Known simply as “the Hum” to Kokomo residents, this phenomena has plagued the “City of Firsts” since 1999, when reports of an endless, barely-audible monotonous Hum began trickling in. And not just in Kokomo.

Hundreds of cities across the country began reporting a similar rumble, described by sufferers as a large engine idling in the distance, or the rush of an underground river, or the inner ear’s drone when covering one’s ears (the flesh of your hands filters out high-pitched ambient noise, leaving only low-pitched sound).

The variety of similes used to describe the Hum aside, sufferers all agreed it was persistent and low-pitched (around 20 Hz). Quiet, but audible enough to cause discomfort, headaches, and, in some cases, vomiting and migraines. Despite the very visible effects of this phenomena, audiologists have been unable to reach a consensus on the source of the Hum, or if it even exists in the first place.

Maybe Mass Hysteria?

When contacted two decades ago, researchers considered mass hysteria the most likely cause of the Kokomo Hum. Mass hysteria is common, well-documented, and, most of all, very contagious.  During the Dancing Plague of 1518, 400 people uncontrollably danced for a days at a stretch and by the time the incident ended months later, dozens of people had died from malnutrition, exhaustion, and cardiac trauma. From dancing.

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In the mid-1940s, the Mad Gasser of Mattoon (Illinois) hysteria caused citizens to become violently ill after choking on imagined odors in their homes. Conducting an exhaustive search, Mattoon police found no trace of a “Mad Gasser” and dismissed it as mass hysteria. 


Probably the most infamous case of hysteria for Hoosiers was the 1978 tragedy at Jonestown, in which a drug-addled and delusion Jim Jones brainwashed nearly a thousand followers, including many from the Indianapolis area, and coerced them into committing mass suicide. It was the largest loss of American civilian lives until 9/11 in 2001.

The Kokomo Hum, however, cannot be so easily dismissed, because possible causes and the effects of infrasound (extreme low-frequency) are indisputable. Studies on the physical effects of infrasound—sound waves at or below 20 Hz—on humans have shown effects ranging from feelings of dread or fear to insomnia to gastrointestinal stress to violent nausea. This typically depends on the subject’s hearing acuity; not everyone can hear such a low-frequency noise.


Serious and Disciplined Study

At the forefront of this mystery is Dr. Glen MacPherson, whose hard work and rigid adherence to scientific standards have kept the Hum from falling into the trash bin of pseudoscience. Dr. MacPherson, former lecturer at the University of British Columbia, mathematics educator, ethnographic researcher, and curriculum advisor for UBC’s Robson Campus, is the real deal.

After first hearing the Hum in 2012 in Canada, he discovered no database existed to collected data of the phenomena. He quickly established the World Hum Map and Database Project, which utilizes strict self-reporting to catalog Hum experiences across the world. A daunting task, Dr. MacPherson does his best with the site’s self-reported data to an admirable degree. Self-reporting is a notoriously difficult method of data collection (it can often be misleading, incomplete, or inconclusive).

The World Hum database warns visitors clearly: “This is a place for disciplined inquiry, and not for wild speculation and conspiracy. There are many entertaining and interesting websites available for those who want to indulge in those activities.”

Because of his efforts, greater numbers of professional audiologists have taken an interest in the Hum, although he still has detractors. Dr Jonathan Hazell, head researcher for the United Kingdom’s Royal National Institute for Deaf People, didn’t mince words when asked about the Hum: “Rubbish. Everybody who has tinnitus complains at first of environmental noise. ‘Hummers’ are a group of people who cannot accept that they have tinnitus.”

Dr. MacPherson didn’t dismiss the phenomena so readily.

Dr. MacPherson’s Hypotheses


To be sure, Dr. MacPherson’s evidence isn’t refined enough to produce a definitive conclusion concerning the Hum phenomena in his native Canada, in Europe, or in Kokomo, Indiana. It does allow some educated guesses that may guide more comprehensive study in the future. Considering he has done this with his own money on his own time, and with donations marginally covering the database’s ad-free hosting, the site’s contribution is significant.

By his estimate, only 2% to 4% of the world’s population has hearing sensitive enough to detect the low-frequency Hum and live in an environment conducive to detecting low-pitched ambient noise. White noise such as a running fan or climate control machinery can easily mask the sound. “Hearers” or “Hummers,” as they are sometimes called, generally report the Hum louder during the night than in the day, and even more easily detected indoors than outside. Sadly, those combined features make sleeping difficult, a common complaint.