How does reading direction modulate perceptual asymmetry effects?

ABSTRACT

Left-side bias effects refer to a bias towards the left side of the stimulus/space in perceptual/visuospatial judgments, and are argued to reflect dominance of right hemisphere processing. It remains unclear whether reading direction can also account for the bias effect. Previous studies comparing readers of languages read from left to right with those read from right to left (e.g., French vs. Hebrew) have obtained inconsistent results. As a language that can be read from left to right or from right to left, Chinese provides a unique opportunity for a within-culture examination of reading direction effects. Chinese participants performed a perceptual judgment task (with both face and Chinese character stimuli; Experiment 1) and two visuospatial attention tasks (the greyscales and line bisection tasks; Experiment 2) once before and once after a reading task, in which they read Chinese passages either from left to right or from right to left for about 20 min. After reading from right to left, participants showed significantly reduced left-side bias in Chinese character perceptual judgments but not in the other three tasks. This effect suggests that the role of reading direction on different forms of left-side bias may differ, and its modulation may be stimulus-specific.

KEYWORDS:

• Left-side bias
• Reading direction
• Perceptual asymmetry
• Pseudoneglect

Acknowledgements

We thank the editor and two anonymous reviewers for helpful comments and suggestions.

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes

1. In a separate analysis of Experiment 1 (perceptual judgment task), we investigated possible effects of block order (i.e., the order of face/character block) and session (by separating each block into first- and second-half sessions). These two additional factors were added in the original mixed ANOVA in addition to the effects of interest (i.e., group, stimulus type, and time). Neither factor showed any significant interaction with the effects of interest [Group × Stimulus Type × Time × Block Order interaction: F(1, 60) = 0.00, ns; Group × Stimulus Type × Time × Session interaction: F(1, 60) = 0.566, ns; Group × Stimulus Type × Time × Block Order × Session interaction: F(1, 60) = 0.119, ns], indicating the absence of block order and session effects.

2. In a separate analysis, we investigated possible effects of hand of response, block order, and session (by separating each block into first- and second-half sessions) in Experiment 2 (visuospatial attention tasks). None of the above factors showed any significant interaction with the effects of interest (i.e., the Group × Time interaction) in either the GS task [Group × Time × Hand of Response interaction: F(1, 56) = 0.181, ns; Group × Time × Block Order interaction: F(1, 56) = 0.43, ns; Group × Time × Session interaction: F(1, 56) = 1.093, ns; Group × Time × Hand of Response × Block Order × Session interaction: F(1, 56) = 0.01, ns], or the LB task [Group × Time × Hand of Response interaction: F(1, 56) = 0.909, ns; Group × Time × Block Order interaction: F(1, 56) = 1.871, ns; Group × Time × Session interaction: F(1, 56) = 0.058, ns; Group × Time × Hand of Response × Block Order × Session interaction: F(1, 56) = 2.448, ns].

Additional information

Funding

This work was supported by the Research Grant Council of Hong Kong [project number HKU 745210H], [project number HKU 758412H] awarded to Janet H. Hsiao.