ASA 127th Meeting M.I.T. 1994 June 6-10

4pPP23. The measure and modelization of tempo sensitivity in auditory sequences.

Perception Auditive, Lab. de Psychol. Exp., CNRS URA 316), Univ. Rene Descartes, EPHE, 28 rue Serpente, F-75006, Paris, France

The ability of listeners to detect slight changes in the tempo of isochronous auditory sequences was investigated by measuring differential thresholds for tempi of sequences with interonset intervals (IOI) ranging from 50 to 1500 ms. The number of intervals they contained was varied systematically. A multiple-look model presented previously predicts that sensitivity increases as the number of intervals in the sequence increases, since multiple observations afford the elaboration of a more precise mental representation involving the coding of the average duration and degree of dispersion of the intervals in the sequence [C. Drake and M.-C. Botte, Percept. Psychophys. 54, 277--286 (1993)]. The results of the present study provide additional support for the multiple-look model and suggest that another parameter, that of the total duration of the sequence, should be incorporated. The multiple-look strategy can only function efficiently within a limited ``temporal window'' which depends on the tempo of the sequence. The upper limit of this temporal window is about 1 s for sequences of 50- to 300-ms IOI and about 2.5 s for sequences of 500- to 1500-ms IOI.