Redundancy masking: The loss of repeated items in crowded peripheral vision

Abstract

Crowding is the deterioration of target identification in the presence of neighboring objects. Recent studies using appearance-based methods showed that the perceived number of target elements is often diminished in crowding. Here we introduce a related type of diminishment in repeating patterns (sets of parallel lines), which we term "redundancy masking." In four experiments, observers were presented with arrays of small numbers of lines centered at 10°eccentricity. The task was to indicate the number of lines. In Experiment 1, spatial characteristics of redundancy masking were examined by varying the inter-line spacing. We found that redundancy masking decreased with increasing inter-line spacing and ceased at spacings of approximately 0.25 times the eccentricity. In Experiment 2, we assessed whether the strength of redundancy masking differed between radial and tangential arrangements of elements as it does in crowding. Redundancy masking was strong with radially arranged lines (horizontally arranged vertical lines), and absent with tangentially arranged lines (vertically arranged horizontal lines). In Experiment 3, we investigated whether target size (line width and length) modulated redundancy masking. There was an effect of width: Thinner lines yielded stronger redundancy masking. We did not find any differences between the tested line lengths. In Experiment 4, we varied the regularity of the line arrays by vertically or horizontally jittering the positions of the lines. Redundancy masking was strongest with regular spacings and weakened with decreasing regularity. Our experiments show under which conditions whole items are lost in crowded displays, and how this redundancy masking resembles-and partly diverges from-crowded identification. We suggest that redundancy masking is a contributor to the deterioration of performance in crowded displays with redundant patterns.

Redundancy masking and the identity crowding debate

“…In the redundancy masking condition of this experiment, only the letter T was used, but data from subsequent experiments demonstrates that redundancy masking also occurs with other shapes, such as lines (Yildirim et al, 2020), and more complex letters, indicating that it is not an effect unique to T's.…”

Seven Myths on Crowding and Peripheral Vision

“…Yet unlike in crowding, all the numerals in the strings are unambiguous, and the difficulty is rather one of perceiving their correct number. Yildirim et al (2020) have called that phenomenon redundancy masking, which they argue is related to, but not the same as crowding. Note also the use of separators (Shaw, 1969;Estes & Wolford, 1971).…”

Hidden by bias: how standard psychophysical procedures conceal crucial aspects of peripheral visual appearance

“…While such contextual influences have beneficial effects, for example, by stabilizing perception, the introduced biases may conceal important aspects of target appearance. Here, we show how contextual influences affect the perception in stimuli susceptible to ‘redundancy masking’, the recently discovered phenomenon that entire items within repeating patterns are not reported 29 , 30 .…”

“…In redundancy masking, redundant elements in displays containing as few as three repeating elements are unavailable for conscious report (Fig. 1 a 29 , 30 ). For example, when asked to indicate the number of three closely-spaced identical elements presented in the visual periphery, the majority of observers reported only two elements (Fig.…”