The “brown note” is an urban legend suggesting a specific infrasonic frequency could cause involuntary defecation. This concept sparks curiosity about its reality and scientific validity. This article explores the origins and popular understanding of the “brown note” before delving into the scientific evidence surrounding infrasound and its actual effects on the human body.
The Brown Note Myth
The “brown note” is widely understood as a hypothetical low-frequency sound capable of inducing involuntary bowel movements, often leading to nausea and general discomfort. This alleged effect is attributed to the sound causing acoustic resonance within the human digestive system. The myth has gained significant traction and cultural impact, popularized by television shows like South Park. The core idea behind the myth is that a specific low-frequency sound, typically placed in the infrasound range (below 20 Hz), could vibrate the internal organs, particularly the bowels, to such an extent that it results in a loss of control. The alleged frequencies associated with the brown note are often cited as being between 5 and 9 Hz, which is below the threshold of human hearing.
The Science of Infrasound
Infrasound refers to sound waves with frequencies below the typical human hearing range, which is 20 Hertz (Hz). While humans cannot consciously hear these very low frequencies, they can sometimes perceive them as vibrations through other parts of the body, particularly at higher intensities. These low-frequency waves can travel long distances with minimal energy loss and can penetrate solid structures.
Infrasound is naturally produced by various phenomena, including earthquakes, volcanic eruptions, severe weather events like thunderstorms and tornadoes, and even large animals such as elephants and whales for communication over vast distances. Human activities also generate infrasound from industrial processes like wind turbines, heavy machinery, and large explosions.
Scientific investigations into the effects of infrasound on humans have shown that while it can cause certain physiological responses, involuntary defecation is not among them. Exposure to high levels of infrasound can lead to feelings of discomfort, anxiety, unease, fatigue, and even slight nausea or pressure changes within the body. For instance, a notable experiment conducted by the television show MythBusters tested the brown note claim by exposing a subject to high-intensity infrasound, some reaching 120 decibels at 9 Hz. Although the subject reported some physical anxiety and shortness of breath due to the rapid air movement, the rumored physiological effects of involuntary bowel movements did not occur, leading the show to declare the myth “busted”. While infrasound can indeed affect the human body, the specific “brown note” that causes involuntary defecation is not supported by scientific evidence.