Toggle Main Menu Toggle Search

Open Access padlockePrints

Detection and direction-discrimination of diotic and dichotic ramp modulations in amplitude and phase

Lookup NU author(s): Michael Simpson, Professor Adrian ReesORCiD, Dr Gary Green


Full text for this publication is not currently held within this repository. Alternative links are provided below where available.


When the source of a tone moves with respect to a listener's ears, dichotic (or interaural) phase and amplitude modulations (PM and AM) are produced. Two experiments investigated the psychophysical characteristics of dichotic linear ramp modulations in phase and amplitude, and compared them with the psychophysics of diotic PM and AM. In experiment 1, subjects were substantially more sensitive to dichotic PM than diotic PM, but AM sensitivity was equivalent in the dichotic and diotic conditions. Thresholds for discriminating modulation direction were smaller than detection thresholds for dichotic AM, and both diotic AM and PM. Dichotic PM discrimination thresholds were similar to detection thresholds. In experiment 2, the effects of ramp duration were examined. Sensitivity to dichotic AM and PM, and diotic AM increased as duration was increased from 20 ms to 200 ms. The functions relating sensitivity to ramp duration differed across the stimuli; sensitivity to dichotic PM increased more rapidly than sensitivity to dichotic or diotic AM. This was also reflected in shorter time-constants and minimum integration times for dichotic PM detection. These findings support the hypothesis that the analysis of dichotic PM and AM rely on separate mechanisms. © 2003 Acoustical Society of America.

Publication metadata

Author(s): Witton C, Simpson MIG, Henning GB, Rees A, Green GGR

Publication type: Article

Publication status: Published

Journal: Journal of the Acoustical Society of America

Year: 2003

Volume: 113

Issue: 1

Pages: 468-477

ISSN (print): 0001-4966

ISSN (electronic): 1520-8524

Publisher: Acoustical Society of America


DOI: 10.1121/1.1525286

PubMed id: 12558284


Altmetrics provided by Altmetric