Anishka Yerabothu¹, Nicole Oppenheimer², Alex White¹; ¹Barnard College, Columbia University, ²Rutgers University

Crowding refers to a phenomenon where neighboring objects interfere with the perception of a central target. An interesting property of crowding is that it is asymmetric across the left and right hemifields for certain stimuli. Previous research, including our own, has found that letters crowd each other less in the right visual field than the left. We investigated how the hemifield asymmetry for letters compares to that of pseudo-letters with matched visual features. In one experiment, participants identified a central stimulus within a set of three stimuli of the same type (letters or pseudo-letters), positioned at 4° eccentricity. Crowding was assessed by fitting full psychometric functions to extract critical spacing thresholds. In terms of those thresholds, there was a more pronounced hemifield asymmetry (left > right) for letter recognition compared to pseudo-letter recognition. In a separate experiment, central target letters were flanked by either other letters or by pseudo-letters. Crowding was less pronounced when the flankers were letters than pseudo-letters, but the hemifield asymmetry was strong in both cases. These results suggest that there is a unique advantage for processing strings of letters in the right visual field. That advantage could reduce interference between the letters within words, when they are presented in locations processed by the language-dominant left cerebral hemisphere.