Situation-specific listening effort as a marker of speech perception success

Correct repetition of speech does not indicate the various effortful processes involved, such as mentally repairing words that were missed, ignoring words because they are already known, or targeting specific words containing key information. Across a series of studies, these abilities were tested using stimuli that gave listeners the opportunity to treat the same speech content with different strategies based on situational needs and cues. Momentary changes in listening effort and sensory gain were revealed by changes in pupil dilation and suppression of microsaccades linked to key stimulus landmarks. Typical-hearing listeners consistently exerted effort at specific times, such as the moment after missing a target word or when hearing repetition of a stimulus previously missed, while also reducing effort during speech that was already heard or irrelevant to the task. However, listeners with cochlear implants instead showed signatures of sustained effort that persisted after stimulus presentation, was not specific to key moments of information, and which did not decrease for irrelevant or redundant speech. These results suggest that listener-driven effort can be situationally dependent, and the ease and quickness of regulating effort is a dimension of success that would not be revealed by measures of word repetition accuracy.