Abstract
If perception is the interpretation of sense data, a fundamental question for neuroscience is how we perceive time, because there are no time sensors on the body. A popular view is that timing information is distributed in the dynamics of brain activity and thus can be distorted for each modality independently (Ivry & Schlerf, 2008; Eagleman, 2008; Pariyadath & Eagleman, 2007). Using the visual oddball paradigm, I replicate earlier work showing a visual event's duration can be distorted by a factor of 1.5 (Tse, Intriligator, Rivest & Cavanagh, 2004) but extend the work to show crossmodal interactions with the motor system. When people view stimuli known to produce time distortion, they are reliably slower at responding to the onsets than the offsets, and furthermore they are faster at these onsets compared to the onsets for matched events that do not produce time distortion (r2=0.81). However, the motor responses alone were sufficient to eliminate the duration distortion effect (PSE≈0.923, n.s.). The distortion was unaffected by perceived onsets and offsets as measured by auditory matching. We interpret the results as evidence for the motor system's primacy in timing tasks and suggest the modality-independent view of time perception needs to be reconsidered.
The feedback and advice of Terry Sejnowski and Marta Kutas is gratefully acknowledged.