Effects of Reading Direction on Visuospatial Organization: A Critical Review

Over the past decades, a growing literature on perceptual bias has investigated the factors that determine normal performance in simple visuospatial tasks, such as line bisection and aesthetic preference. Normal right-handed participants may exhibit spatial asymmetries in these tasks with a tendency to bisect to the left of the objective middle in line bisection and a preference for images with the center of interest in their right half in aesthetic preference tasks. These patterns of performance have mostly been attributed to hemispheric imbalance. Other explanations have also been put forth to explain the spatial asymmetries seen in the normal population. Here we review studies that target the role of reading direction on visuospatial tasks. In addition to presenting several of our studies that investigated differences in line bisection and aesthetic preference performances between left-to-right readers (French) and right-to-left readers (Israeli), we present a discussion of the existing literature on reading direction, culture and visuospatial processing. The findings are discussed regarding the interaction between cultural factors, such as reading habits, and biological factors, such as cerebral lateralization, in visual perception

Visual Aesthetic Preference: Effects of Handedness, Sex, and Age-Related Reading/Writing Directional Scanning Experience.

International audienceMost studies of visual aesthetic preference report that right-handers prefer pictorial arrangements possessing left-to-right directionality and/or containing the region of greatest weight or interest on the right side. However, visual aesthetic preference has also been linked to directional scanning depending on the individual's reading/writing habits. The present study aims to assess the respective role of biological factors, related to the functional specialization of the two cerebral hemispheres, indexed by handedness, and cultural factors (age-related reading/writing habits) in visual aesthetic preference. For this purpose, we tested the effects of handedness, sex and age on visual aesthetic preference in 40 children and 40 adults. Results revealed effects of handedness, sex, and age as well as a relationship between directional scanning, reading/writing habits and handedness. The question of a dynamic model of cerebral specialization based on interplay between cerebral plasticity and cultural/environmental factors is raised. Key words: Aesthetic preference, development, vision, hemispheric specialization, handedness, sex, reading/writing habits

Egocentric reference in bidirectional readers as measured by the straight-ahead pointing task.

International audienceThe present study aimed to show that bidirectional reading and language exposure influence the position of egocentric reference (ER), the perceived direction of the body's sagittal axis proposed to act as an anchor for movements in extracorporeal space. Directional factors (e.g., visual scanning bias and reading habits) have been proposed to influence visuospatial performance, such as in line bisection and figure drawing. In past studies, bidirectional readers have been less consistent in demonstrating a bias compared to unidirectional readers. Using a straight-ahead pointing task to assess egocentric reference, we compared 14 unidirectional left-to-right readers (Uni-LR) to three bidirectional reading groups that differed in the reading direction of their native language and/or the level of their second language literacy: 16 low-English literate, native right-to-left, bidirectional readers (Lo-Bi-RL), 13 high-English literate, native right-to-left, bidirectional readers (Hi-Bi-RL), and 15 native left-to-right, bidirectional readers (Bi-LR). Participants were asked to point straight-ahead while blindfolded using either a left-to-right or a right-to-left scanning direction to approach the subjective sagittal midline. Uni-LRs showed left-side spatial bias when scanning left-to-right and right-side bias during right-to-left scanning, Bi-LRs and Lo-Bi-RLs (i.e., intermediate level or less in their second language) demonstrated the opposite pattern, and Hi-Bi-RLs showed left-side spatial bias regardless of scanning direction. Results are discussed in terms of accuracy and spatial bias regarding the interaction between reading direction and spatial cognition based on the level of bidirectional literacy and language exposure

Visual demand and visual field presentation influence natural scene processing

International audienceBACKGROUND: Bottom-up and top-down processes are involved in visual analysis of scenes. Here we examined the influence of top-down visual demand on natural scene processing. METHODS: We measured accuracy and response time in adults performing two stimuli-equivalent tasks. Unfiltered, low or high spatial frequency (SF) natural scenes were presented in central, left, or right visual fields (CVF, LVF, RVF). The tasks differed only by the instructed visual demand. In the detection task, participants had to decide whether a scene was present or not. In the categorization task, they had to decide whether the scene was a city or a forest. RESULTS: Higher accuracy was seen for the LVF in the detection task, but for categorization, greater accuracy was seen for the RVF. The interaction between Task and SF revealed coarse-to-fine processing in the categorization task for both accuracy and reaction time, which nearly disappeared in the detection task. Considering the interaction of Task, VF and SF, a left-hemisphere specialisation (i.e., RVF advantage) was observed for the categorisation of HSF scenes for accuracy alone, whereas a LVF advantage was seen for all SFs in the detection task for both accuracy and reaction time. CONCLUSION: Our results revealed that the nature of top-down visual demand is essential to understanding how visual analysis is achieved in each hemisphere. Moreover, this study examining the effects of visual demand, visual field presentation, and SF content of stimuli through the use of ecological stimuli provides a tool to enrich the clinical examination of visual and neurovisual patients