, Volume 70, Issue 8, pp 1558-1570

One sound or two? Object-related negativity indexes echo perception

Abstract

The ability to isolate a single sound source among concurrent sources and reverberant energy is necessary for understanding the auditory world. The precedence effect describes a related experimental finding, that when presented with identical sounds from two locations with a short onset asynchrony (on the order of milliseconds), listeners report a single source with a location dominated by the lead sound. Single-cell recordings in multiple animal models have indicated that there are low-level mechanisms that may contribute to the precedence effect, yet psychophysical studies in humans have provided evidence that top-down cognitive processes have a great deal of influence on the perception of simulated echoes. In the present study, event-related potentials evoked by click pairs at and around listeners' echo thresholds indicate that perception of the lead and lag sound as individual sources elicits a negativity between 100 and 250 msec, previously termed the object-related negativity (ORN). Even for physically identical stimuli, the ORN is evident when listeners report hearing, as compared with not hearing, a second sound source. These results define a neural mechanism related to the conscious perception of multiple auditory objects.

The research reported here was partially funded by NIH Grant R01 DC01625 awarded to R.E.K. and R.L.F. as well as by NIH Institutional Training Grant MH16745, which provided postdoctoral training for A.S.J. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIDCD, NIMH, or NIH. We thank Lori Astheimer, William Bush, Molly Chilingerian, Ahren Fitzroy, Jim Morgante, and Leah Novotny for assistance with data collection.
Note—Accepted by the editorial board of Editor-Elect Jeremy M. Wolfe.