The precedence effect for lateralization at low sensation levels

• Published in: Hearing research Vol. 148; no. 1; pp. 88 - 94
• Main Authors: Goverts, S.Theo, Houtgast, Tammo, van Beek, Hans H.M.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.10.2000; Elsevier
• Subjects: Acoustic Stimulation - methods; Adult; Auditory perception; Auditory Perception - physiology; Auditory Threshold - physiology; Binaural hearing; Biological and medical sciences; Cues; Dichotic Listening Tests; Ear and associated structures. Auditory pathways and centers. Hearing. Vocal organ. Phonation. Sound production. Echolocation; Functional Laterality - physiology; Fundamental and applied biological sciences. Psychology; Hearing - physiology; Humans; Lateralization accuracy; Localization dominance; Noise; Normal hearing; Perceptual Masking - physiology; Precedence effect; Reference Values; Vertebrates: nervous system and sense organs; Localization dominance; Lateralization accuracy; Precedence effect; Binaural hearing; Normal hearing; Auditory perception; Human; Acoustic stimulus; Stimulus localization; Dominance; Perception; Laterality; Stimulus position
• ISSN: 0378-5955; 1878-5891
• DOI: 10.1016/S0378-5955(00)00143-X

Using dichotic signals presented by headphone, stimulus onset dominance (the precedence effect) for lateralization at low sensation levels was investigated for five normal hearing subjects. Stimuli were based on 2400-Hz low pass filtered 5-ms noise bursts. We used the paradigm, as described by Aoki and Houtgast (Hear. Res., 59 (1992) 25–30) and Houtgast and Aoki (Hear. Res., 72 (1994) 29–36), in which the stimulus is divided into a leading and a lagging part with opposite lateralization cues (i.e. an interaural time delay of 0.2 ms). The occurrence of onset dominance was investigated by measuring lateral perception of the stimulus, with fixed equal duration of leading and lagging part, while decreasing absolute signal level or adding a filtered white noise with the signal level set at 65 dBA. The dominance of the leading part was quantified by measuring the perceived lateral position of the stimulus as a function of the relative duration of the leading (and thus the lagging) part. This was done at about 45 dB SL without masking noise and also at a signal-to-noise ratio resulting in a sensation level of 10 dB. The occurrence and strength of the precedence effect was found to depend on sensation level, which was decreased either by lowering the signal level or by adding noise. With the present paradigm, besides a decreased lateralization accuracy, a decrease in the precedence effect was found for sensation levels below about 30–40 dB. In daily-life conditions, with a sensation level in noise of typically 10 dB, the onset dominance was still manifest, albeit degraded to some extent.