Effects of visual and verbal presentation on cognitive load in vigilance, memory, and arithmetic tasks


  • This work was funded by the Stanford Regional Visual Analytics Center, through the U.S. Department of Energy's Pacific Northwest National Laboratory. Portions of this research were supported by NSF grants HHC 0905417, IIS-0725223, IIS-0855995, and REC 0440103. Our eye tracker was funded by the Stanford MediaX project and the Stanford School of Engineering. Some of the data from the aural presentation condition of all three experiments were presented at the Eye Tracking Research and Applications conference (Klingner, Kumar, & Hanrahan, 2008).
    The experiments described in this article were conducted in compliance with the policies of Stanford's institutional review board. All participants gave informed consent, and their rights and safety were protected.

Address correspondence to: Jeff Klingner, Gates Building Room 3B-396, Stanford, CA 94305-9035, USA. E-mail: klingner@stanfordalumni.org


Degree of pupil dilation has been shown to be a valid and reliable measure of cognitive load, but the effect of aural versus visual task presentation on pupil dilation is unknown. To evaluate effects of presentation mode, pupil dilation was measured in three tasks spanning a range of cognitive activities: mental multiplication, digit sequence recall, and vigilance. Stimuli were presented both aurally and visually, controlling for all known visual influences on pupil diameter. The patterns of dilation were similar for both aural and visual presentation for all three tasks, but the magnitudes of pupil response were greater for aural presentation. Accuracy was higher for visual presentation for mental arithmetic and digit recall. The findings can be accounted for in terms of dual codes in working memory and suggest that cognitive load is lower for visual than for aural presentation.