A story about statistical learning in a story: Regularities impact eye movements during book reading

A wealth of research attests to the key role of statistical learning in the acquisition and execution of skilled reading. Little is known, however, about how regularities impact the way readers navigate through their linguistic environment. While previous studies have mostly gauged the recognition of single words, oculomotor processes are likely influenced by multiple words at once. With these premises in mind, we performed analyses on the GECO book reading corpus to determine whether repeatedly encountering a given sentence structure improves oculomotor control. In the reading materials we labeled structures on the basis of both low- and high- level properties: respectively word length combinations (e.g., a 2-letter word followed by a 6-letter word followed by a 4-letter word) and syntactic structures (e.g., an article followed by a noun followed by a verb). Our analyses show that repeatedly encountering a structure leads to fewer and shorter fixations, and fewer corrective saccades. Critically, learning curves are steeper for structures that have a higher overall frequency, hence evidencing true statistical learning over and above readers' general tendency to accelerate as they progress through the book. Further, data from Dutch-English bilingual readers suggest that these types of learning occur across languages and at various levels of proficiency. We surmise that the reading system is tuned to statistical regularities pertaining not just to single words but also combinations of words. These regularities impact both linguistic processing and oculomotor control.