Signals, cochlear mechanics and pragmatism: a new vista on human hearing?

Abstract

The sense of hearing in humans became a research field in its own right around the middle of the nineteenth century. The foundations of the field were laid by physicists such as Georg Ohm and Hermann von Helmholtz and by the physiologist Alfonso Corti. The concepts of pure tone and Fourier analysis have informed hearing research ever since. The miracle of our exquisite capacity for perceiving salient qualities of music and speech such as pitch and prosody has often been explained in terms of Fourier analysis of acoustic stimuli into pure tones. In this article, I combine a historical–philosophical approach with acoustic signal modelling, cochlear mechanics and qualitative experiment. I discuss auditory phenomena irreducible to Fourier analysis of acoustic stimuli and reappraise the conceptual foundations of the field by proposing a pragmatist framework for understanding the sense of hearing in humans.

Keywords:

• signals
• hearing
• Corti
• Helmholtz
• Fourier analysis
• pragmatism

Notes

Notes

1. …oder, da ihr Klang keine weitere Zusammensetzung aus verschiedenen Tönen hören lässt (Helmholtz 1877, p. 38).

2. In recent years, outer hair cell function and biochemical and electromechanical properties have become the subject of more and more intense scrutiny, made possible in part by the advent of laser velocimetry, for example, see Nowotny and Gummer (2006) and the bibliography reported by these authors.

3. Malmierca and Irvine (2005, p. 1) state in their introduction: ‘[i]t is the aim of this volume to provide a comprehensive overview of the neural mechanisms of auditory spectral processing and of the way in which spectral information is used by human listeners to generate their auditory perception of the world around them’.

4. Example sound files of a 1 Hz square wave and its many Fourier approximations have been synthesised by the author. The author will provide them to readers upon request.

5. It is of course conceivable that as we learn more about cochlear biomechanics and about the outer hair cells responsible for controlling the motions of the organ of Corti, it will turn out that not all of the parameters of the model can be controlled by the outer hair cells, or that not all of them can be controlled to the same extent. It is a well-known result in control theory that controllability cannot be taken for granted since it depends on the physics of both the system to be controlled and the controller.