The metrics of regressive saccades during reading in 13 written languages

A well-documented phenomenon in research on eye movement control during reading is the systematic relationship between the landing positions of forward saccades and target word characteristics. However, the behaviour of regressive saccades, which move the eyes in the opposite direction, remains less explored. This study delves into the landing positions of regressive saccades, emphasizing the distinction between intra-word and inter-word regressions, across diverse languages. Using data from the MECO L1 project, which includes eye-tracking data from 589 participants across 13 languages, we scrutinize the precise landing positions of regressions vis-à-vis forward saccades. Our analysis shows a robust effect of launch distance on landing positions for progressive saccades, with undershoots increasing as launch distance grows and overshoots with shorter launch distances. In contrast, regressive inter-word saccades show only minimal variation in landing positions, typically landing near the centre of the target word regardless of launch distance or word length. Intra-word regressions, however, display a pattern similar to progressive saccades, where the landing position is influenced by launch distance, tending to overshoot the optimal viewing position as the launch site moves away from the word's end. This pattern is consistent across all languages. These findings support the notion of cross-linguistic universality in oculomotor control mechanisms during reading, particularly the precision of regressive saccades. They align with the spatial coding hypothesis, suggesting that precise spatial memory of word positions guides regressive saccades.