Large Pupils Predict Goal-Driven Eye Movements

Sebastiaan Mathot*, Alisha Siebold, Mieke Donk, Francoise Vitu

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

21 Citations (Scopus)
133 Downloads (Pure)

Abstract

Here we report that large pupils predict fixations of the eye on low-salient, inconspicuous parts of a visual scene. We interpret this as showing that mental effort, reflected by a dilation of the pupil, is required to guide gaze toward objects that are relevant to current goals, but that may not be very salient. When mental effort is low, reflected by a constriction of the pupil, the eyes tend to be captured by high-salient parts of the image, irrespective of top-down goals. The relationship between pupil size and visual saliency was not driven by luminance or a range of other factors that we considered. Crucially, the relationship was strongest when mental effort was invested exclusively in eye-movement control (i.e., reduced in a dual-task setting), which suggests that it is not due to general effort or arousal. Our finding illustrates that goal-driven control during scene viewing requires mental effort, and that pupil size can be used as an online measure to track the goal-drivenness of behavior.

Original languageEnglish
Pages (from-to)513-521
Number of pages9
JournalJournal of Experimental Psychology. General
Volume144
Issue number3
DOIs
Publication statusPublished - Jun-2015
Externally publishedYes

Keywords

  • pupil size
  • mental effort
  • eye movements
  • saliency
  • goal-driven behavior
  • SACCADIC TARGET SELECTION
  • VISUAL-SEARCH
  • ATTENTION
  • SALIENCE
  • TIME
  • MODEL
  • PUPILLOMETRY
  • INHIBITION
  • ALLOCATION
  • RESPONSES

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