Flexibility in the Perceptual Span during Reading: Evidence from Mongolian

Abstract

Readers can acquire useful information from only a narrow region of text on each fixation (the perceptual span), which extends asymmetrically in the direction of reading. Studies with bilingual readers additionally show this asymmetry reverses with changes in horizontal reading direction. However, little is known about perceptual span flexibility following orthogonal (vertical versus horizontal) changes in reading direction, due to scarcity of vertical writing systems and because changes in reading direction often are confounded with text orientation. Accordingly, we assessed effects in a language (Mongolian) that avoids this confound and which conventionally is read vertically but can be read horizontally. Sentences were presented normally or in a gaze-contingent paradigm in which a restricted region of text was displayed normally on each fixation and other text degraded. Perceptual span effects on reading rates were similar in both reading directions. The findings therefore provide a unique (non-confounded) demonstration of perceptual span flexibility.