The correct answer is C.
Click EXPLAIN if you want to review this topic.
The correct answer is C.
Click EXPLAIN if you want to review this topic.
8.11 Test - single choice
You must select an answer and then click SUBMIT before you can click proceed to the next screen.
test_single_choice
Select your answer to the question below. Then click SUBMIT.
Question
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Correct! Click EXPLAIN if you want to review this topic.
Incorrect.