Audition is defined as the ability to perceive sound via an organ (i.e., the ear). This form of sensory perception can be summarized as such: vibrations are detected by the ear, and are transduced into nerve impulses that are then interpreted by the encephalon’s temporal lobe. More specifically, the eardrum essentially reduces air pressure waves to a single channel; then, in the inner ear, the way vibrations are distributed along the basilar membrane is detected by hair cells. Next, the space–time pattern of vibrations in the basilar membrane is converted to a spatial–temporal pattern of firings on the auditory nerve; finally, we arrive at the brainstem, where everything is interpreted. Hearing, then, is a form of mechanosensation; it involves information from the outside world being absorbed and processed by an organism.
However, most of us are also familiar with what may best be described as another kind of hearing – a form of inner speech that is not a response to external mechanical stimuli. Often times, when we read something or plan a sentence prior to writing it out, we can quite literally hear ourselves think – detect something that seems very much like a voice – like spoken language – reciting our thoughts.
This inner speech is imagistic. It is presently maintained that this speech imaging consists both of auditory images of spoken natural language, as well as subvocalization, which includes kinaesthetic imaging of speech production (Cole, 1997). So, essentially, hearing yourself think involves taking advantage of both speech comprehension and speech production mechanisms.
I’ve always been unable to “hear” myself yell. Try it, and I think you’ll see just how difficult mentally producing a raised voice is. Why can’t one effectively internally represent the idea of lowered or elevated volume?