8,700 Studies Reviewed. 87.0% Found Biological Effects. The Evidence is Clear.
Shield Your Body
Symptoms & Sensitivity

Microwave Hearing: Evidence for Thermoacoustic Auditory Stimulation by Pulsed Microwaves

Bioeffects Seen

H. H. Seliger, W. M. Bigelow, J. P. Hamman · 1974

Share:

Pulsed microwaves can create audible clicks in your head through thermoacoustic conversion without tissue heating.

Plain English Summary

Summary written for general audiences

Scientists demonstrated that pulsed microwave energy can create acoustic clicks in water through rapid heating, explaining why people hear clicking sounds when exposed to microwave radiation. The effect requires moderately intense pulses (0.5-5 watts per square centimeter) but occurs without measurable tissue heating, making it the only confirmed biological effect of microwaves that doesn't involve thermal damage.

Why This Matters

This groundbreaking 1974 study revealed something remarkable: your body can literally convert microwave energy into sound. When pulsed microwaves hit your head, they create tiny pressure waves in tissue water that your inner ear perceives as clicks. What makes this finding particularly significant is that it happens at power levels well below those that cause tissue heating - challenging the long-held assumption that thermal effects are the only biological concern with microwave exposure. The reality is that modern wireless devices operate using similar pulsed microwave signals, though typically at much lower power levels than those used in this study. This research opened the door to understanding non-thermal biological effects of electromagnetic fields, a concept that remains contentious in EMF health debates today.

Exposure Information

Specific exposure levels were not quantified in this study.

Cite This Study
H. H. Seliger, W. M. Bigelow, J. P. Hamman (1974). Microwave Hearing: Evidence for Thermoacoustic Auditory Stimulation by Pulsed Microwaves.
Show BibTeX
@article{microwave_hearing_evidence_for_thermoacoustic_auditory_stimulation_by_pulsed_mic_g5171,
  author = {H. H. Seliger and W. M. Bigelow and J. P. Hamman},
  title = {Microwave Hearing: Evidence for Thermoacoustic Auditory Stimulation by Pulsed Microwaves},
  year = {1974},
  
  
}

Quick Questions About This Study

Yes, pulsed microwave energy creates acoustic transients in tissue water that the ear perceives as clicks synchronized with each pulse. This thermoacoustic effect occurs through rapid microscopic heating and expansion without measurable temperature increase in tissues.
The study found that moderately intense pulses of 0.5 to 5 watts per square centimeter at the head surface can produce audible clicks. These levels are much higher than typical wireless device exposures today.
No, microwave hearing occurs without observable tissue heating. Each 50-microsecond pulse causes less than one-millionth of a degree temperature increase, making this the only confirmed non-thermal biological effect of microwave radiation.
Pulsed microwave energy causes rapid microscopic heating in water, creating thermal expansion that generates acoustic pressure waves within the audible frequency range. These pressure transients are what people perceive as clicking sounds.
This effect proves that microwave radiation can have biological impacts without causing tissue heating, challenging the thermal-only safety model. It demonstrates that electromagnetic fields can interact with biological systems through non-thermal mechanisms.