| Listen! | Listen! |
|---|---|
| sampling frequency = 8000 Hz 16 bit MONO Windows PCM | sampling frequency = 8000 Hz 8 bit MONO mu-Law Wave |
The duration of a short time interval can be substatially underestimated when it is immediately preceded by a physically shorter time interval. This illusion is named "time-shrinking" (Nakajima et al, 1991), and it had been interpreted as assimilation between two neighboring intervals (Nakajima et al, 1992). A number of research on time-shrinking had been performed (e.g. ten Hoopen et al, 1993; ten Hoopen et al, 1995).
Suetomi and Nakajima (1997) found that time-shrinking, i.e., the underestimation of the last duration, can take place also when three, instead of two, empty time intervals neighbor each other. The influence of the second time interval was dominant. We had to grasp the relationship between the three neighboring time interval as a whole in order to understand whether time-shrinking occurs or not. We show the applicability of Gestalt principles to time shrinking.
The illusion of time shrinking takes place not only in the three-marker (2 intervals) condition but also in the four-marker (3 intervals) condition.
It is easier for the listener to pick up the last time interval from 4 tone pattern. In this demonstration, the patterns are presented in the order shown as in Table 1.
| No. | P1 / P2 / S [ms] | C [ms] |
|---|---|---|
| 1 | 200 ( S ) | 200 |
| 2 | 120 / 200 ( P / S ) | 200 |
| 3 | 40 / 120 / 200 | 200 |
| 4 | 80 / 120 / 200 | 200 |
| 5 | 120 / 120 / 200 | 200 |
| 6 | 160 / 120 / 200 | 200 |
| 7 | 200 / 120 / 200 | 200 |
| 8 | 240 / 120 / 200 | 200 |
| 9 | 280 / 120 / 200 | 200 |
| 10 | 320 / 120 / 200 | 200 |
The durations of second and the last intervals are fixed at 120 msec and 200 msec, respectively, whereas the duration of the first time interval changes from 40 msec to 320 msec in steps of 40 msec. Each pattern is followed by a comparison interval of 200 msec.
The first and the second time intervals have shrinking effect on the last duration and their effects are complicated. The listener will hear a large shrinking effect when the duration of the first time interval is 120 msec (the 5th pattern) and 240 msec (the 8th pattern) and longer. In single-neighbor condition (the 2nd pattern), you can hear the second duration underestimated.
A control condition where two empty time intervals of 200 msec are presented separately is provided.
References
Nakajima,Y., ten Hoopen,G., & van der Wilk,R. (1991).
A new illusion of time perception.
Music Perception, 8, 431-448.
Nakajima,Y., ten Hoopen,G., Hilkhuysen,G., & Sasaki,. (1992).
Time-shrinking: A discontinuity in the perception of auditory temporal patterns.
Perception & Psychophysics, 51, 504-507.
Suetomi,D., & Nakajima,Y. (1997).
On the applicability of Gestalt principles to time shrinking (in Japanese).
Proceedings of the Autumn Meeting of the Acoustical Society of Japan, 425-426.
ten Hoopen,G., Hilkhuysen,R., Nakajima,Y., Yamauchi,F., & Sasaki,T. (1993).
A new illusion of time perception-II.
Music Perception, 11, 15-38.
ten Hoopen,G., Hartsiker,R., Sasaki,T., Nakajima,Y., Tanaka,M., & Tsumura,T. (1995).
Auditory isochrony: time shrinking and temporal patterns.
Perception, 24, 577-593.
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