Experiments with a computational model of the cochlea

A computational model of the cochlea has been subjected to a number of experiments to clarify its relation to psychophysical and physiological reality. The experiments are useful in calibrating the model, but more importantly, they are useful in explaining how seemingly contradictory data can be accounted for by simple mechanisms. For example, measurements of threshold tuning curves and masking functions show clearly that threshold tuning curves are sharper than the cochlear mechanical filter transfer functions, without requiring a second tuned mechanism. Similarly, critical bandwidths or spread of masking are seen to be wider than the filter transfer functions. These effects are shown to be consequences of the coupled automatic gain control model which was originally introduced as an aid to handling a large dynamic range; the AGC's effect on tuning is a side effect.