What is the role of visual skills in learning to read?

Although the issue of visual skills in relation to word reading has not been central to recent explorations of reading development, all visual word reading involves visual skill. Children constantly face tasks of differentiating visually similar letters or words. For example, distinguishing “b” from “d,” “a” from “e,” or “book” from “boot” all require visual differentiation. Children’s orthographic knowledge and letter knowledge are causal factors in subsequent reading development in English (e.g., Badian, 1994; Lonigan et al., 2000). At a pure visual skill level, some researchers (e.g., Franceschini et al., 2012) suggest that core visual processing skills such as visual spatial attention in preschoolers could be a causal factor in subsequent reading acquisition. In addition, some alphabetic readers with dyslexiamay have visual processing deficits (e.g., Valdois et al., 2004; Van der Leij et al., 2013). Following this hypothesis, Franceschini et al. (2013) showed that action video games that strengthened children’s visual attention also improved their reading speed in Italian without sacrificing reading accuracy, similar to previous interventional research training facilitating visuospatial attention skills in Italian children with dyslexia (Facoetti et al., 2003). However, orthographic depth mediates the role of visual attention in reading (Bavelier et al., 2013; Richlan, 2014). English is a more opaque orthography than Italian, and Chinese is even more opaque than English. Both eye movement and neuroimaging studies have demonstrated that reading Chinese affects visual processing differently than does reading alphabetic orthographies (e.g., Inhoff and Liu, 1998; Perfetti et al., 2010; Szwed et al., 2014). Inhoff and Liu (1998) found that Chinese readers used comparatively smaller visual perceptual spans than English readers. Szwed et al. (2014) found that readers of Chinese showed strong activations in intermediate visual areas of the occipital cortex; these were absent in French readers. Researchers have attributed these characteristics to perceptual learning resulting from learning to read Chinese characters (Rayner, 1998; Perfetti et al., 2010; Szwed et al., 2014). Indeed, the role of visual skills for early reading development may be stronger for reading Chinese than reading English. Pure visual skills are sometimes relatively strong correlates of Chinese children’s reading (e.g., Huang and Hanley, 1994, 1995; Ho and Bryant, 1997; Siok and Fletcher, 2001; Mcbride-Chang et al., 2005; Luo et al., 2013). Such visual tasks likely tap at least three visual skills thatmay be required for Chinese character reading. First, a focus on visual form constancy (e.g., is this square the same size as the one embedded in other designs on the previous page?) likely has some analogies with the fact that radicals within Chinese might appear as larger or smaller or even reversed in appearance across characters. Second, a focus on visual spatial skills, i.e., identifying the same form when it is in a different direction or placed differently, might be useful when Chinese character identification requires children to reduce a compact character into component radicals. Third, visual memory may be useful in learning to read Chinese in at least two ways, namely, making associations between characters and sounds, many of which are arbitrary, sometimes referred to as visual verbal paired associate learning, and helping children to build a mental memory of how different radical parts are located within a character. What is the evidence that learning to read Chinese trains one’s visual skills? A cross-cultural study (McBride-Chang et al., 2011b) found that Chinese and Korean kindergartners performed significantly better than Israeli and Spanish children on a task of visual spatial relationships, the only visual task tested across all four cultures. Korean kindergartners tend to learn to read Korean syllables holistically initially, similar to how Chinese characters are taught. A superior performance on visual skills was also found by Demetriou et al. (2005) for older Chinese as compared to Greek children. In addition, Huang and Hanley (1994) found that both Taiwanese and Hong Kong children showed a clear advantage on the visual form discrimination task as compared to their British peers. Interestingly, the Chinese written system has two versions, the simplified and the traditional. The simplified script, which has fewer visual features to distinguish one character from another, may make more visual demands than does the traditional version. In one study of those learning to read traditional (in Hong Kong) as compared to simplified (in Mainland China) script, those learning the simplified script outperformed those learning the traditional one on three visual tasks, namely visual discrimination, visual spatial relationships and visual closure tasks (Mcbride-Chang et al., 2005), even across time. Peng et al. (2010) found that electrophysiological response potentials (ERPs) in the brains of those expert readers who saw characters with one stroke either added or subtracted in a few milliseconds showed the same basic pattern: