Perceiving filled vs. empty time intervals: A comparison of adjustment and magnitude estimation methods
A time interval between the onset and the offset of a continuous sound (filled interval) is often perceived to be longer than a time interval between two successive brief sounds (empty interval) of the same physical duration. The present study examined the occurrence of such phenomenon, sometimes called the filled duration illusion, for time intervals of 40-520 ms with the method of adjustment and the method of magnitude estimation. When the method of adjustment was used, the filled duration illusion appeared clearly for a few participants, while it did not appear for the majority of participants. With magnitude estimation, the filled duration illusion was more likely to occur. The amounts of the illusion did not correlate between the two methods, and it was suggested that even for the same participant, the perception of the empty and the filled intervals can be influenced by the experimental methods.