Inter-word and Inter-letter 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 one 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 inter-letter spacing have been mixed with some authors reporting facilitation and others reporting inhibition (van den Boer & Hakvoort, 2015). We present findings from three 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 inter-letter spacing interacts with inter-word spacing, as the required space between words depends on the amount of space used between letters. Inter-word spacing also interacted with word type as the inhibition seen with smaller inter-word spacing was evident with nouns and verbs but not with function words.