The distinction between inner thoughts and external sounds is a fundamental aspect of human perception. While it is difficult to prove subjectively what others experience, the understanding of how our auditory system works and how the brain processes information can provide some insights into this distinction. Here are some reasons that help us understand why we don't hear our own inner thoughts as external sounds:
Anatomy of the Auditory System: The human auditory system is designed to process sound waves that travel through the air and vibrate the eardrum. The sound waves are then converted into electrical signals that travel to the brain through the auditory nerve. Inner thoughts, on the other hand, arise from neural activity within the brain and do not generate sound waves in the external environment.
Lack of External Stimulus: When we hear external sounds, they are caused by vibrations in the air or other physical mediums. However, inner thoughts are not generated by external stimuli but rather by the activation and interaction of neural circuits within the brain.
Brain Activity: Neuroimaging studies have shown that different regions of the brain are activated when we process external sounds compared to when we engage in internal thought processes. For instance, the auditory cortex is activated when processing external sounds, while the prefrontal cortex and other areas of the brain are involved in generating and processing thoughts.
Mental Imagery: While inner thoughts might sometimes involve a form of mental imagery or "inner speech," it is important to note that this is a cognitive phenomenon, not a physical sound in the external world. Mental imagery relies on brain activity and neural representations rather than actual sound waves.
Subjective Experience: The subjective experience of hearing external sounds is distinct from the experience of having inner thoughts. Most individuals can differentiate between external sounds and their internal mental processes based on the characteristics of the perception and the absence of any external auditory input.
It's essential to remember that human perception and consciousness are complex processes that are still not fully understood. While we can explain the general distinctions between hearing external sounds and experiencing inner thoughts, the precise mechanisms of consciousness and thought perception remain active areas of scientific investigation.