William M. Siebert
Res. Lab. of Electron., Rm. 36-825, MIT, Cambridge, MA 02139
In 1951, Harvey Fletcher published a comprehensive analysis of the macromechanical dynamic behavior of the cochlear partition in response to sound. Although not the first to derive the now-familiar one-dimensional long-wave differential equation, Fletcher's discussion is so clear and so careful that it had considerable impact at the time and remains today a model of elegant biophysical thinking. His results, moreover, matched the observations then available (primarily those of von Bekesy). The last 44 years, however, have seen the introduction of a variety of new experimental observations casting serious doubts on whether the cochlea can usefully be considered a linear passive system as Fletcher and his contemporaries assumed. And new analytical tools, notably the wide availability of extensive computational facilities, have substantially altered our idea of what constitutes a workable mathematical model. This paper will review the place of models of the Fletcher type in our current understanding of cochlear behavior.