This project will investigate the role of the motor system in how people perceive time. The perception of time is fundamental to our conscious experience and critical to virtually all of our activities. However, despite being a focus of research in experimental psychology since the 19th century, time perception is still incompletely understood. Previous work has suggested that the brain controls the timing of our actions and the motor system simply produces an output in response to these timed brain commands. That is, the brain decides when to move and the motor system produces the movement. However, recent research has shown that the motor system may have a much more critical role in timing and may be fundamentally necessary for the perception of time. The investigators will test this idea by having human participants move a robotic arm that can be perturbed by the experimenters. The investigators will explore whether changing the features of the robotic arm movement also alters the subject's perception of time and whether this paradigm can be used to improve the perception of time. The research program combines aspects of the decision-making and motor planning literatures and will provide novel training for graduate and undergraduate students in the two research areas. Finally, understanding timing and movements is critical to the development of brain-machine interfaces and neural prosthetics and may help support interventions in motor rehabilitation and motor disorders.
In most psychological research on time perception in humans, subjects must typically make a choice between two alternatives by pressing a button. This stands in contrast to most animal research, where animals must move to a response location. The investigators intend to bridge the gap between these two literatures with the proposed paradigm. To do this, subjects will be required to move a robotic arm to different locations, depending on their decision about an elapsed interval of time. A series of studies will test the effects of 1) adding resistance to the arm while subjects actively time an interval, 2) actively moving vs. planning a movement while timing an interval, and 3) the impact of moving while judging other, time-critical stimuli (e.g., pitch). In all studies, the investigators will use movement kinematics and dynamics to predict the choices subjects will make and will apply drift-diffusion modeling simulations to elucidate where and how movement parameters impact the perception of time.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
