The time course of recognition of reduced disyllabic Japanese words: Evidence from pupillometry with a Go-NoGo task

While much attention has been paid to the importance of reduction in spoken word recognition, fewer studies have investigated the effect of reduction over time. Thirty-eight participants’ pupillary responses were measured during the perception of Japanese disyllabic words as they performed a Go-NoGo task. We used 226 lexical items, each of which contained both reduced and citation forms of the words. All stimuli consisted of a word-medial nasal or voiced stop. Results demonstrate that the overall amount of cognitive effort required to process reduced forms was higher than that of canonical forms. That is, greater pupil dilation was observed for reduced forms than for citation forms. This result is in line with previous research (e.g., Tucker, 2011). Specifically, pupil dilation was greater with reduced forms in the time window of 436 ms to 2000 ms after the onset of stimuli. Our results also indicate that the pattern of pupil dilation over time with reduced forms differs from citation forms, indicating that reduced forms show a later onset and offset of peak dilation and more gradual constriction of pupil compared to citation forms.