Not fixating at the line of text comes at a cost

Attention, Perception, & Psychophysics, Nov 2013

Previous research on eye guidance in reading has investigated systematic tendencies with respect to horizontal fixation locations on letters within words and the relationship between fixation location in a word and the duration of the fixation. The present study investigates where readers place their eyes vertically on the line of text and how vertical fixation location is related to fixation duration. Analyses were based on a large corpus of eye movement recordings from single-sentence reading. The vertical preferred viewing location was found to be within the vertical extent of the font, but fixations beyond the vertical boundaries of the text also frequently occurred. Analyzing fixation duration as a function of vertical fixation location revealed a vertical optimal viewing position (vOVP) effect: Fixations were shortest when placed optimally on the line of text, and fixation duration gradually increased for fixations that fell above or below the line of text. The vOVP effect can be explained by the limits of visual resolution along the vertical meridian. It is concluded that vertical and horizontal landing positions in single-sentence reading are associated with differences in fixation durations in opposite ways.

A PDF file should load here. If you do not see its contents the file may be temporarily unavailable at the journal website or you do not have a PDF plug-in installed and enabled in your browser.

Alternatively, you can download the file locally and open with any standalone PDF reader:

http://link.springer.com/content/pdf/10.3758%2Fs13414-013-0581-3.pdf

Not fixating at the line of text comes at a cost

Atten Percept Psychophys Not fixating at the line of text comes at a cost Antje Nuthmann 0 1 0 A. Nuthmann Center for Interdisciplinary Research (ZiF), Bielefeld University , Bielefeld , Germany 1 A. Nuthmann ( 2 ) Psychology Department, University of Edinburgh , 7 George Square, Edinburgh EH8 9JZ , UK Previous research on eye guidance in reading has investigated systematic tendencies with respect to horizontal fixation locations on letters within words and the relationship between fixation location in a word and the duration of the fixation. The present study investigates where readers place their eyes vertically on the line of text and how vertical fixation location is related to fixation duration. Analyses were based on a large corpus of eye movement recordings from single-sentence reading. The vertical preferred viewing location was found to be within the vertical extent of the font, but fixations beyond the vertical boundaries of the text also frequently occurred. Analyzing fixation duration as a function of vertical fixation location revealed a vertical optimal viewing position (vOVP) effect: Fixations were shortest when placed optimally on the line of text, and fixation duration gradually increased for fixations that fell above or below the line of text. The vOVP effect can be explained by the limits of visual resolution along the vertical meridian. It is concluded that vertical and horizontal landing positions in singlesentence reading are associated with differences in fixation durations in opposite ways. Reading; Eye movements; Vertical fixation positions; Preferred viewing location; Fixation durations - When reading, we move our eyes across the page of text, mainly because of visual acuity limitations. Fine visual discriminations can be made only within the foveal region of the visual field, typically defined as the central 2 of vision. Eye movements during reading are generally considered to be the result of two classes of decisions, one spatial (where to move the eyes) and one temporal (when to move the eyes). The temporal aspect of eye movement behavior, the when decision, is captured by fixation-duration measures. The durations of individual fixations have been found to reflect ongoing perceptual and cognitive activity, providing a powerful method for investigating underlying perceptual and cognitive processes (Rayner, 1998). Concerning the spatial aspect of eye guidance in reading, there are several welldocumented findings related to landing positions in words (see Vitu, 2011, for a review). First of all, there are systematic tendencies with respect to where the eyes typically land within a word (the preferred viewing location [PVL]). In addition, landing position influences the likelihood of within-word refixations (the optimal viewing position [OVP] effect) and the duration of fixations (the inverted OVP [IOVP] effect). Landing positions of forward saccades into words tend to cluster at word center or slightly left of it, honoring the PVL (Rayner, 1979). For words of a given length, the distribution of landing positions resembles a truncated Gaussian distribution, and the PVL may be indexed by the mean of the fitted normal curve. The phenomenon has been replicated many times (e.g., McConkie, Kerr, Reddix & Zola, 1988; Nuthmann, Engbert & Kliegl, 2005; Vitu, McConkie, Kerr & ORegan, 2001). The variance in landing positions around word center is thought to be due to visuomotor constraints (McConkie et al., 1988). The observation of a PVL has been taken as strong evidence for word-based eye guidance (see Vitu, 2011, for critical discussion). 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. In both conditions, word recognition was best when the word center was fixated. Performance was generally better for horizontal words than for vertical words, which is in line with the results in Weymouth et al. (1928). Collectively, the results from single-word reading studies suggest that visual acuity is a major determinant of the OVP phenomenon. In text reading, a related effect has been described as the refixation probability OVP effect. The likelihood of making more than one fixation on a word before moving to another word is lower when the eyes initially fixate the middle of the word than when they first fixate the beginning or end of the word (e.g., McConkie, Kerr, Reddix, Zola & Jacobs, 1989; Nuthmann et al., 2005; Vitu et al., 2001). The occurrence of refixations is related not only to visual acuity constraints, but also to ongoing processing demands (McConkie et al., 1989). Given these findings from single-word and text reading studies, word center is thought to be the optimal position for word proces (...truncated)


This is a preview of a remote PDF: http://link.springer.com/content/pdf/10.3758%2Fs13414-013-0581-3.pdf

Antje Nuthmann. Not fixating at the line of text comes at a cost, Attention, Perception, & Psychophysics, 2013, pp. 1604-1609, Volume 75, Issue 8, DOI: 10.3758/s13414-013-0581-3