Evaluating Effects of Divided Hemispheric Processing on Word Recognition in Foveal and Extrafoveal Displays: The Evidence from Arabic

Background: Previous studies have claimed that a precise split at the vertical midline of each fovea causes all words to the left and right of fixation to project to the opposite, contralateral hemisphere, and this division in hemispheric processing has considerable consequences for foveal word recognition. However, research in this area is dominated by the use of stimuli from Latinate languages, which may induce specific effects on performance. Consequently, we report two experiments using stimuli from a fundamentally different, non-Latinate language (Arabic) that offers an alternative way of revealing effects of split-foveal processing, if they exist. Methods and Findings: Words (and pseudowords) were presented to the left or right of fixation, either close to fixation and entirely within foveal vision, or further from fixation and entirely within extrafoveal vision. Fixation location and stimulus presentations were carefully controlled using an eye-tracker linked to a fixation-contingent display. To assess word recognition, Experiment 1 used the Reicher-Wheeler task and Experiment 2 used the lexical decision task. Results: Performance in both experiments indicated a functional division in hemispheric processing for words in extrafoveal locations (in recognition accuracy in Experiment 1 and in reaction times and error rates in Experiment 2) but no such division for words in foveal locations. Conclusions: These findings from a non-Latinate language provide new evidence that although a functional division i

Word Recognition and Reading in Arabic

The thesis reports six experiments investigating word recognition and reading in Arabic. Experiment 1 looked at the word superiority effect in Arabic word recognition using brief presentations of stimuli (five-letter real words, pseudo-words, non-words, and inverted real words) in a Reicher-Wheeler task. The results of this experiment showed advantages for the recognition of words over pseudo-words and illegal non-words, and for pseudo-words over illegal non-words. Experiment 2 was a follow-up experiment that also examined the word superiority effect in Arabic by using the lexical decision task. In this experiment, participants viewed briefly presented real words and legal non-words, with the results showing that Arabic real words were recognised quicker and more accurately than non-words. Experiment 3 investigated the landing position effects for three, five, and seven letter words in Arabic using eye movements while reading. The results showed that the preferred viewing location (PVL) is at the right of centre of words in Arabic, similar to that for Hebrew. Experiment 4 re-examined the optimal viewing position in Arabic word recognition using five-letter Arabic words and non-words in a lexical decision task. The results showed that participants recognised words most quickly and most accurately when fixating inter-letter locations at the middle of words, indicating that the OVP for Arabic word recognition is at a word’s centre. Experiment 5 used the Reicher-Wheeler task and Experiment 6 used the lexical decision task to re-examine the claim that an anatomical division in the human fovea has consequences for word recognition. The findings revealed the superiority of the right visual field for words displayed outside the foveal and no asymmetries for words displayed within foveal vision. Thus far the research has made an important advance on our understanding of processes involved in Arabic word recognition by revealing that word superiority and pseudo-word superiority effects similar to those reported in Latinate languages are also observed in Arabic, and that the OVP effect in Arabic differs from that found in English. The reading results indicate that, similar to other languages, parafoveal word length information is used to guide saccade targeting in Arabic

Effects of Word Length on Eye Movement Control: The Evidence from Arabic

The finding that word length plays a fundamental role in determining where and for how long readers fixate within a line of text has been central to the development of sophisticated models of eye movement control. However, research in this area is dominated by the use of Latinate languages (e.g., English, French, German) and little is known about eye movement control for alphabetic languages with very different visual characteristics. To address this issue, the present experiment undertook a novel investigation of the influence of word length on eye movement behavior when reading Arabic. Arabic is an alphabetic language that not only is read from right-to-left but has visual characteristics fundamentally different from Latinate languages, and so is ideally-suited to testing the generality of mechanisms of eye movement control. The findings reveal that readers were more likely to fixate and refixate longer words, and also that longer words tended to be fixated for longer. In addition, word length influenced the landing positions of initial fixations on words, with the effect that readers fixated the center of short words and fixated closer to the beginning letters for longer words, and the location of landing positions affected both the duration of the first fixation and probability of refixating the word. The indication now, therefore, is that effects of word length are a widespread and fundamental component of reading and play a central role in guiding eye-movement behavior across a range of very different alphabetic systems

Reading direction and the central perceptual span : evidence from Arabic and English

In English and other alphabetic languages read from left to right, useful information acquired during each fixational pause is generally reported to extend much further to the right of each fixation than to the left. However, the asymmetry of the perceptual span for alphabetic languages read in the opposite direction (i.e., from right to left) has received very little attention in empirical research. Accordingly, we investigated the perceptual span for Arabic, which is one of the world's most widely read languages and is read from right to left, using a gaze-contingent window paradigm in which a region of text was displayed normally around each point of fixation, while text outside this region was obscured. Skilled Arabic readers who were bilingual in Arabic and English read Arabic and English sentences while a window of normal text extended symmetrically 0.5° to the left and right of fixation or asymmetrically, by increasing this window to 1.5° or 2.5° to either the left or the right. When English was read, performance across window conditions was superior when windows extended rightward. However, when Arabic was read, performance was superior when windows extended leftward and was essentially the reverse of that observed for English. These findings show for the first time that a leftward asymmetry in the central perceptual span occurs when Arabic is read and, for the first time in over 30 years, provide a new indication that the perceptual span for alphabetic languages is modified by the overall direction of reading