Spatial release of the cognitive effort of understanding speech in multi-talker environments

Abstract

Ervin Hafter was prescient in recognizing the need for taking into account top-down cognitive processing for understanding the interaction between auditory perception and cognition. His insight, that signal processing such as noise reduction may modify cognitive demands without changing auditory performance, led to a seminal study in collaboration with the Starkey Hearing Research Center which showed that hearing aid technology can reduce the cognitive effort of understanding noisy speech. Inspired by Erv’s insight, we are studying if increasing the spatial separation between competing talkers reduces the cognitive effort needed to listen in multi-talker environments. Following the lead of Erv’s seminal study, performance on a simultaneous secondary task, in our case visual tracking, is a measure of the cognitive effort consumed by the primary task of understanding target speech. Our results show that spatial separation can reduce cognitive effort even when it does not give further improvement in speech intelligibility over existing segregation cues. These results suggest that a measure of cognitive effort is useful for assessing the benefit of hearing technology that improves spatial segregation. This is an important finding because the measure addresses benefit along a dimension that is not captured in standard assessment of speech reception performance.