The pupil response reveals increased listening effort when it is difficult to focus attention

Abstract

Recent studies have shown that prior knowledge about where, when, and who is going to talk improves speech intelligibility. How related attentional processes affect cognitive processing load has not been investigated yet. In the current study, three experiments investigated how the pupil dilation response is affected by prior knowledge of target speech location, target speech onset, and who is going to talk. A total of 56 young adults with normal hearing participated. They had to reproduce a target sentence presented to one ear while ignoring a distracting sentence simultaneously presented to the other ear. The two sentences were independently masked by fluctuating noise. Target location (left or right ear), speech onset, and talker variability were manipulated in separate experiments by keeping these features either fixed during an entire block or randomized over trials. Pupil responses were recorded during listening and performance was scored after recall. The results showed an improvement in performance when the location of the target speech was fixed instead of randomized. Additionally, location uncertainty increased the pupil dilation response, which suggests that prior knowledge of location reduces cognitive load. Interestingly, the observed pupil responses for each condition were consistent with subjective reports of listening effort. We conclude that communicating in a dynamic environment like a cocktail party (where participants in competing conversations move unpredictably) requires substantial listening effort because of the demands placed on attentional processes.

Pupillometry as an objective measure of sustained attention in young and older listeners

“…Pupil dilation has long been used as a measure of effort (Beatty, 1982;Bradshaw, 1968;Cabestrero et al, 2009;Granholm and Steinhauer, 2004;Hjortkjaer et al, 2018;Wel and Steenbergen, 2018) and is presently attracting considerable interest in the auditory modality because of evidence that pupil dilation can be used as an objective means with which to evaluate challenges to listening (McGarrigle et al, 2014;Peelle, 2018;Pichora-Fuller et al, 2016). The bulk of existing work has used pupillometry to evaluate listening effort associated with degraded speech (Koelewijn et al, 2012(Koelewijn et al, , 2014(Koelewijn et al, , 2015Kuchinsky et al, 2014;Naylor et al, 2018;Ohlenforst et al, 2017;Wang et al, 2017;Wendt et al, 2016Wendt et al, , 2017Winn et al, 2015Winn et al, , 2018Zekveld et al, 2010Zekveld et al, , 2011Zekveld et al, , 2018. As a result, these tasks inherently challenged both the ability to cope with energetic masking and the ability to sustain attention over time.…”

Disentangling listening effort and memory load beyond behavioural evidence: Pupillary response to listening effort during a concurrent memory task

“…Its popularity can be 19 attributed to its sensitivity to a wide range of cognitive tasks and processing that relate 20 to the concept of listening effort [3,14,15]. Past studies have shown that pupil size 21 varies with different speech intelligibility, hearing impairment, lexical manipulation, 22 masker type, spectral resolution, memory load and divided/focused attention [4,[16][17][18][19][20][21][22][23]. 23Typically, when task demands increase, for instance, with lower SNR, degraded spectral 24 resolution or more digits to remember, pupil size increases.…”

Speech masking speech in everyday communication: The role of inhibitory control and working memory capacity

“…In combination with the changes in auditory perception, age -related cognitive decline influences processing of auditory information and speech perception (Humes et al, 2012). Focusing on, switching between, and ignoring auditory stimuli increases cognitive load, and adding a hearing impairment increases further load on the cognitive system (Koelewijn et al, 2015). The person struggling to hear the message from a conversation might experience frustration when trying to sift between the different auditory stimuli taxing the cognitive resources (Rudner, Rönnberg & Lunner, 2011).…”

“…Listening effort has previously been investigated using various methods (see for example Koelewijn et al, 2015;Larsby et al, 2005;Zekveld et al, 2014)., e.g. pupillometry, which is used to quantify cognitive processing load by measuring pupil dilation in relation to task demands and cognitive load (Koelewijn et al, 2015;Zekveld et al, 2014).…”

“…pupillometry, which is used to quantify cognitive processing load by measuring pupil dilation in relation to task demands and cognitive load (Koelewijn et al, 2015;Zekveld et al, 2014).…”