title: Across-ear interference from parametrically degraded synthetic speech signals in a dichotic cocktail-party listening task.
abstract: Recent results have shown that listeners attending to the quieter of two speech signals in one ear (the target ear) are highly susceptible to interference from normal or time-reversed speech signals presented in the unattended ear. However, speech-shaped noise signals have little impact on the segregation of speech in the opposite ear. This suggests that there is a fundamental difference between the across-ear interference effects of speech and nonspeech signals. In this experiment, the intelligibility and contralateral-ear masking characteristics of three synthetic speech signals with parametrically adjustable speech-like properties were examined: (1) a modulated noise-band (MNB) speech signal composed of fixed-frequency bands of envelope-modulated noise; (2) a modulated sine-band (MSB) speech signal composed of fixed-frequency amplitude-modulated sinewaves; and (3) a "sinewave speech" signal composed of sine waves tracking the first four formants of speech. In all three cases, a systematic decrease in performance in the two-talker target-ear listening task was found as the number of bands in the contralateral speech-like masker increased. These results suggest that speech-like fluctuations in the spectral envelope of a signal play an important role in determining the amount of across-ear interference that a signal will produce in a dichotic cocktail-party listening task.
authors.affiliation: Air Force Research Laboratory, AFRL/HECB, WPAFB, Ohio 45433, USA. douglas.brungart@wpafb.af.mil
authors.forename: Douglas S
authors.initials: DS
authors.lastname: Brungart
authors.forename: Brian D
authors.initials: BD
authors.lastname: Simpson
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Darwin
authors.forename: Tanya L
authors.initials: TL
authors.lastname: Arbogast
authors.forename: Gerald
authors.initials: G
authors.lastname: Kidd
mesh_terms: D000328:Adult; D004007:Dichotic Listening Tests; D004432:Ear, Middle / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010470:Perceptual Masking / Q000502:physiology; D012931:Social Environment; D013067:Speech Perception; D013071:Speech, Alaryngeal