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Time-shrinking: the process of unilateral temporal assimilation.
Yoshitaka Nakajima1, Gert ten Hoopen, Takayuki Sasaki
1Department of Acoustic Design, Kyushu Institute of Design, Fukuoka, Japan. nakajima@design.kyushu-u.ac.jp
Perception
|November 25, 2004
Summary
Shorter preceding auditory time intervals cause underestimation of subsequent intervals, an effect termed time-shrinking (TS). This illusion occurs when the second interval is longer than the first, with the difference in duration being key.
Area of Science:
- Psychology
- Neuroscience
- Auditory Perception
Background:
- Previous research identified the time-shrinking (TS) illusion in auditory time perception.
- TS involves underestimation of empty time intervals preceded by shorter intervals.
Purpose of the Study:
- To investigate the conditions and characteristics of the time-shrinking illusion.
- To determine the relationship between preceding (t1) and standard (t2) interval durations in TS.
- To model the underlying cognitive mechanisms of TS.
Main Methods:
- Four experiments were conducted using auditory stimuli.
- Participants perceived pairs of empty time intervals (t1 followed by t2).
- The duration of t1 and t2 were systematically varied to observe effects on perception.
Main Results:
- The time-shrinking illusion was clearly observed when t1 ≤ 200 ms and t1 ≤ t2.
- The absolute difference between t1 and t2 was critical for the illusion's occurrence.
- Underestimation of t2 increased with t2 up to t1 + 65 ms, plateaued between t1 + 65 ms and t1 + 95 ms, and vanished when t2 exceeded t1 + 95 ms.
Conclusions:
- The time-shrinking illusion is dependent on the temporal difference between successive auditory intervals.
- A proposed model suggests TS arises from reduced mental processing of the second interval, leading to assimilation of t2 to t1.
- This assimilation explains the underestimation of auditory durations under specific temporal conditions.