Auditory temporal processing

) Sounds, by their very nature, are events that take time to unfold. Much of hearing science has been devoted to the processes involved in detecting sounds, discriminating and identifying them, or locating them in space. The proposed research specifically targets temporal processes in hearing. Does the perceptual processing of one sound in some way contaminate the perceptual processing of temporally adjacent sounds? If so, in what ways? How truthful to the actual state of the physical stimulus is the unfolding of our private, subjective experience of the auditory world? How do we appropriately measure the resolution with which our auditory experience unfolds? The proposed research tackles these questions directly. One line of the research is on selective adaptation in hearing. It explores how experience of a sound at one point along a dimension (e.g., location) shifts sensitivity along that dimension for the next sound that occurs. A second line of research is on the saltation illusion. It explores how information about one sound can affect the processing of information about a temporally proximate sound, including the case of the perception of one sound being affected by the occurrence of a later sound. Our third line of research seeks an empirical answer to a methodological question. Currently, at least two psychophysical methods are being employed to measure what are called "auditory gap detection thresholds." These thresholds are measures of the shortest detectable period of silence between two sounds, and are thus a measure of auditory temporal acuity. But do the two methods actually measure the same parameter of perceptual performance? We suspect that they don't, but that needs to be proved experimentally. Together, these lines of enquiry build on the breakthroughs made in the preceding two grant cycles, and offer new insights into the temporal properties of processing within the human auditory system.