Pupil dilation serves as a continuous measure of listening effort during speech comprehension

Evidence

Pupil size was recorded together with gaze fixations using a sampling rate of 250 Hz. The stimuli were presented via a speaker in sound attenuated room. The lighting in this room was kept constant throughout the experiment to avoid effects of ambient light intensity on the pupil diameter. … To investigate the effort involved in the process of lexical competition with and without semantic context, the pupil dilation data per participant were baseline-corrected to the 200 ms preceding the presentation of the experimental item. — Dijk, Pim van, Physiology, Psychoacoustics and…, 3959

2.4.2 Pupil Dilation To investigate the effort involved in the process of lexical competition with and without semantic context, the pupil dilation data per participant were baseline-corrected to the 200 ms preceding the presentation of the experimental item. The baseline-corrected data were normalized to correct for individual differences in pupil size, according to the equation: For the statistical analysis, the pupil size data, as captured by the event-related pupil dilation (ERPD), were analyzed analogously to the fixation data, as time curves of pupil dilation. — Dijk, Pim van, Physiology, Psychoacoustics and…, 3975

Categorization

• XREF: Links to pupillometry-as-cognitive-load literature (Kahneman); connects to the reader’s interest in effortful listening under degradation.
• corroborated: 2 independent passages support this claim — Dijk, Pim van, Physiology, Psychoacoustics and…, 3959; Dijk, Pim van, Physiology, Psychoacoustics and…, 3975