Figure 2.

Stimulus size affects perceived asymmetries between dark and bright afterimages. A, Pedestal nulling paradigm consisting of an afterimage-inducing bright or dark disk followed by a luminance pedestal for 0.4 s; subjects were asked whether the post-stimulus period before the mask was perceived as brighter, darker, or the same as the background. B, Quick psychometric functions and their Bayesian posterior distributions for threshold and slope (inset, crosses indicate ±95% CI) for the pedestal contrast. C, Tuning curves for the null contrast of bright and dark afterimages across size, along with individual subject grouped scatter plots at each size (gray lines connect the bright and dark points for each subject). D, Top, Psychophysical paradigm for duration measurement. Bottom, Mean afterimage duration tuning curves and subject scatterplots for dark and bright stimuli. E, Top, Psychophysical paradigm for latency measurement. Bottom, Mean latency tuning curves and subject scatterplots for Δt mask thresholds between bright and dark afterimages. N = 8 subjects. Error bars indicate ±1 SEM. *p < 0.05. **p < 0.01. ***p < 0.001.