scholarly journals Dissociating proactive from reactive control in multiple-target visual search

2018 ◽  
Vol 18 (10) ◽  
pp. 982
Author(s):  
Eduard Ort ◽  
Johannes Fahrenfort ◽  
Michael Hanke ◽  
Falko Kaule ◽  
Reshanne Reeder ◽  
...  
2018 ◽  
Author(s):  
Joram van Driel ◽  
Eduard Ort ◽  
Johannes J. Fahrenfort ◽  
Christian N. L. Olivers

AbstractMany important situations require human observers to simultaneously search for more than one object. Despite a long history of research into visual search, the behavioral and neural mechanisms associated with multiple-target search are poorly understood. Here we test the novel theory that the efficiency of looking for multiple targets critically depends on the mode of cognitive control the environment affords to the observer. We used an innovative combination of EEG and eye tracking while participants searched for two targets, within two different contexts: Either both targets were present in the search display and observers were free to prioritize either one of them, thus enabling proactive control over selection; or only one of the two targets would be present in each search display, which requires reactive control to reconfigure selection when the wrong target is prioritized. During proactive control, both univariate and multivariate signals of beta-band (15–35 Hz) power suppression prior to display onset predicted switches between target selections. This signal originated over midfrontal and sensorimotor regions and has previously been associated with endogenous state changes. In contrast, imposed target selections requiring reactive control elicited prefrontal power enhancements in the delta/theta-band (2–8 Hz), but only after display onset. This signal predicted individual differences in associated oculomotor switch costs, reflecting reactive reconfiguration of target selection. The results provide compelling evidence that multiple target representations are differentially prioritized during visual search, and for the first time reveal distinct neural mechanisms underlying proactive and reactive control over multiple-target search.Significance StatementSearching for more than one object in complex visual scenes can be detrimental for search performance. While perhaps annoying in daily life, this can have severe consequences in professional settings such as medical and security screening. Previous research has not yet resolved whether multiple-target search involves changing priorities in what people attend to, and how such changes are controlled. We approached these questions by concurrently measuring cortical activity and eye movements using EEG and eye tracking, while observers searched for multiple possible targets. Our findings provide the first unequivocal support for the existence of two modes of control during multiple-target search, which are expressed in qualitatively distinct time-frequency signatures of the EEG both before and after visual selection.


2015 ◽  
Vol 2 (1) ◽  
pp. 121-128 ◽  
Author(s):  
Stephen R. Mitroff ◽  
Adam T. Biggs ◽  
Matthew S. Cain

Visual search—the ability to locate visual targets among distractors—is a fundamental part of professional performance for many careers, including radiology, airport security screening, cytology, lifeguarding, and more. Successful execution of visual search in these settings is critically important because the consequences of a missed target can be horrific. Unfortunately, many of these professions place high demands on the people performing the searches, and either the task or the environment (or both) could lead to significant errors. One known source of error that exists across many fields is “multiple-target visual search” errors—a target is less likely to be detected if another target was already found in the same search than if the target was the only one present. These errors have proven to be stubborn and not easily eliminated. This article offers a brief overview of the existing research on multiple-target visual search errors and discusses possible policy implications of the errors for airport security screening. The policy suggestions are based on empirical research, with the hope of providing food for thought on using scientific data and theory to improve performance. Specifically, three policy suggestions are raised: shift screening to a remote location away from the checkpoint, reduce the number of prohibited items to lessen the searchers’ cognitive burden, and emphasize search consistency in the training process. Note that the focus here is on airport security screening, as this is a domain most readers can relate to, but the suggestions can equally apply to many search environments.


2015 ◽  
Vol 77 (3) ◽  
pp. 844-855 ◽  
Author(s):  
Adam T. Biggs ◽  
Stephen H. Adamo ◽  
Emma Wu Dowd ◽  
Stephen R. Mitroff

2014 ◽  
Vol 14 (10) ◽  
pp. 1195-1195
Author(s):  
N. Attar ◽  
C.-C. Wu ◽  
M. Pomplun

2014 ◽  
Vol 45 (3) ◽  
pp. 528-533 ◽  
Author(s):  
Kait Clark ◽  
Matthew S. Cain ◽  
R. Alison Adcock ◽  
Stephen R. Mitroff

2017 ◽  
Vol 17 (10) ◽  
pp. 79
Author(s):  
Stephen Adamo ◽  
Joseph Nah ◽  
Andrew Collegio ◽  
Paul Scotti ◽  
Sarah Shomstein

2012 ◽  
Vol 12 (9) ◽  
pp. 1010-1010 ◽  
Author(s):  
M. S. Cain ◽  
S. H. Adamo ◽  
S. R. Mitroff

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