The studies done in the late 20th century have proven the Frequency Theory incorrrect in its assumption of the firing rate of the auditory nerve. The said time domain representation, as well as the frequency analysis, is theorized to be processed in the brain, rather than in the inner ear. This assumption is important in relation to the theory's suggestion that the incoming sound waveform has a time domain representation that is associated with the manner or rate at which the auditory nerve fires. The theory gives an assumption that the firing rate of the auditory nerve has a wide range of 20 to 20,000 times per second. Their theories were known as telephone theories due to the similarity between the waveform of speech sound in a telephone line and the incoming sound signal to the human brain.
Rinne (1865) and Rutherford (1880) proposed the early forms of the Frequency theory of hearing. Perception of sound stimuli accounting for low frequencies are associated with the frequency theory. This process is also called frequency place-mapping.Ĭritics of the Place Theory of hearing argued that most often than not, characteristic frequencies are hard to determine below 120 Hz.
For instance, if a sound stimulus has a tone of 300 Hz, the part of the basilar membrane that has a CF of 300 Hz would be stimulated.
The basilar membrane of the ear resonates the sound with a corresponding characteristic frequency or CF. The inner serves as a tuned resonator that passes the spectral representation to the brainstem, and then to the auditory cortex via the auditory nerve. Helmholtz' modern theory of hearing states that incoming sounds from the environment are, in a spectral representative form, extracted by the inner ear. But, it is worthy to note that crude forms of the Place Theory had been created as early as 1605. Also known as the Resonance Theory, this theory was proposed by Helmholtz in 1857.
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