Dual-stage and dual-deficit? Word recognition processes during text reading across the reading fluency continuum

Abstract

Central questions in the study of visual word recognition and developmental dyslexia are whether early lexical activation precedes and supports decoding (a dual-stage view) or not (dual-route view), and the locus of deficits in dysfluent reading. The dual-route view predicts early word frequency and length interaction, whereas the dual-stage view predicts word frequency effect to precede the interaction effect. These predictions were tested on eye movements data collected from (n = 152) children aged 9–10 among whom reading dysfluency was overrepresented. In line with the dual-stage view, the results revealed an early word frequency effect in first fixation duration followed by robust word length effect in refixation probability and an interaction of word frequency and word length in summed refixation duration. This progression was advanced in fluent reading to be observable already in first fixation duration. Poor reading fluency was mostly explained by inflated first fixation durations, and to stronger word frequency and length effects in summed refixation duration. This pattern of results suggests deficits in early letter encoding and slowness in serial grapheme-phoneme conversion. In contrast to the widely held belief, the holistic orthographic processing of words seemed to be intact.

The Role of Visual Factors in Dyslexia

“…Single source accounts can be contrasted with multifactorial accounts (e.g., Catts & Petscher, 2022;Grainger et al, 2016;Haft et al, 2016;McGrath et al, 2020;Ozernov-Palchik et al, 2016;Pennington, 2006;Pennington et al, 2012;Peters et al, 2019;van Bergen et al, 2014;Vandermosten et al, 2016) where reading ability is assumed to require the interlocked function of many different mechanisms throughout prenatal and postnatal development, and no single cause is necessary or sufficient for dyslexia to occur. Such accounts are consistent with several theories and models suggesting that reading involves a variety of mechanisms (e.g., Castles & Coltheart, 1993;Coltheart et al, 2001;Hautala et al, 2022;Perry et al, 2010;Ziegler et al, 2008), and accordingly there may be many ways in which reading can go wrong. For example, Castles & Coltheart (1993) argue for at least two varieties of developmental dyslexia, characterized by weaknesses in a lexical route (involving retrieval of phonological information from a mental lexicon containing representations of real words) and a sublexical route (involving the use of letter-to-sound rules).…”

“…Finally, unusual eye movements in dyslexia may reflect different processing strategies, including in holistic vs. featural processing. For example, Hautala et al (2022) tracked eye movements during reading and concluded that holistic orthographic processing of words is likely intact in non-fluent readers.…”

“…For example, the connectionist multiple-trace memory model for polysyllabic word reading (Ans et al, 1998;Valdois et al, 2004) posits two procedures that support reading: a global procedure where a visual attentional window extends over a whole word, followed by an analytic procedure where a narrower attentional window moves through parts of a word. Hautala et al (2022) also suggest that readers' visual word recognition involves a two-stage process: holistic lexical processing of a word followed by a more fine-grained analysis involving grapheme-to-phoneme conversion. This bears some resemblance to how global and fine visual information is encoded by single neurons in high-level regions of the ventral visual pathway (Sugase et al, 1999), with global information being present early, converging later with more detailed information (see also Petras et al, 2019).…”