title: Analysis of microsaccades and pupil dilation reveals a common decisional origin during visual search.
abstract: During free viewing visual search, observers often refixate the same locations several times before and after target detection is reported with a button press. We analyzed the rate of microsaccades in the sequence of refixations made during visual search and found two important components. One related to the visual content of the region being fixated; fixations on targets generate more microsaccades and more microsaccades are generated for those targets that are more difficult to disambiguate. The other empathizes non-visual decisional processes; fixations containing the button press generate more microsaccades than those made on the same target but without the button press. Pupil dilation during the same refixations reveals a similar modulation. We inferred that generic sympathetic arousal mechanisms are part of the articulated complex of perceptual processes governing fixational eye movements.
authors: School of Optometry, University of California, Berkeley, CA, United States. Electronic address: claudiop@berkeley.edu.
authors: Claudio M
authors: CM
authors: Privitera
authors: School of Optometry, University of California, Berkeley, CA, United States.
authors: Thom
authors: T
authors: Carney
authors: School of Optometry, University of California, Berkeley, CA, United States.
authors: Stanley
authors: S
authors: Klein
authors: Intelligent Systems and Planning, Teledyne Scientific Company, Durham, NC, United States.
authors: Mario
authors: M
authors: Aguilar
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001288:Attention / Q000502:physiology; D005260:Female; D005403:Fixation, Ocular / Q000502:physiology*; D006801:Humans; D008297:Male; D008390:Markov Chains; D008875:Middle Aged; D010775:Photic Stimulation / Q000379:methods; D011680:Pupil / Q000502:physiology*; D012438:Saccades / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*; D055815:Young Adult
keywords: Microsaccades; Pupil; Refixations; Visual search