Healthy aging in a social world: Investigating the impacts of cognitive and sensory decline on success in group conversation

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One of the key problems in hearing sciences and human communication is understanding how listeners can attend to one of several simultaneous speakers, e.g. in a crowded restaurant. In such environments, selective attention allows a listener to focus on one talker of interest while filtering out competing talkers and noise. However, in multitalker situations the complexity is even greater because, as the flow of conversation swings between talkers, attention must be distributed among multiple concurrent speakers. Older adults have more difficulty understanding speech in everyday conversational settings than their younger counterparts, which impacts how much they can take part in the conversation and affects their quality of life. These age-related difficulties may be attributed to changes in cognitive processes, sensory processes, or a combination of both. As it can be devastating if the ability to converse easily with others breaks down, this research investigates the basis of age-related difficulties. Specifically, this study examines conversation processing in multitalker environments in adults varying in hearing impairment and age, and links these differences to both cognitive and sensory-processing skills.Experiment 1 will explore how the difficulty of following conversation changes with age, assessing the costs of switching auditory attention during conversational turn-taking in different age groups. Participants will passively listen to pairs of utterances that are either both produced by one speaker, or that switch between two speakers. Target utterances will be presented concurrently with maskers through an array of loudspeakers, and comprehension levels (assessed through multiple choice questions) will be compared between switch and non-switch trials. Subjects will also complete a battery of cognitive tests and tests of auditory function, and the effect of switching talkers will be compared between age groups, and linked to these measures.Experiment 2 will directly manipulate sensory and cognitive processing in younger adults in an attempt to simulate the effects of aging, exploring the extent to which degraded peripheral representations, and cognitive load, affects the ability of listeners to switch attention in multitalker conversations. Comparing the behaviour of these younger adults, and the older adults in experiment 1, will help shed light on whether the difficulty is principally in identifying speech sounds and words in the competing messages, or in tuning attention to the appropriate voice.Finally, experiment 3 will move towards an examination of real interaction, using measures of linguistic comprehension, movement, and gaze during talker switches to better understand conversation processing in complex real-life environments. While the detail of this stage of work will be informed by the prior experiments, possibilities for further study include the value of priming attention towards a new speaker, and the impact of different hearing device modes.While this project will begin by making use of established paradigms, it will then move towards building new interpersonal paradigms to address conversation in an ecologically valid manner. This research will therefore contribute to a more complete picture of the difficulties that older adults experience when listening to conversation in real multitalker environments, and could lead to new ways of supporting the cognitive and sensory components of aging in tandem.