Improvements in reading accuracy as a result of increased interletter spacing are not specific to children with dyslexia

Abstract

Recently, increased interletter spacing (LS) has been studied as a way to enhance reading fluency. It is suggested that increased LS improves reading performance, especially in poor readers. Theoretically, these findings are well substantiated as a result of diminished crowding effects. Empirically, however, findings on LS are inconclusive. In two experiments, we examined whether effects of increased LS are specific to children with dyslexia and whether increased LS affects word or sentence processing. In the first experiment, 30 children with dyslexia and 30 controls (mean age=9years 11months) read sentences in standard and increased LS conditions. In the second experiment, these sentences were read by an unselected sample of 189 readers (mean age=9years 3months) in either a sentence or word-by-word reading condition. The first experiment showed that increased LS affected children with dyslexia and controls in similar ways. Participants made fewer errors in the increased LS condition than in the standard LS condition. Reading rates were not affected. There were no indications that the effect of LS was related to reading ability, not even for a subgroup of readers. Findings of the second experiment were similar. Increased LS resulted in fewer errors, not faster reading rates. This was found only when complete sentences were presented, not when sentences were read word by word. Three main conclusions can be drawn. First, increased LS appears to affect reading accuracy only. Second, the findings do not support claims that increased LS specifically affects poor readers. And third, the effect of LS seems to occur at the interword level. Theoretical and practical implications of these findings are discussed.

Letter processing in upright bigrams predicts reading fluency variations in children.

“…It also indicates a possible resolution to conflicting evidence in the literature with regard to letter spacing. Some studies have found improved reading speed and accuracy with increased letter spacing (Hakvoort et al, 2017; Zorzi et al, 2012), whereas others have found that reading speed is optimal at the default spacing (Perea et al, 2011; van den Boer & Hakvoort, 2015). We speculate that these discrepancies could reflect differences in the statistics of letter characteristics (e.g., font, spacing, size) as experienced by sampled readers in different studies.…”

“…We therefore wondered whether this effect would also be specific to frequently encountered letter spacings. This is an important question by itself because changes in letter spacing affect reading speed and children with dyslexia have been shown to be particularly impacted by spacing features (Hakvoort et al, 2017; van den Boer & Hakvoort, 2015; Zorzi et al, 2012). In addition, by testing the same participants after ∼10 months, we also asked whether improvements in reading fluency can be predicted from changes in bigram processing.…”

Visual search for upright bigrams predicts reading fluency in children

“…It also indicates a possible resolution to conflicting evidence in the literature with regard to letter spacing. Some studies have found improved reading speed and accuracy with increased letter spacing (Zorzi et al, 2012;Hakvoort et al, 2017), whereas others have found that reading speed is optimal at the default spacing (Perea et al, 2011;van den Boer and Hakvoort, 2015).…”

“…We therefore wondered whether this effect would also be specific to frequently encountered letter spacings. This is an important question by itself because changes in letter spacing affect reading speed (Zorzi et al, 2012;van den Boer and Hakvoort, 2015;Hakvoort et al, 2017). In addition, by testing the same participants after ~10 months, we also asked whether improvements in reading fluency can be predicted from changes in bigram processing.…”

Cognitive Correlates of Reading Fluency in Chinese School-Aged Children

“…In addition, the crowding effect was particularly strong in dyslexic readers (Martelli et al, 2009). It was found that increasing the word and line spacing between English letters promoted reading fluency in dyslexic children (Zorzi et al, 2012) and improved reading accuracy in normal school-age children (Hakvoort et al, 2017). Previous research suggested that the size of the Chinese character visual span, i.e., the maximum number of characters that could be recognized without moving the eyes, was affected by the complexity of the characters and was mediated in large part by visual crowding (Wang et al, 2014).…”