A perceptual-economy account for the inverted-optimal viewing position effect.

Abstract

In reading, fixation durations are longer when the eyes fall near the center of words than when fixation occurs toward the words' ends-the inverted-optimal viewing position (I-OVP) effect. This study assessed whether the I-OVP effect was based on the fixation position in the word or the fixation position in the visual stimulus. In Experiments 1-3, words were presented at variable locations within longer strings of symbols. On trials with short fixation durations, there were effects of fixation position in the string. When long fixations were made, there were effects of fixation position in the word. In Experiment 4, an I-OVP effect was found for meaningless number strings, and its strength depended on the task's processing demands. The findings show that (a) the I-OVP effect is unrelated to orthographic informativeness and (b) the eyes are not constrained to spend more time at the center of visual stimuli. These results support a perceptual-economy account: Fixations are held longer when the eyes are estimated to be at locations in words/stimuli in which greater amounts of information are anticipated. Implications for eye movements in reading are discussed.

Letter Visibility and the Optimal Viewing Position Effect of Isolated Connected and Un-Connected Letters in Arabic

“…Visual acuity limitations may explain the OVP eff ect. Previous research has argued that the decrease in visual acuity with retinal eccentricity contributes to the OVP eff ects of word recognition; this occurs because visual acuity decreases with greater lett er distance from the fi xation position, resulting in a loss of visual information (Brysbaert & Nazir, 2005;Nazir, 1991;Rayner, 2009;Vitu, Lancelin, & d'Unienville, 2007). It seems that the OVP eff ect is more evident in extrafoveal locations, with no OVP eff ects observed for foveal locations (Almabruk, Paterson, McGowan, & Jordan, 2011;Liu & Li, 2013).…”

Not fixating at the line of text comes at a cost

“…The perceptual-economy account advocates that fixations are held longer when the eyes are estimated to be at locations in words where greater amounts of information are anticipated (Vitu et al, 2007;Vitu et al, 2001). In reading, the horizontal center of a word is such an optimal location.…”

“…OVP effects were first reported for isolated words, which are more easily and more quickly identified when the eyes initially fixate near the center of the word (see Vitu, Lancelin & d'Unienville, 2007, for a review). As a relevant example, Kajii and Osaka (2000) investigated the OVP in horizontally and vertically presented Japanese words.…”

“…It has been argued that, for perceptual-economy reasons, fixations are held longer when the eyes are estimated to be at optimal locations where greater amounts of information are anticipated (Vitu et al, 2007;Vitu et al, 2001). On a more speculative note, Vitu and colleagues proposed that perceptual-economy principles may be universal in the sense that they may be at work in any task that involves visual information intake (Vitu et al, 2007).…”

“…On a more speculative note, Vitu and colleagues proposed that perceptual-economy principles may be universal in the sense that they may be at work in any task that involves visual information intake (Vitu et al, 2007). With regard to vertical landing positions in reading, optimality may be confined within the lower and upper boundaries of the text.…”