Parafoveal processing and transposed‐letter effects in dyslexic reading

Abstract

During parafoveal processing, skilled readers encode letter identity independently of letter position (Johnson et al., 2007). In the current experiment, we examined orthographic parafoveal processing in readers with dyslexia. Specifically, the eye movements of skilled readers and adult readers with dyslexia were recorded during a boundary paradigm experiment (Rayner, 1975). Parafoveal previews were either identical to the target word (e.g., nearly), a transposed‐letter preview (e.g., enarly), or a substituted‐letter preview (e.g., acarly). Dyslexic and non‐dyslexic readers demonstrated orthographic parafoveal preview benefits during silent sentence reading and both reading groups encoded letter identity and letter position information parafoveally. However, dyslexic adults showed, that very early in lexical processing, during parafoveal preview, the positional information of a word's initial letters were encoded less flexibly compared to during skilled adult reading. We suggest that dyslexic readers are less able to benefit from correct letter identity information (i.e., in the letter transposition previews) due to the lack of direct mapping of orthography to phonology. The current findings demonstrate that dyslexic readers show consistent and dyslexic‐specific reading difficulties in foveal and parafoveal processing during silent sentence reading.

Macular Anatomy Differs in Dyslexic Subjects

“…In fact, parafoveal recognition of embedded letters and words has been proven to be worse in dyslexic subjects than in normal controls [ 34 , 35 , 36 ]. Furthermore, reduced and delayed parafoveal preview benefits have been associated with dyslexia [ 37 , 38 , 39 , 40 ].…”

Bilingual parafoveal processing: Children and adults preprocess orthographic information of the upcoming word during sentence reading in their first and second language.

“…It is well-established that readers are able to process information about upcoming words in a sentence, that is, in the parafoveal field of vision, before their eyes move to fixate on them directly (reviews in Andrews & Veldre, 2019; Hyönä, 2011; Schotter et al, 2012; Vasilev & Angele, 2017). Eye movement studies have shown that skilled adult readers routinely process the orthography of upcoming words (Balota et al, 1985; Binder et al, 1999; Briihl & Inhoff, 1995; Inhoff, 1987, 1989a, 1989b, 1990; Inhoff & Tousman, 1990; Johnson & Dunne, 2012; Johnson et al, 2007; Kirkby et al, 2022; McConkie & Zola, 1979; Milledge et al, 2021; Milledge, Liversedge, & Blythe, 2022; Pagán et al, 2016; Rayner, 1975b; Rayner, McConkie, & Zola, 1980; Staroverova et al, 2023; Tiffin-Richards & Schroeder, 2015a; White et al, 2008; Williams et al, 2006), the phonology of upcoming words (Ashby & Rayner, 2004; Ashby et al, 2006; Chace et al, 2005; Henderson et al, 1995; Milledge, Liversedge, & Blythe, 2022; Pan et al, 2016; Pollatsek et al, 1992, 2000; Tiffin-Richards & Schroeder, 2015a; Vasilev et al, 2019), as well as the semantics of words visible in the parafovea (for discussions see Hohenstein & Kliegl, 2014; Rayner et al, 1986, 2014; Schotter et al, 2012, 2023; Veldre & Andrews, 2016; Yan et al, 2009). Although the extent of semantic processing in the parafovea is still debated, there is a consensus based on consistent replications that the integration of orthographic and phonological codes across fixations is an important aspect of skilled reading (Cutter et al, 2015; Pollatsek et al, 1992; Rayner et al, 1980; Schotter et al, 2012; Vasilev et al, 2019).…”

“…It is wellestablished that readers are able to process information about upcoming words in a sentence, that is, in the parafoveal field of vision, before their eyes move to fixate on them directly (reviews in Andrews & Veldre, 2019;Hyönä, 2011;Schotter et al, 2012;Vasilev & Angele, 2017). Eye movement studies have shown that skilled adult readers routinely process the orthography of upcoming words (Balota et al, 1985;Binder et al, 1999;Briihl & Inhoff, 1995;Inhoff, 1987Inhoff, , 1989aInhoff, , 1989bInhoff, , 1990Inhoff & Tousman, 1990;Johnson & Dunne, 2012;Johnson et al, 2007;Kirkby et al, 2022;McConkie & Zola, 1979;Milledge et al, 2021;Pagán et al, 2016;Rayner, 1975b;Rayner, McConkie, & Zola, 1980;Staroverova et al, 2023;Tiffin-Richards & Schroeder, 2015a;White et al, 2008;Williams et al, 2006), the phonology of upcoming words (Ashby & Rayner, 2004;Ashby et al, 2006;Chace et al, 2005;Henderson et al, 1995;Pan et al, 2016;Pollatsek et al, 1992Pollatsek et al, , 2000Tiffin-Richards & Schroeder, 2015a;Vasilev et al, 2019), as well as the semantics of words visible in the parafovea (for discussions see Hohenstein & Kliegl, 2014;Rayner et al, 1986Rayner et al, , 2014Sch...…”

Dyslexia: Causes and Concomitant Impairments

“…It has also been assumed that dyslexia may be due to an unusual masking of letters by flanking letters (crowding effect) [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 ]. In this case, letters to the left and to the right of a letter decrease its recognition.…”

“…Since the German ophthalmologist Oswald Berkhan [ 1 ] first described the symptoms of dyslexia in 1881 and Rudolf Berlin introduced the term ”dyslexia“ [ 2 ], numerous theories have been proposed about its causes and treatments, [ 3 , 4 ] (for review). The magnocellular theory of dyslexia [ 5 , 6 , 7 , 8 , 9 ], the theory of unusual foveal and parafoveal processing of letters including an unusual crowding effect [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 ], and the temporal summation theory [ 20 , 21 , 22 , 23 ] regard developmental dyslexia (DD) as a visual perceptual disorder. Other theories assume that DD results from an impaired ability to process auditory stimuli [ 24 , 25 , 26 , 27 ] or is caused by impaired control of reading eye movements [ 6 , 7 , 8 , 9 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 ].…”