Interword and interletter spacing effects during reading revisited: Interactions with word and font characteristics.

Abstract

Despite the large number of eye movement studies conducted over the past 30+ years, relatively few have examined the influence that font characteristics have on reading. However, there has been renewed interest in 1 particular font characteristic, letter spacing, which has both theoretical (visual word recognition) and applied (font design) importance. Recently published results that letter spacing has a bigger impact on the reading performance of dyslexic children have perhaps garnered the most attention (Zorzi et al., 2012). Unfortunately, the effects of increased interletter spacing have been mixed with some authors reporting facilitation and others reporting inhibition (van den Boer & Hakvoort, 2015). The authors present findings from 3 experiments designed to resolve the seemingly inconsistent letter-spacing effects and provide clarity to researchers and font designers and researchers. The results indicate that the direction of spacing effects depend on the size of the default spacing chosen by font developers. Experiment 3 found that interletter spacing interacts with interword spacing, as the required space between words depends on the amount of space used between letters. Interword spacing also interacted with word type as the inhibition seen with smaller interword spacing was evident with nouns and verbs but not with function words.

Wider Letter-Spacing Facilitates Word Processing but Impairs Reading Rates of Fast Readers

“…In summary, in line with previous eye-tracking experiments on paragraph reading in English (Slattery et al, 2016) and Spanish (Perea et al, 2016) we observed in a sample of young German readers without a history of reading impairments that wider character spacing produced robust effects of shorter fixation durations that did, however, not translate into reading rate gains. On the contrary, reading rates were slowed down, an effect that was stronger for faster readers and appears attributable to increased numbers of fixations under conditions of wider letter spacing.…”

“…Also, the shorter duration of fixations quite obviously reflects that less information can enter through foveal vision if letters are expanded over a larger part of the visual field in the wider letter spacing condition. This, as a consequence, also generated the need for additional fixations, leading to the observed effect of slower reading rates despite shorter fixation durations, which replicates previous reports for non-impaired readers of Spanish (Perea and Gomez, 2012b;Perea et al, 2016), Hungarian (Weiss et al, 2016), and English (Slattery et al, 2016;Li et al, 2019). An important novel result of the current study is that the strength of the letter spacing effect is mediated by inter-individual differences in reading proficiency: whereas faster readers can suffer substantially from wider letter spacing (i.e., up to 20 to 30 words per minute), slower readers show no or comparably weak effects ( Figure 4B).…”

“…In summary, there is by now a growing body of evidence that wider inter-letter spacing affects reading performance and word recognition not only in dyslexic readers but also in non-impaired readers. For a more comprehensive description of additional studies, which also includes an extensive investigation of text-specific parameters (such as font characteristics) that mediate letter-spacing effects, we refer the reader to Slattery et al (2016).…”

Are two spaces better than one? The effect of spacing following periods and commas during reading

“…Many other fonts used by word processers today utilize proportional fonts (i.e., the computer adjusts for the unique width of each character). Slattery, Yates, and Angele (2016) recently found that interword spacing effects differed depending on whether a fixed width font on a proportional width font was used. Thus, it is possible that the effects of punctuation spacing seen in the current experiment may differ when presented in other font conditions (or other writing systems).…”

The Influence of Typography on Algorithms that Predict the Speed and Comfort of Reading

“…By contrast, Verdana showed comparatively little change with letter spacing. The effects of interword and interletter spacing on reading are known to interact with font characteristics [12].…”