Origins of the 'Brown Note' Urban Legend
The myth of the "brown note" is the belief that a specific, low-frequency sound can cause involuntary bowel movements in humans. The name itself is a somewhat vulgar reference to the color of human feces. While the legend has been perpetuated by pop culture, including a famous episode of South Park, its origins can be traced back to earlier sources.
One of the earliest references appears to be a satirical article published in New Scientist in 1974, which described a fictitious giant horn that supposedly induced diarrhea in an audience. This spoof, with its deadpan humor, likely contributed to the legend's spread. Additionally, military and space program experiments in the mid-20th century, exploring the effects of high-intensity infrasound on the body, might have fueled the legend's more serious, pseudoscientific appeal.
The Science Behind Infrasound
Infrasound refers to sound waves with frequencies below 20 hertz (Hz), the lower limit of typical human hearing. These are sound waves that you can often feel more than you can hear. Infrasound is all around us, created by both natural and man-made sources. Natural sources include volcanic eruptions, earthquakes, severe weather, and even elephant communication. Man-made sources include heavy machinery, traffic, HVAC systems, and wind turbines.
High-intensity infrasound can undoubtedly affect the human body, but not in the way the brown note myth claims. Scientific studies have shown that intense, low-frequency vibrations can cause a range of physiological symptoms, such as nausea, dizziness, fatigue, and a feeling of pressure in the chest. These effects are often associated with the vestibular system in the inner ear, which controls balance and spatial orientation. The discomfort is more akin to motion sickness than a specific bowel-related response.
MythBusters Puts the Myth to the Test
Perhaps the most famous debunking of the brown note came from the television show MythBusters in a 2005 episode. The hosts constructed a massive array of powerful subwoofers and generated infrasonic tones as low as 5 Hz at extremely high decibel levels (120 dB at 9 Hz). Adam Savage, the test subject, wore a protective diaper to see if the infamous effect would occur.
- The experiment: Savage was exposed to the high-intensity, low-frequency sound in a controlled environment.
- The result: He reported intense, powerful sensations, describing it as feeling like someone was "drumming on my chest." However, the experiment produced no evidence of the physiological effect promised by the legend.
- The conclusion: The MythBusters team declared the brown note myth "busted." The physical sensations were attributed to the sound waves literally moving the air around the subject's body, affecting breathing and causing general discomfort, but not activating the bowels in the way the legend suggests.
Infrasound vs. Brown Noise: Key Differences
It is important to distinguish between the mythical "brown note" and the therapeutic sound often referred to as "brown noise." This is a separate concept with a different application, often confused with the urban legend.
| Feature | Brown Note (Urban Myth) | Brown Noise (Sound Therapy) |
|---|---|---|
| Frequency | Supposedly a single infrasonic tone (e.g., 5-9 Hz) | A spectrum of sound frequencies, characterized by lower frequencies having more energy |
| Audibility | Inaudible; below the human hearing range | Audible; sounds like a low, deep rumble, similar to heavy rain or a waterfall |
| Effect | Causes involuntary bowel movements via resonance | Promotes relaxation, focus, and sleep by masking other noises |
| Scientific Basis | None; widely debunked by science and experiments | Backed by emerging research, showing promise for improving cognitive function and sleep quality |
| Application | None; a nonexistent phenomenon | Used as a relaxation or concentration aid via streaming services and apps |
The Real Effects of High-Intensity Infrasound
While the brown note is a hoax, high-intensity infrasound is a real subject of scientific study and can have noticeable health effects, although they are not specifically gastrointestinal. The human torso has various resonant frequencies, and exposure to intense infrasound can cause pressure fluctuations and vibrations that are felt throughout the body.
Studies have linked prolonged or very intense infrasound exposure to various symptoms and health concerns, particularly in occupational or residential settings near industrial sources like wind turbines. These can include:
- Dizziness and balance issues: Affecting the vestibular system in the inner ear.
- Headaches and pressure sensations: Perceived in the head or chest.
- Fatigue and sleep disturbances: Chronic exposure to low-frequency noise is a known stressor that can disrupt sleep patterns.
- Psychological discomfort: Feelings of anxiety, fear, or a sense of unease can be triggered by infrasound, even when it is not consciously heard. A famous 1998 British experiment showed that a 17 Hz tone could cause feelings of unease or fear in concertgoers.
- Potential cardiovascular effects: Some studies suggest very high levels could potentially interfere with heart muscle contractility, though this is primarily observed at extremely high lab-controlled volumes.
Conclusion: The Mythical Note vs. Reality's Resonance
In the end, the brown note remains a fictional, though highly entertaining, urban legend. The human body does not possess a specific resonant frequency in the bowels that would lead to involuntary defecation, and repeated scientific tests have failed to produce the purported effect. While high-intensity infrasound is a real and well-documented phenomenon with genuine physiological and psychological effects, these are distinct from the myth. The true science of sound is far more complex and interesting than the legend, with low-frequency vibrations impacting our bodies in subtler, but no less significant, ways.
For more in-depth scientific information on the actual effects of infrasound, explore sources like this article from the National Institutes of Health. The ongoing research into low-frequency noise continues to shed light on how our environment, even its inaudible parts, can affect our health and well-being.
