The Pupillary Light Response Reveals the Focus of Covert Visual Attention

Sebastiaan Mathot*, Lotje Van der Linden, Jonathan Grainger, Francoise Vitu

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

91 Citations (Scopus)
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Abstract

The pupillary light response is often assumed to be a reflex that is not susceptible to cognitive influences. In line with recent converging evidence, we show that this reflexive view is incomplete, and that the pupillary light response is modulated by covert visual attention: Covertly attending to a bright area causes a pupillary constriction, relative to attending to a dark area under identical visual input. This attention-related modulation of the pupillary light response predicts cuing effects in behavior, and can be used as an index of how strongly participants attend to a particular location. Therefore, we suggest that pupil size may offer a new way to continuously track the focus of covert visual attention, without requiring a manual response from the participant. The theoretical implication of this finding is that the pupillary light response is neither fully reflexive, nor under complete voluntary control, but is instead best characterized as a stereotyped response to a voluntarily selected target. In this sense, the pupillary light response is similar to saccadic and smooth pursuit eye movements. Together, eye movements and the pupillary light response maximize visual acuity, stabilize visual input, and selectively filter visual information as it enters the eye.

Original languageEnglish
Article numbere78168
Number of pages10
JournalPLoS ONE
Volume8
Issue number10
DOIs
Publication statusPublished - 29-Oct-2013
Externally publishedYes

Keywords

  • EYE-MOVEMENTS
  • SIZE
  • DILATION
  • SEARCH
  • REFLEX
  • MICROSTIMULATION
  • PUPILLOMETRY
  • STIMULATION
  • PERFORMANCE
  • DYNAMICS

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