title: Isolating spectral cues in amplitude and quasi-frequency modulation discrimination by reducing stimulus duration.
abstract: This study investigated the psychophysical effects of distortion products in a listening task traditionally used to estimate the bandwidth of phase sensitivity. For a 2000 Hz carrier, estimates of modulation depth necessary to discriminate amplitude modulated (AM) tones and quasi-frequency modulated (QFM) were measured in a two interval forced choice task as a function modulation frequency. Temporal modulation transfer functions were often non-monotonic at modulation frequencies above 300 Hz. This was likely to be due to a spectral cue arising from the interaction of auditory distortion products and the lower sideband of the stimulus complex. When the stimulus duration was decreased from 200 ms to 20 ms, thresholds for low-frequency modulators rose to near-chance levels, whereas thresholds in the region of non-monotonicities were less affected. The decrease in stimulus duration appears to hinder the listener's ability to use temporal cues in order to discriminate between AM and QFM, whereas spectral information derived from distortion product cues appears more resilient.
authors.affiliation: Department of Cognitive Sciences, 2201 Social & Behavioral Sciences Gateway Building (SBSG), University of California, Irvine, CA 92697-5100, USA. Electronic address: eborucki@uci.edu.
authors.forename: Ewa
authors.initials: E
authors.lastname: Borucki
authors.affiliation: Department of Cognitive Sciences, 2201 Social & Behavioral Sciences Gateway Building (SBSG), University of California, Irvine, CA 92697-5100, USA.
authors.forename: Bruce G
authors.initials: BG
authors.lastname: Berg
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D001301:Audiometry, Pure-Tone / Q000379:methods*; D001307:Auditory Perception / Q000502:physiology*; D001309:Auditory Threshold; D003463:Cues; D006801:Humans; D010897:Pitch Discrimination; D011571:Psychoacoustics; D013018:Sound Spectrography; D013998:Time Perception; D055815:Young Adult
keywords: Amplitude modulation; Bandwidth; Cubic distortion tone; Distortion products; Duration; Phase sensitivity