Microwave hearing, also known as the microwave auditory effect or the Frey effect, refers to a phenomenon in which a person perceives sounds or voices in their head without any external sound sources. It is a subjective auditory perception that occurs when individuals are exposed to pulsed microwave or radiofrequency signals.
The exact mechanisms behind microwave hearing are not fully understood, but there are a few proposed theories:
Thermoelastic expansion: This theory suggests that the microwave radiation absorbed by the tissues of the head can generate a small amount of heat. The rapid heating and expansion of brain tissues can create an acoustic wave that is interpreted as sound by the auditory system.
Electrostriction: According to this theory, the microwave radiation induces rapid changes in the electrical properties of neural tissue, leading to mechanical vibrations that generate auditory sensations.
Cochlear microphonics: Some researchers propose that microwave energy may directly stimulate the cochlea, the spiral-shaped structure in the inner ear responsible for hearing. This stimulation could generate sounds or auditory perceptions.
It's important to note that microwave hearing is not a widely experienced phenomenon and is primarily studied in laboratory settings. It has been reported by some individuals who have been exposed to intense or specific microwave or radiofrequency signals, such as military personnel working with radar equipment.
Microwave hearing is not considered a common occurrence in everyday life, and exposure to household microwave ovens or typical levels of electromagnetic radiation does not produce this effect. Extensive research is still ongoing to understand the underlying mechanisms and potential applications of microwave hearing.