Abstract
In the visual periphery, observers can overestimate their performance – i.e. feel more confident than they 'should' – relative to central vision, termed "subjective inflation". However, until now subjective inflation has been demonstrated typically at one or two performance levels, such that performance is assumed to be 'matched' across center versus periphery if no significant difference is observed. Moreover, these effects have not been studied as a function of polar angle (e.g., vertical versus horizontal meridian). Here, we apply a new analytic approach to characterizing the relationship between performance and confidence across a wider range of performance levels ("metaperceptual function"), across both the horizontal and vertical meridians. Using a novel experimental paradigm, we calculate metaperceptual functions as a function of visual and polar angle to ask how subjective inflation magnitude changes by these factors. In a 2AFC luminance comparison task, observers report which of two flickering circular patches is brighter on average, plus decision confidence. In each trial, the patches vary in eccentricity (2 or 8°), relative luminance (i.e., mean luminance difference between the patches), overall luminance, and luminance variability; they vary block-wise by vertical/horizontal meridian placement. We record trial-by-trial choices, confidence ratings, and reaction times. For each subject, we then apply metaperceptual function analysis to determine probability of high confidence as a function of performance. Results suggest that while confidence covaries with performance as expected, there exist systematic differences in this relationship as a function of stimulus properties and polar angle. Specifically, peripheral inflation appears stronger at the vertical meridian than at the horizontal meridian. These findings demonstrate that our novel paradigm, plus the metaperceptual analytic approach, provides a powerful framework for characterizing the relationship between visual performance and confidence across condition, eccentricity, and polar angle, significantly contributing to knowledge of how visual confidence is generated.