Note on the Dual-Task Paradigm and its Use to Measure Listening Effort

People regularly communicate in complex environments, requiring them to flexibly shift their attention across multiple sources of sensory information. Increasing recruitment of the executive functions that support successful speech comprehension in these multitasking settings is thought to contribute to the sense of effort that listeners often experience. One common research method employed to quantify listening effort is the dual-task paradigm in which individuals recognize speech and concurrently perform a secondary (often visual) task. Effort is operationalized as performance decrements on the secondary task as speech processing demands increase. However, recent reviews have noted critical inconsistencies in the results of dual-task experiments, likely in part due to how and when the two tasks place demands on a common set of mental resources and how flexibly individuals can allocate their attention to them. We propose that in order to move forward to address this gap, we need to first look backward: better integrating theoretical models of resource capacity and allocation as well as of task-switching that have been historically developed in domains outside of hearing research (viz., cognitive psychology and neuroscience). With this context in mind, we describe how dual-task experiments could be designed and interpreted such that they provide better and more robust insights into the mechanisms that contribute to effortful listening.