Old plus new: The interplay of regularly extraction and auditory object formation
Final Report Abstract
During my one-year post-doctoral fellowship, I had the opportunity to conduct research in the group of Prof. Dr. István Winkler at the Institute for Psychology of the Hungarian Academy of Sciences in Budapest. We investigated principles of auditory scene analysis: the decomposition of the mixture of sounds arriving at our ears into meaningful signals emitted from different sources (such as separating speech and background music in a movie). This source segregation is something that a human listener can perform without difficulty in most situations, while technology still falls short of human capacities. It seems that our knowledge on the auditory cues that we are using for source segregation is still limited. For this reason, we conducted several behavioral and electrophysiological experiments to investigate the importance of a so-far neglected cue in auditory scene analysis: the extraction of regular patterns from the auditory input. The underlying reasoning was that each source has its own characteristic emission pattern (e.g., due to constraints of a speaker’s vocal tract) and that the signals emitted by a given source typically change in a regular manner (e.g., due to movement). Such characteristics could, in principle, be picked up by a regularity-extracting system and be used for tracking a given source. We wanted to find out whether the auditory system actually uses such a strategy, and were indeed successful in showing that regularities can be extracted from sounds whose grouping by other auditory cues is impossible. Furthermore, we were able to demonstrate that the extracted regularities within a stream of sounds stabilize its perception as a distinct auditory source. We then went on to investigate the interplay of regular patterns with previously established cues of auditory scene analysis. We obtained evidence for bi-directional interactions between the different types of cues. This is consistent with the literature suggesting at least two levels of auditory grouping. Our results illustrate the importance of pre-attentive regularity extraction in auditory object formation. Follow-up experiments are under way to address in more detail the temporal and functional relation of these processes, and to determine the extent to which these mechanisms are already present at birth. Results will continue to advance our understanding of auditory perception in natural situations, and will be relevant for technical applications such as hearing aids, communication devices, and human-computer interfaces.
Publications
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(2009). Erkennung von Regeln in der akustischen Umwelt [Detection of regularities in the acoustic environment]. Symposium organized by Alexandra Bendixen at the “35. Arbeitstagung Psychophysiologie und Methodik“ (APM 2009)
Bendixen, A.
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(2009). I heard that coming: Event-related potential evidence for stimulus-driven prediction in the auditory system. Journal of Neuroscience, 29, 8447-8451
Bendixen, A., Schröger, E. & Winkler, I.
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(2009). Regularity extraction and stimulus prediction in dynamically changing acoustic environments. Symposium organized by Erich Schröger, Torsten Baldeweg, & Sue Denham at the Fifth Conference on Mismatch Negativity (MMN) and its Clinical and Scientific Applications
Bendixen, A.
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(2010). Probability dependence and functional separation of the object-related and mismatch negativity eventrelated potential components. NeuroImage, 50, 285-290
Bendixen, A., Jones, S.J., Klump, G., & Winkler, I.
