Neural mechanisms for assessing the temporal characteristics of events on a hundreds-of-milliseconds to seconds time scale are fundamental to human perception and performance. On this time scale, research supports at least two distinct mechanisms: an interval-based ('stopwatch') mechanism that records, stores and compares durations and a beat-based ('entrainment') mechanism that assesses the relative timing of events with respect to an internally-generated periodicity. One topic that has received relatively little research attention is the issue of individual differences. This project considers the possibility that individuals engage in beat-based and interval-based timing, but do so to different degrees. The general project aim is to identify and characterize factors mediating engagement of beat-based and interval-based timing mechanisms. Three lines of research will combine a novel sequence-timing paradigm that demonstrates robust individual differences, with a mathematical model that indexes the degree to which performance reflects beat-based judgments. Critical to the sequence-timing paradigm are stimulus sequences that yield opposite perceptions about sequence rate ('speeding up' versus 'slowing down') depending on whether individuals engage in beat-based or interval-based timing, respectively. The first line examines stimulus characteristics mediating beat-based timing. The second line assesses flexibility in timing mode, focusing on attention and task factors. The third line addresses developmental and training factors. A key contribution of the proposed modeling work is that it integrates two contrasting theories of timing within a single framework. Using this framework to clarify the degree to which individuals engage in beat-based timing will improve current limited understanding of individual differences in timing behavior and will help better characterize temporal processing deficits linked to neurological disorders. This project also will contribute to and strengthen the research and educational environment at the JP Scott Center for Neuroscience, Mind and Behavior at Bowling Green State University by providing unique opportunities for interdisciplinary training and collaborative research activities for undergraduate and graduate students.
