Figure 4.

Panel (a) shows how the spatial extent of crowding (deg) varies as a function of stimulus duration (msec). The spatial extent of crowding was defined as the separation between a target letter T and one of its four flanking Ts that allowed observers to identify the orientation of the target T at an accuracy of 62.5%. The contrast polarity of the target could be the same as, or opposite to that of the flankers. Panel (b) plots reading speed (wpm) as a function of eccentricity (deg), for text rendered as all white letters, all black letters, or interleaved white and black letters. Data shown in both panels represent the averaged values for the same three observers and are modified from Chung & Mansfield.²⁹ Error bars represent ± 1 S.E.M.