The Information in Auditory Patterns

Our remarkable ability to process information in sound is demonstrated everday as we make sense of the complex and continuous pattern of variation in the acoustic signals we encounter. The purpose of this project is to achieve a better understanding of this ability through a formal analysis of the ability to discriminate variable acoustic patterns other than speech. There are three key elements of our approach. First, all efforts are linked by a single mathematical- methodological framework where the information in a pattern is given precise meaning and listener performance is evaluated relative to a common theoretical standard. Second, the relative extent to which listeners make use of (weight) different sources of information within patterns is determined from trial-by-trial analyses of the data from each experiment. Third, a computational model that provides accurate predictions for the results of many past studies [R.A. Lutfi, J. Acoust. Soc. Am. 94, 748-758 (1993)] is recruited in the generation of specific hypotheses regarding the outcome of the proposed experiments. These three elements are combined to achieve four specific aims: (1) to provide a formal description of the interaction that causes variation in one acoustic dimension to interfere with processing of information in another, (2) to test current theories of information integration that have been proposed to account for nonadditive effects of multiple sources of interference, (3) to identify specific pattern constraints that aid in discrimination, and (4) to evaluate the listenerŐs ability to detect complex patterns of statistical variation and covariation within patterns similar to those produced by real sound sources. The results of the proposed studies are intended further our understanding of how natural redundancies in patterns aid detection in noisy backgrounds, and how listeners process invariant relations among components that define dynamic properties of patterns like those of speech and other meaningful sounds.

Selected Publications

Lutfi, R. A. (1985). A power-law transformation predicting masking by sounds with complex spectra. Journal of the Acoustical Society of America, 77, 2128-2136. * Lutfi, R. A. (1989). Informational processing of complex sound: I. Intensity Discrimination. Journal of the Acoustical Society of America, 86, 934-944. * Lutfi, R. A. (1990a). Informational processing of complex sound: II. Cross-dimensional analysis. Journal of the Acoustical Society of America, 87, 2141-2148. * Lutfi, R. A. (1990b). How much masking is informational masking? Journal of the Acoustical Society of America, 88, 2607-2610. * Lutfi, R. A. (1992). Informational processing of complex sound: III. Interference. Journal of the Acoustical Society of America, 91, 3391-3401. * Lutfi, R. A. (1993). A model of auditory pattern analysis based on component-relative- entropy. Journal of the Acoustical Society of America, 94, 748-758. * Lutfi, R. A. (1994a). Discrimination of random, time-varying spectra with statistical constraints. Journal of the Acoustical Society of America, 95, 1490-1500. * Lutfi, R. A., and Doherty, K.A. (1994). The effects of component-relative entropy on the discrimination of tone complexes. Journal of the Acoustical Society of America, 96, 3443-3450. * Lutfi, R. A., Doherty, K. A., and Oh, E. (1996). Psychometric functions for the discrimination of spectral variance. Journal of the Acoustical Society of America, 100, 2258-2265.