Asymmetric Brightness Effects With Dark Versus Light Glare-Like Stimuli.

Yuki Kobayashi,Daniele Zavagno,Kazunori Morikawa

doi:10.1177/2041669521993144

Yuki Kobayashi, Daniele Zavagno + Show 1 more

Open Access

https://doi.org/10.1177/2041669521993144

Copy DOI

Abstract

The glare effect is a brightness illusion that has captured the attention of the vision community since its discovery. However, its photometrical reversal, which we refer to here as photometrical reversed glare (PRG) stimuli, remained relatively unexplored. We presented three experiments that sought to examine the perceived brightness of a target area surrounded by luminance gradients in PRG stimuli and compare them with conventional glare effect configurations. Experiment 1 measured the brightness of the central target area of PRG stimuli through an adjustment task; the results showed that the target appeared brighter than similar, comparative areas not surrounded by luminance gradients. This finding was unexpected given the recent report that PRG stimuli cause pupil dilation. Meanwhile, Experiments 2 and 3 implemented a rating task to further test the findings in Experiment 1. Again, the study found a robust brightening illusion in the target area of PRG stimuli in a wide range of target and background luminance. The results are discussed in comparison with the brightness enhancement of the glare effect.

Highlights

The glare effect is a brightness illusion that has captured the attention of the vision community since its discovery
In Experiment 1, we examined whether a dark area surrounded by decreasing gradients is perceived as darker and, if so, whether such illusion is accompanied by a perceptible lightness difference in a gray target patch embedded in such configurations
A two-tailed paired t-test showed a significant difference in brightness between the central areas of the photometrical reversed glare (PRG) and PRG-uniform stimuli—t (7) 1⁄4 4.58, p 1⁄4 .003, dz 1⁄4 1.62.1 A one-sample t-test showed that the adjusted luminance for the PRG stimulus was significantly higher than its physical luminance—65.0 cd/m2; t (7) 1⁄4 4.43, p 1⁄4 .003, dz 1⁄4 1.57

Summary

Introduction

The glare effect is a brightness illusion that has captured the attention of the vision community since its discovery. Agostini and Galmonte (2002) used glare and PRG stimuli to examine whether they affect lightness perception They introduced small gray targets at the center of the cross configurations (Figure 2), creating a novel pattern for a simultaneous lightness contrast illusion (SLC). Gori et al (2010) found that when the center of a glare-like stimuli appears even brighter because of dynamic presentation (Anstis et al, 2007; Gori & Stubbs, 2006), SLC enhancement gets stronger (i.e., the central gray patch appears even darker) They claimed that the higher brightness at the center of the glare stimulus causes SLC enhancement, supporting the high-perceptual-contrast hypothesis, which is essentially a percept–percept coupling type of account (Epstein, 1982)

Methods

Results

Conclusion