Non-Linearity in a Computational Model of the Response of the Basilar Membrane

Abstract

We are interested in modelling human response to speech signals with particular reference to selective attention. We intend that our models should use principles derived from anatomy and physiology as far as possible. Accordingly, a balance has to be struck hetween available computational power and the need to model all the important subsidiary processes such as middle- and outer- ear effects, basilar membrane response, inner hair-cell response, interactions among neurons in the bminstem nuclei, etc .. Despite the computational overhead of taking it into account. the nonlinearity of the response of the inner ear to sound is important to an understanding of human speech processing for at least two reasons. Firstly, we know that distortion products influence pitch perception - the so-called second effect of pitch shift (Schouten e/ al., 1962) - and pitch is an important element in the segregation of sounds. Secondly, the nonlinear response of the cochlea has important implications for the representation of speech sounds (Miller and Sachs, 1983).