Universität zu Köln

Brocher, Andreas, Harbecke, Raphael, Graf, Tim, Memmert, Daniel and Huettermann, Stefanie (2018). <bold>Using task effort and pupil size to track covert shifts of visual attention independently of a pupillary light reflex</bold>. Behav. Res. Methods, 50 (6). S. 2551 - 2568. NEW YORK: SPRINGER. ISSN 1554-3528

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Abstract

We tested the link between pupil size and the task effort involved in covert shifts of visual attention. The goal of this study was to establish pupil size as a marker of attentional shifting in the absence of luminance manipulations. In three experiments, participants evaluated two stimuli that were presented peripherally, appearing equidistant from and on opposite sides of eye fixation. The angle between eye fixation and the peripherally presented target stimuli varied from 12.5 degrees to 42.5 degrees. The evaluation of more distant stimuli led to poorer performance than did the evaluation of more proximal stimuli throughout our study, confirming that the former required more effort than the latter. In addition, in Experiment 1 we found that pupil size increased with increasing angle and that this effect could not be reduced to the operation of low-level visual processes in the task. In Experiment 2 the pupil dilated more strongly overall when participants evaluated the target stimuli, which required shifts of attention, than when they merely reported on the target's presence versus absence. Both conditions yielded larger pupils for more distant than for more proximal stimuli, however. In Experiment 3, we manipulated task difficulty more directly, by changing the contrast at which the target stimuli were presented. We replicated the results from Experiment 1 only with the high-contrast stimuli. With stimuli of low contrast, ceiling effects in pupil size were observed. Our data show that the link between task effort and pupil size can be used to track the degree to which an observer covertly shifts attention to or detects stimuli in peripheral vision.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Brocher, Andreas UNSPECIFIED UNSPECIFIED UNSPECIFIED Harbecke, Raphael UNSPECIFIED UNSPECIFIED UNSPECIFIED Graf, Tim UNSPECIFIED UNSPECIFIED UNSPECIFIED Memmert, Daniel UNSPECIFIED UNSPECIFIED UNSPECIFIED Huettermann, Stefanie UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-163506
DOI:	10.3758/s13428-018-1033-8
Journal or Publication Title:	Behav. Res. Methods
Volume:	50
Number:	6
Page Range:	S. 2551 - 2568
Date:	2018
Publisher:	SPRINGER
Place of Publication:	NEW YORK
ISSN:	1554-3528
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language MEMORY STRENGTH; PROCESSING LOAD; RESPONSES; FOCUS; EYE; RECOLLECTION; FAMILIARITY; ALLOCATION; MOVEMENT Multiple languages Psychology, Mathematical; Psychology, Experimental Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/16350