[Filled-duration illusion as a function of visual stimulus tempo].

The filled-duration illusion (FDI) was studied by the method of reproduction for longer durations and by that of categorical judgement for shorter durations. The stimulus materials were simultaneously presented dots(LEDs), or successively presented (spatially different) dots, whose duration represented subintervals of a filled duration. Under the successively presented condition, the filled durations shorter than about 600 ms were underestimated (the opposite FDI), whereas the longer filled durations were overestimated, as compared with empty durations. The present results suggest that the major determinant of FDI isn't always an encoding process of subintervals. Rather, it is reasonable to take a view that the determinant is the "personal tempo" as pointed out in the sensory-tonic field theory.