Recent studies have investigated how effort and difficulty during conversational interactions can be inferred from pupillary responses. Yet, the primary intervention in these studies is background noise, the presence of which inherently modulates the size of the pupil. This study investigates this concern by comparing pupillary responses between conditions where acoustic (background noise) and non-acoustic (second language) factors were varied to alter expected conversational difficulty. Data was collected from 20 pairs of university-aged, normal-hearing, native-Ukrainian talkers who held conversations in their first language (Ukrainian) and a second language (English) both in the presence and absence of background noise. Pupil responses were measured around the starts and ends of conversational turns and assessed for differences in size and temporal dynamics based on language proficiency and background noise. Results will compare how these aspects of the pupil response vary based on the source of conversational difficulty. The implications of these findings will be discussed, including the potential for extending the pupil response from a general marker of effort/attention to one that can differentiate between distinct higher-level processes. The impact of these findings for understanding the effects of other sources of difficulty, such as hearing loss, will also be considered.
Masters et al. (Wed,) studied this question.