Navel Lint Studies

The following is an article from The Annals of Improbable Research, now in all-pdf form. Get a subscription now for only $25 a year!

by Karl S. Kruszelnicki
Julius Sumner Miller Fellow
The Science Foundation for Physics, School of Physics,
The University of Sydney, Sydney, Australia

(Image credit: Enoch Lau)

It is extremely gratifying to see a newcomer—Georg Steinhauser of Vienna University of Technology—enrich the slowly growing field of belly button lint studies.

My introduction to the field began innocently with a “simple” question on my Triple J Science Talkback radio show (Thursdays, 11:00–12:00 Australian Eastern Standard Time), way back in 2000. The caller asked, “Why is my belly button fluff blue—and why do I get it, anyhow?” This was a real question, which deserved a real answer. I didn’t have that answer, so I went looking. I found that the British Medical Association News Review posed this very question to its readers, and then Tim Albert published their answers about belly button fluff (BBF) on p. 17 of the August 1984 issue in an article called “Blue Jokes—Readers probe the mysteries of the navel.”

Michael Biesecker also discussed belly button fluff in the 19 April 1995 issue of Technician. His theory was similar to Tim Albert’s: the process involves fibers leaving the clothes and being funneled to the belly, where they coalesce into balls of lint.

So when, in 2001, I was asked the same question again, I was able to quote the fruits of my labor. But this was all hypothesis, with no experimentation or survey.

I was shamed into action by Doug, from the Soft Bottom Inshore Fish Habitats Research Team.

After shaving a 10 cm radius around his navel, Doug suddenly stopped generating BBF. As his belly hair regrew, the BBF reappeared in his navel.

He also noticed that the BBF was usually the color of the underwear below his waist, and not that of his upper body clothing. Perhaps, he suddenly thought, the BBF was being channeled by a “hair highway” (also known as a “snail trail”) running upward from his pubic hair to his belly button. This was a reasonable guess. Doug tested this hypothesis by shaving off part of his snail trail, in a horizontal band across his lower abdomen (not around his navel, as before). This effectively created a hair-free roadblock. Again, the BBF suddenly stopped. Inspired by Doug’s personal research, we set up a BBF survey on my webpage. Over the course of two months, 5,000 people responded (see results at Belly Button Lint: The Hole Story.

We found that the average generator of BBF was the slightly overweight, middle-aged male, though skinny young females could get it if they wore tight T-shirts.

Washing machines made a difference. Front loaders are more gentle on your clothes than top loaders—and sure enough, when people swapped their old top loaders for front loaders, the BBF was reduced or eliminated.

We examined samples from many people with the light microscope. Then, following the very important rule that anything, no matter how boring, looks interesting under the electron microscope, we used an electron microscope. BBF, we saw clearly, was made from fibers of clothing, dead skin cells and other skin debris.

When I was awarded the 2002 Ig Nobel Prize, the organizers showed so much respect for our work that I was flown to Harvard at my own expense. I welcome Dr. Steinhauser to this rich field, and wish him good fortune.


This article is republished with permission from the March-April 2009 issue of the Annals of Improbable Research. You can download or purchase back issues of the magazine, or subscribe to receive future issues. Or get a subscription for someone as a gift! Visit their website for more research that makes people LAUGH and then THINK.

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Dr Karl is the longest active presenter on Austrailian radio and has at least three active podcasts. Quite a hoot. Check him out.

Oh, I should also point out that he got an Ignoble Prize for this paper.
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