Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2022 Jun;51(6):370-387.
doi: 10.1177/03010066221094757. Epub 2022 May 2.

The influence of pupil responses on subjective brightness perception

I K Wardhani  1 , C N Boehler  2 , S Mathôt  3
Affiliations

The influence of pupil responses on subjective brightness perception

I K Wardhani et al. Perception. 2022 Jun.

Abstract

When the pupil dilates, the amount of light that falls onto the retina increases. However, in daily life, this does not make the world look brighter. Here we asked whether pupil size (resulting from active pupil movement) influences subjective brightness in the absence of indirect cues that, in daily life, support brightness constancy. We measured the subjective brightness of a tester stimulus relative to a referent as a function of pupil size during tester presentation. In Experiment 1, we manipulated pupil size through a secondary working-memory task (larger pupils with higher load and after errors). We found some evidence that the tester was perceived as darker, rather than brighter, when pupils were larger. In Experiment 2, we presented a red or blue display (larger pupils following red displays). We again found that the tester was perceived as darker when pupils were larger. We speculate that the visual system takes pupil size into account when making brightness judgments. Finally, we highlight the challenges associated with manipulating pupil size. In summary, the current study (as well as a recent pharmacological study on the same topic by another team) is intriguing first steps towards understanding the role of pupil size in brightness perception.

Keywords: luminance; psychosensory pupil reflex; pupil light reflex; pupil size; pupillometry; subjective brightness perception.

PubMed Disclaimer

Conflict of interest statement

Declaration of Conflicting Interests: The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Figures

Figure 1.
Figure 1.
Experimental task of Experiment 1.
Figure 2.
Figure 2.
Plots of pupil size by memory load.
Figure 3.
Figure 3.
Brightness judgment differences by memory load. Participants’ subjective brightness judgment of the tester stimulus was fitted with a sigmoid curve. We found no difference in the brightness judgment between the low- and high-load conditions.
Figure 4.
Figure 4.
Plots of pupil size by performance feedback.
Figure 5.
Figure 5.
Brightness judgment by performance feedback.
Figure 6.
Figure 6.
Isoluminance calibration and the experimental task of Experiments 2a and 2b.
Figure 7.
Figure 7.
Plots of calibrated pupil size in Experiments 2a and 2b.
Figure 8.
Figure 8.
Plots of experimental pupil size in Experiment 2a.
Figure 9.
Figure 9.
Plots of experimental pupil size in Experiment 2b.
Figure 10.
Figure 10.
Brightness judgment as a function of display colour.
Figure 11.
Figure 11.
Results summary.
See this image and copyright information in PMC

References

    1. Ajasse S., Benosman R. B., Lorenceau J. (2018). Effects of pupillary responses to luminance and attention on visual spatial discrimination. Journal of Vision, 18, 6. 10.1167/18.11.6 - DOI - PubMed
    1. Berson D. M., Dunn F. A., Takao M. (2002). Phototransduction by retinal ganglion cells that set the circadian clock. Science, 295, 1070–1073. 10.1126/science.1067262 - DOI - PubMed
    1. Bombeke K., Duthoo W., Mueller S. C., Hopf J.-M., Boehler C. N. (2016). Pupil size directly modulates the feedforward response in human primary visual cortex independently of attention. Neuroimage, 127, 67–73. 10.1016/j.neuroimage.2015.11.072 - DOI - PubMed
    1. Bradley M. M., Miccoli L., Escrig M. A., Lang P. J. (2008). The pupil as a measure of emotional arousal and autonomic activation. Psychophysiology, 45, 602–607. 10.1111/j.1469-8986.2008.00654.x - DOI - PMC - PubMed
    1. Braem S., Coenen E., Bombeke K., van Bochove M. E., Notebaert W. (2015). Open your eyes for prediction errors. Cognitive, Affective & Behavioral Neuroscience, 15, 374–380. 10.3758/s13415-014-0333-4 - DOI - PubMed

LinkOut - more resources