Continuous versus discrete frequency changes: different detection mechanisms?
The Journal of the Acoustical Society of America. 2009-02-01; 125(2): 1082-1090
DOI: 10.1121/1.3050271
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1. J Acoust Soc Am. 2009 Feb;125(2):1082-90. doi: 10.1121/1.3050271.
Continuous versus discrete frequency changes: different detection mechanisms?
Demany L(1), Carlyon RP, Semal C.
Author information:
(1)Laboratoire Mouvement, Adaptation, Cognition UMR CNRS 5227, Universite de
Bordeaux, Bordeaux, France.
Sek and Moore [J. Acoust. Soc. Am. 106, 351-359 (1999)] and Lyzenga et al. [J.
Acoust. Soc. Am. 116, 491-501 (2004)] found that the just-noticeable frequency
difference between two pure tones relatively close in time is smaller when these
tones are smoothly connected by a frequency glide than when they are separated by
a silent interval. This « glide effect » was interpreted as evidence that frequency
glides can be detected by a specific auditory mechanism, not involved in the
detection of discrete, time-delayed frequency changes. Lyzenga et al. argued in
addition that the glide-detection mechanism provides little information on the
direction of frequency changes near their detection threshold. The first
experiment reported here confirms the existence of the glide effect, but also
shows that it disappears when the glide is not connected smoothly to the
neighboring steady tones. A second experiment demonstrates that the direction of
a 750 ms frequency glide can be perceptually identified as soon as the glide is
detectable. These results, and some other observations, lead to a new
interpretation of the glide effect, and to the conclusion that continuous
frequency changes may be detected in the same manner as discrete frequency
changes.
DOI: 10.1121/1.3050271
PMID: 19206883 [Indexed for MEDLINE]