Onset dominance in lateralization

Abstract

Saberi and Perrott [Acustica 81, 272-275 (1995)] found that the in-head lateralization of a relatively long-duration pulse train could be controlled by the interaural delay of the single pulse pair that occurs at onset. The present study examined this further, using an acoustic pointer measure of lateralization, with stimulus manipulations designed to determine conditions under which lateralization was consistent with the interaural onset delay. The present stimuli were wideband pulse trains, noise-burst trains, and inharmonic complexes, 250 ms in duration, chosen for the ease with which interaural delays and correlations of select temporal segments of the stimulus could be manipulated. The stimulus factors studied were the periodicity of the ongoing part of the signal as well as the multiplicity and ambiguity of interaural delays. The results, in general, showed that the interaural onset delay controlled lateralization when the steady state binaural cues were relatively weak, either because the spectral components were only sparsely distributed across frequency or because the interaural time delays were ambiguous. Onset dominance can be disrupted by sudden stimulus changes within the train, and several examples of such changes are described. Individual subjects showed strong left-right asymmetries in onset effectiveness. The results have implications for understanding how onset and ongoing interaural delay cues contribute to the location estimates formed by the binaural auditory system.

Lateralization of two-transient stimuli

“…This more central and perceptual characterization of the precedence effect, operating in conjunction with bandpass correlation analysis, might be capable of explaining not only lateralization data with transients, but also the findings of slow-acting and labile phenomena (Clifton, 1987;Freyman, Clifton, & Litovsky, 1991). It may also provide connections to related onset effects, such as the "restarting" of the binaural system with triggering events (Freyman et al, 1997;Hafter et al, 1988), the Franssen effect (Franssen, 1960;Hartmann & Rakerd, 1989), and the lateralization of sharply gated tones with ambiguous fine-structure cues (Abel & Kunov, 1983;Kunov & Abel, 1981). Although lateralization data with transients can be accommodated by either temporal weighting or the RG, the slow-acting and/or long-lasting onset effects just listed may require a perceptual biasing mechanism like that offered in the latter view.…”

“…Studies by Saberi and Perrott (1995) and Freyman et al (1997) both used longduration trains of transients with ambiguousBPC displays, in which multiple patterns of correlation peaks could simultaneously be seen as being roughly consistent delays across frequency. The finding of those studies was that the lateral position of such stimuli is determined completely by the interaural cue carried by the initial transient.…”

“…However, onset dominance is not limited to short-duration sounds. The precedence effect was originally discovered with continuous speech and music (Haas, 1951;Snow, 1954;Wallach et al, 1949) and has been studied in several laboratory investigations with long-duration noise and click trains (Freyman, Zurek, Balakrishnan, & Chiang, 1997;Hafter, Buell, & Richards, 1988;Saberi & Perrott, 1995). The modeling effort begun here should eventually be extended to accommodate long-duration signals.…”

Modulation Enhancement in the Electrical Signal Improves Perception of Interaural Time Differences with Bimodal Stimulation

“…ITDs in the ongoing part are dominant, unless they are ambiguous, in which case the auditory system tends to use onset cues (Buell et al 2008;Freyman et al 1997).…”

Physiological and Psychophysical Modeling of the Precedence Effect

“…Listeners have a remarkable ability to localize sounds accurately in reverberant settings, a feat attributed to the fact that they give greater perceptual weight to location cues at sound onsets, suppressing cues from later-arriving reflections (Zurek 1980;Freyman et al 1997;Devore et al 2009). This "precedence effect" (PE;Wallach et al 1949) has been studied using a range of paradigms whereby a pair of dichotic clicks is presented with a brief inter-stimulus delay (ISD).…”