onset of the stimuli. SOA 400. SOA 800. CONCLUSION: Giving participants extra
time to process the background still shows a cueing effect although there is NO ...
INN VISUAL ISUAL SEARCH EARCH, DO O AVERAGE VERAGE FEATURES EATURES
OF OF A A SCENE CENE GUIDE UIDE 1 1,2 1,2 Stephen Flusberg , Melina A. Kunar , Jeremy M. Wolfe
INTRODUCTION
1
CONTEXTUAL CUEING IN VISUAL SEARCH: RTs are faster on trials where the spatial layout is predictive of target location and is repeated over time than on trials where the spatial layout is not predictive (Chun & Jiang, 1998) Repeated predictive background scenes also lead to faster RTs when the spatial layout is kept constant (DiMase & Chun, 2004)
QUESTIONS: 1)
R I
GENERAL CONCLUSIONS
TAS
Harvard Medical school
EXPERIMENT 3
CAN BACKGROUND FEATURES CUE TARGET LOCATION? IS THIS ATTENTIONAL GUIDANCE?
DOES EXTRA TIME TO PROCESS THE BACKGROUND LEAD TO ATTENTIONAL GUIDANCE?
LOOK, THIS HAS TO WORK IF WE TRY HARD ENOUGH!
Predictive backgrounds speed RTs but do not to seem guide attention towards the target. If they did, search would be more efficient. Why not? Maybe guidance by background color is just slow?
8 colors: 4 Predictive, 4 Random
1)
TIME 1400
Preview scene and color for 400 or 800 msec prior to the onset of the stimuli
1300 1200 1100
CUEING EFFECT for both set sizes
1000
700
Predictive 8 Predictive 12 Random 8 Random 12
Predictive RT < Random RT
600 1
2
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5
6
7
There was an SOA of 1500 msec between background onset and stimuli onset
2) Participants were explicitly informed which 4 of the 8 colors would be predictive AND exactly which location they would predict.
900 800
SOA 400
REACTION TIME
SOA 800
REACTION TIME
80
SLOPE
Predictive Random
70
40
No GUIDANCE EFFECT
30 20
Predictive 8 Predictive 12 Random 8 Random 12
1400 1300
Predictive 8 Predictive 12 Random 8 Random 12
1400 1300
Predictive 8 Predictive 12 Random 8 Random 12
1400 1300
1200
1200
1100
1100
1000
1000
900
900
800
800
700
700
600
600
HUGE CUEING EFFECT for both set sizes
1100
10 0
1
2
3
4
5
6
7
8
Epoch
1
We replicated this experiment using different cues (background texture, stimuli color) and stimuli (vertical and horizontal lines) and found the same results
512 mixed block trials divided into 8 epochs of 64 trials
900 800 700 600
CUEING EFFECT: Shown when Predictive RTs < Random RTs
2) GUIDANCE EFFECT: Shown when Predictive slopes < Random slopes. (”Perfect” guidance would yield zero slope.)
4
5
TEXTURE
LINE STIMULI
CONCLUSION: Background features can cue target location, but this is NOT due to attentional guidance
7
1
8
2
3
4
5
6
7
3
4
5
6
7
8
8
Epoch
SLOPE
80
Predictive Random
70 60
No GUIDANCE EFFECT for either SOA
80
80
Predictive Random
70
60
50
50
40
40
30
30
20
20
10
10 0
1
2
3
4
5
6
7
8
Predictive Random
70
60
Epoch
STIMULI COLOR ONLY
6
2
Epoch
Epoch
0
In epoch 8, all trials are randomized, so features that had cued target location are no longer predictive
3
SLOPE
Although it looks like there may be some guidance at SOA 400, this is not reliable and does not replicate
In epochs 1-7, half of the trials are predictive and half are random
2
3) Moreover, we have found a contextual cueing effect using tasks that do not require more attentional guidance (e.g. efficient single feature task)
1000
1
In our hands, contextual cueing speeds RTs.
2) We have not found contextual “guidance” in the form of a reduction in slopes across contextual cueing experiments
1200
CUEING EFFECT for all conditions except SOA 800 set size 12
60 50
1)
1)
8
2 Types of trials:
Data from the last 3 predictive epochs (5-7) were collapsed and Predictive vs. Random trials were compared (see Chun & Jiang, 1998)
Actually, we find similar results with CONTEXTUAL CUEING.
Epoch
Search Task: search for a rotated target T among distractor L’s
RANDOM: background feature does not cue target location
2) These features do not guide attention in a way that makes search more efficient unless there is time to process the background and the instructions are made explicit
Experiment 1 was replicated with 2 differences:
Set sizes 8 and 12
REACTION TIME
PREDICTIVE: background feature (e.g. color) cues exact target location across set size
1) Average features of a scene lead to modestly faster RTs when those features predict target location
EXPERIMENT 2
2) If so, is this a form of attentional guidance?
GENERAL METHODS
VE
EXPERIMENT 1
Scene color is the predictive cue
If the background predicts target location, are RTs speeded, even when there is no meaningful spatial information?
Brigham and Women’s Hospital
2
ATTENTION TTENTION?
BIG GUIDANCE EFFECT (though far from perfect)
50
REFERENCES
40 30 20
1)
Chun, M. M., & Jiang, Y. (1998). Contextual cueing: Implicit learning and memory of visual context guides spatial attention. Cognitive Psychology, 36, 28-71.
2)
DiMase, J. S., & Chun, M. M. (2004). Contextual cueing by realworld scenes [Abstract]. Journal of Vision, 4(8), 259a.
10 0
1
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5
6
7
8
Epoch
1
2
3
4
5
6
7
8
Epoch
CONCLUSION: Giving participants extra time to process the background still shows a cueing effect although there is NO attentional guidance
CONCLUSION: You can get guidance using these stimuli, BUT apparently you need to tell participants exactly where to look them and give them time.
This work was funded by the National Institute of Mental Health Special thanks to Jeremy Wolfe, Todd Horowitz, and Melina Kunar For more information, please contact us at
[email protected]
