Demonstrations of
Auditory Illusions and Tricks

2nd Edition

Contents Introduction Chapter 1 Chapter 2 Chapter 3 Chapter 4
Chapter 5 Chapter 6 References Archives Demo Index Top Page

VI. Time Perception

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<23> Interaural and Monaural Tempo Difference
First, a series of short tones is presented monaurally at a rate of 8 tones/second, immediately followed by a similar sequence of tones presented interaurally.   Although both series are presented at identical rates, the interaurally presented series sounds subjectively slower.   This demonstrates that a sequence of auditory events that is alternated between the ears is stretched out in auditory memory, as compared with non-alternating sequences.   Previous studies revealed that the perceptual onset asynchronies of these monaural and interaural sequences differ by about 25 ms.  

ten Hoopen, G., Vos, J., & Dispa, J. (1982).
Interaural and monaural clicks and clocks: Tempo difference versus attention switching.   Journal of Experimental Psychology: Human Perception and Performance, 8, 3, 422-434.

Akerboom, S., ten Hoopen, G., Olierook, P., & van der Schaaf, T. (1983).
Auditory spatial alternation transforms auditory time.   Journal of Experimental Psychology: Human Perception and Performance, 9, 6, 882-897.


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<24> Overestimation of a Divided Time Interval
When an empty duration of 240 ms marked by two short tone bursts is divided into two empty parts by another tone burst, the whole duration can be overestimated.   However, a clear overestimation appears only when the listener perceives the divided duration as divided.   A divided duration (a) and a non-divided (empty) duration (b) can be presented.  

It may take time for these demonstrations to be presented after you click the play buttons.   In order to compare (a) and (b), please download the wave files to your computer, and play alternately.  

Hall, G.S. & Jastrow, J. (1886).
Studies of rhythm.   Mind, 11,55-62.

Nakajima, Y. (1987).
A model of empty duration perception.   Perception, 16, 485-520

Fig.24a Fig.24b

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<25> Time-Shrinking
A short empty duration immediately preceded by an even shorter empty duration can be underestimated.   Here, a fixed empty duration of 240 ms is immediately preceded by another empty duration of 80-320 ms.   In the first presentation, the preceding duration is 320 ms, and it is decreased in steps of 20 ms in the following presentations.   The second duration is perceived as if it were shortened when the preceding duration reached around 180 ms (the eighth presentation).  

Nakajima, Y., ten Hoopen, G., & van der Wilk, R. (1991).
A new illusion of time perception.   Music Perception, 8, 431-448.

Suetomi, D. & Nakajima, Y. (1998).
How stable is time-shrinking?    Journal of Music Perception and Cognition, 4, 19-25.


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<26> A Discontinuous Change in Time Perception Caused by Time-Shrinking
In the presentation of the first series (a), three sound markers define two empty durations of 160 ms each.   The first duration is decreased in steps of 10 ms, and the second duration is increased in steps of 10 ms.   Thus, the total duration is fixed at 320 ms.   When the difference between the first and the second duration is up to about 100 ms (the sixth pattern), 'time-shrinking', i.e., underestimation of the second duration caused by the presence of the first duration, takes place, and the two neighboring durations are perceived as almost identical with each other.   When the physical difference between these durations is enlarged further, time-shrinking disappears rapidly, and the difference between the neighboring durations is suddenly perceived clearly.  

This kind of sudden change of percept does not take place when the temporal order between the two durations is reversed as in the second series (b).  

Nakajima, Y., ten Hoopen, G., Hilkhuysen, G., & Sasaki, T. (1992).
Time-shrinking: A discontinuity in the perception of auditory temporal patterns.   Perception & Psychophysics, 51, 504-507.

Fig.26-1 Fig.26-2

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<27> Time-Shrinking in Patterns Consisting of Three Empty Time Intervals
In the first presentation (the control condition), two isolated empty durations of 240 ms are perceived as almost equal to each other.   In all the other presentations, three neighboring empty durations, of which the second and the third are fixed at 160 and 240 ms, are followed by an isolated empty duration of 240 ms.   The first empty duration is 40 ms in the second presentation, and increased in steps of 40 ms in the nine following presentations.   The third empty duration is underestimated when the first empty duration is 160 ms (the fifth presentation), about 300 ms (the eighth or ninth presentation), or above.  


Contents Introduction Chapter 1 Chapter 2 Chapter 3 Chapter 4
Chapter 5 Chapter 6 References Archives Demo Index Top Page