Another set of researchers, Stevens and Jones (1939), thought that electrical could be transduced into sound vibrations before it reached the inner year. Hearing induced in this way has been called the electrophonic effect. They were able to determine whether a linear or non-linear transducer was involved by the presence and strength of the overtones, which were detected when the subject heard beats. The studies by Stevens and Jones (1939), as well as Jones et al (1940) indicated that when the cochlea was stimulated electrically, there were three mechanisms, which produced hearing:
1. The middle ear could act as a transducer, which obeys the ‘square law’ and convert alternations in the strength of an electrical field into the mechanical vibrations that produce sound.
2. Electrical energy could be converted into sound by a direct effect on the basilar membrane, which would then vibrate maximally at a point determined by the frequency and these vibrations would stimulate the hair cells
3. Direct stimulation of the auditory nerve produced a crude hearing sensation.
Their conclusions were basically correct, although now other body tissues have been shown to act as transducers