Abstract
Attention distorts perceived time. This attentional modulation of perceived time can occur as the result of modulation of the encoded duration itself, changes to the onset of the encoded duration, or both. In the present study, we investigated the role of attention in sub-second duration encoding, and focused especially on the effect of changes to the onset time. The duration perception of ten participants was tested with a behavioral oscillation paradigm, in which performance in a detection task fluctuates as a function of cue-to-target intervals. It has been suggested that the behavioral oscillation reflected periodic attentional modulations in perception. In the training phase, the participants learned two standard durations: 325 ms and 775 ms. In the test phase, a brief attentional cue was presented followed by a target. The participants were instructed to answer whether the target duration was closer to which of the two standard durations. The attentional cue and the target were presented in the same visual field (valid condition) or in different visual fields (invalid condition). The cue-to-target intervals were varied by 25 ms, between 250 ms and 1050 ms. Seven target durations were evenly spread between 325 ms and 775 ms. The bisection point (the duration giving 50% "long" responses) was calculated for each cue-to-target interval. The bisection point in the valid condition fluctuated at around theta rhythm as a function of cue-to-target interval. Fitting to the single-frequency sine function and permutation testing confirmed statistically significant behavioral oscillation at the bisection point. The results indicate that attentional modulation of perceived time is at least partially due to onset-induced change to the encoded duration. The behavioral oscillations we observed in this study also suggest that periodic attentional modulation is involved in relatively complicated perceptual tasks such as duration perception.
Meeting abstract presented at VSS 2016