Abstract
Object recognition can be unfavorably affected by placing other objects nearby. This crowding phenomenon is a major limiting factor in peripheral letter recognition. Previous studies (e.g. Macedo et al., 2008; Rosenberg et al, ARVO2011) showed a connection between retinal image motion and enhanced isolated target recognition. Here, we examine how adding motion cues such as jiggling motion influences the effect of crowding on letter recognition in peripheral vision. "Jiggling" is defined as a rapid displacement along a specified direction with a fixed magnitude, repeated at a given temporal frequency. We examined four configurations of jiggling motion: target motion only, flanker motion only, the same motion in both the target and flankers, and two orthogonal motions applied to the target and flankers, respectively. Five normally sighted adults participated. Strings of three random letters with 1° print size (corresponding to 100% accuracy of isolated letter recognition) and standard spacing (1.16×x-width) were presented at 10° eccentricity on the right or left of a fixation point for an exposure duration of 188ms. For each motion configuration, we measured accuracy for identifying the middle letters for two motion directions (horizontal and vertical), two temporal frequencies (47 and 94ms/cycle), and three levels of motion amplitude (0° (stationary), 0.1°, and 0.2°). Averaged across observers, letter recognition accuracy was 54% for the stationary condition. Accuracy increased to 76% (p<0.0005) when motion was applied to the target only (irrespective of motion direction, amplitude, and frequency), and remained the same for the three other motion configurations (mean accuracy=52%). A control experiment revealed that the observed improvement was not due to the fact that the jiggling target covered larger area or stretched the target-flanker distance. We conclude that adding jiggling motion to the target can disrupt the adverse interaction between letters (crowding) and can significantly improve letter recognition in the periphery.
Meeting abstract presented at VSS 2012