Saturday, April 19, 2025
4/19/2025
Mechanisms of auditory selective attention for speech and non-speech stimuli - PROJECT SUMMARY/ABSTRACT In ecological listening environments, individuals must direct attention toward a specific source (e.g., the voice of a friend) while ignoring simultaneous background noise (e.g., other patrons in a café). Moreover, listeners must direct attention toward specific dimensions within an auditory source (e.g., frequencies useful for distinguishing between different speech sounds). A widely held but untested assumption is that these source-based and dimension-based forms of auditory selective attention are supported by common mechanisms. Human studies have historically focused on source-based attention using speech stimuli, while nonhuman animal studies have primarily investigated dimension-based attention with non-speech stimuli; there is thus an empirical gap between these literatures, making it unclear how well the animal studies can model human behavior. More generally, the mechanisms that support auditory selective attention remain underspecified. For instance, extant research suggests that selective attention involves enhancing representations of key information, but it is unclear whether selective attention also involves actively suppressing irrelevant information. Thus, the goal of the proposed project is to clarify the cognitive and neural mechanisms that support auditory selective attention. The first aim is to determine whether auditory selective attention involves suppression of irrelevant information. The key scientific premise is to use training as a tool for triangulating mechanism. That is, if selective attention involves suppression of irrelevant auditory dimensions, then training that improves a listener’s ability to suppress irrelevant auditory information should be associated with concomitant gains in auditory selective attention. Listeners will receive eight days of auditory training that either will require them to perform increasingly fine- grained processing in a target frequency band (promoting enriched representations of target dimensions) or will place increasing demands on the extent to which they must suppress irrelevant auditory dimensions (e.g., a non- target frequency band). Of interest is whether training is associated with improved auditory selective attention, as measured through classic behavioral and electrophysiological indices of attention. The second aim is to determine whether different forms of auditory selective attention (e.g., source-based and dimension-based) are supported by common mechanisms. If they are, then training that leads to improvements in one type of auditory selective attention (e.g., dimension-based) should generalize to another (e.g., source-based). Listeners will complete tests of generalization before, midway through, and after the training regimen. Of interest is whether an improved ability to attend to target auditory dimensions is associated with an improved ability to direct attention toward a specific source. Tests will also assess whether training with non-speech stimuli generalizes to speech. The results will provide insight into the extent to which different forms of auditory selective attention are supported by common mechanisms. Overall, the proposed work will clarify the mechanisms supporting auditory selective attention and provide a vital missing link between the nonhuman animal and human literatures.
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