The central-peripheral dichotomy and metacontrast masking

Abstract

According to the central-peripheral dichotomy (CPD), feedback from higher to lower cortical areas along the visual pathway to aid recognition is weaker in the more peripheral visual field. Metacontrast masking is predominantly a reduced visibility of a brief target by a brief and spatially adjacent mask when the mask succeeds rather than precedes or coincides with the target. If this masking works mainly by interfering with the feedback mechanisms for target recognition, then, by the CPD, this masking should be weaker at more peripheral visual locations. We extended the metacontrast masking at fovea by Enns and Di Lollo to visual field eccentricities 1[Formula: see text], 3[Formula: see text], and 9[Formula: see text]. Relative to the target’s onset, the mask appeared at a stimulus onset asynchrony (SOA) of [Formula: see text], 0, 50, 92, or 142 milliseconds (ms). Enlarged stimuli were used for larger eccentricities to equalize target discrimination performance across eccentricities as best as possible for zero SOA and when SOA was too long for substantial masking. At each eccentricity, the masking was weakest at 0 or [Formula: see text] ms SOA, strongest at 50 ms SOA, and weakened with larger (positive) SOAs. Consistent with the CPD, larger eccentricities presented weaker maskings at all nonzero, and particularly the positive, SOAs.

Need for cross-level iterative re-entry in models of visual processing

“…More evidence along these lines has been reported by Lamme, Zipser, and Spekreijse ( 2002 ) and by Supèr, Spekreijse, and Lamme ( 2001 ), who found that feedback from extrastriate areas was critical for the stimuli to reach consciousness. Furthermore, Zhaoping and Liu ( 2022 ) found that metacontrast masking is weaker for stimuli displayed in the peripheral retina where feedback from higher to lower brain regions is thought to be weaker. Clearly, metacontrast masking cannot be wholly explained in terms of feed-forward processes.…”