A key figure in cochlear nonlinearity

A figure that has had a huge influence on my research, and that I still use often, is Fig. 7 from a paper entitled “Basilar-membrane responses to tones at the base of the chinchilla cochlea” (Ruggero et al., 1997, JASA 101(4), 2151–2163). This figure shows that the velocity of the response of the basilar membrane grows compressively for a tone at the characteristic frequency and linearly for tones below the characteristic frequency. This was not the first study to show this effect, but because of the technique the experimenters used, they were able to cover a larger range of input levels than some previous studies. The figure is also very clear because of the plotting style used. This type of figure has been important in psychoacoustics in explaining how masking by a masker well below a signal frequency can be used to measure compression in the cochlea.