1. A method for enhancing a cochlear implant's spectral contrast using a computerized fitting system, the method comprising: providing from the fitting system acoustic signals with different frequency spectrums to a cochlear implant implanted in a user; receiving at the fitting system user responses to the acoustic signals, wherein the responses indicate the user's ability to discriminate between frequencies in a spectrum; determining in the fitting system a transfer function of the cochlear implant based upon the user's responses; and configuring the cochlear implant, based on the transfer function, to modify at least one contrast between frequencies processed by a processor in the cochlear implant.