Abstract
Does crowding affect apparent size? Korte (1923) and Liu & Arditi (1999) reported that a crowded string of letters appears shorter in length, possibly abbreviated, with letters missing. We present three rectangles, a target between flankers, all 1 deg high arranged horizontally, 10 deg to the right of fixation. The flankers are 1 deg wide. We tested several target widths: 0.75, 1.0 and 1.25 deg. Target-flanker spacing is 1.25 deg, center to center. We also tested without flankers. A reference rectangle is always present 5 deg above the target object, beyond the range of crowding. While maintaining fixation, the observer adjusts the width of this reference to match the apparent width of the target object. Relative to the unflanked condition, flankers decreased the apparent width of the target by 19% when the flankers were narrower and increased by 9% when the flankers were wider than the target. Thus, the apparent width of the target is a weighted average that includes the flankers. This is size pooling.