Abstract
Pupil dilation as a measure of cognitive effort in listening tasks has been well documented (Kahneman & Beatty 1966; Kuchinsky et al. 2013; Piquado et al. 2010; Wingfield et al. 2015; Winn et al. 2016). However, a direct comparison of the pupillary dynamics while attending to different types of auditory tasks has not been investigated; nor has the nature of pupillary response elicited by processing simple auditory stimuli (tones) versus more complex speech stimuli (words, sentences) been explored. In this thesis, I examine several parameters of changes in young adults’ pupil size, including peak amplitude and rate of increase to peak, elicited while making decisions about auditory stimuli that varied in acoustic or linguistic complexity. Results showed that peak pupil amplitude was the greatest in a lexical decision task, smaller for a sentence decision task, and the smallest in a tone decision task. The sentence decision task resulted in a longer duration to peak compared to tone decision and lexical decision tasks. These results suggest that differences in listening/decision tasks influence the dynamics of the pupillary response, which may suggest differences in processing effort. A pilot study that examines older adults’ pupil size while attending to the same auditory decision tasks is included in this thesis as an indication of future direction this work will take.