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.