The purpose of the proposed research is to provide new insights fundamental to the understanding of the lateralization dominance aspect of the precedence effect. The experiments are especially designed to aid in the evaluation and applicability of a new model that we have recently shown to provide a quantitative account for lateralization dominance as measured in earphone-based laboratory studies with pairs of binaural transients. The model combines peripheral interactions (e.g., auditory filtering, compression, rectification, adaptation) with cross-correlation and across-frequency integration. It makes clear that stimulus-based interactions within monaural peripheral filters greatly alter the external interaural temporal disparities (ITDs) and interaural intensitive disparities (liDs) such that the internal, effective ITDs and liDs are drastically different than those at the input. We have also shown that compression and adaptation as incorporated within Meddis' (1986) hair-cell model allows one to capture the behavioral data. The behavioral experiments proposed flow directly from those observations and are designed to answer the following questions: How is the strength of precedence affected by changes in the duration or in the levels of the stimuli? How do these stimulus parameters interact with each other and with the time between the leading and lagging components in terms of their effects on precedence? How much do the higher frequency regions contribute to precedence. In order to answer these questions, we propose to measure lateralization dominance via an acoustic pointing task while systematically varying the levels (overall and/or relative), the durations (overall and/or relative), the times between the leading and lagging pairs of binaural transients, and the extent of the frequency spectrum that conveys the relevant binaural information. The behavioral data will not only help to evaluate the contribution of peripheral processing to precedence phenomena, they will also constitute a comprehensive set of observations important to our understanding of binaural processing. The potential health benefits of this program of research are a better understanding of how the ear and brain process information and the potential for """"""""better"""""""" diagnostic procedures that may, eventually, have clinical significance.
| Bernstein, Leslie R; Trahiotis, Constantine (2005) Measures of extents of laterality for high-frequency ""transposed"" stimuli under conditions of binaural interference. J Acoust Soc Am 118:1626-35 |
| Grange, A N; Trahiotis, C (1996) Lateral position of dichotic pitches can be substantially affected by interaural intensitive differences. J Acoust Soc Am 100:1901-4 |
