Monday, June 4, 2012

Dirt Changes Psychology and Prevents Allergies

This weekend I spent some time volunteering on a farm. Today I’m scratched, sunburned and sore, but I have my theme for this week figured out. This week will be all about dirt. Where does it come from? Why do we hate it so much? Should we eat it? And are your attempts to clean yourself actually hurting you?

Call Mike Rowe, because things are about to get dirty.

Mike Rowe is a dry-witted hero of mine:


So what is dirt? 

Would you guess…

A)     Rocks
B)      Clay
C)      Dead things
D)     Water
E)      Air

In truth, it’s all of the above. Crunching the numbers, soil (“soil” sounds more scientific than “dirt”) is 25 percent air, 25 percent water, 45 percent minerals and 5 percent decayed matter. Air is important for the creatures and plants that live in soil, same as the water. And the minerals like clay and stones not only give soil its consistency, but also hold in moisture.

But wait, decayed matter? There are dead things in dirt? 

Yes. Dead plants, animals and insects on or in the ground contribute to soil. If a mouse were to have an aneurysm (I don’t like my hypothetical mice to suffer) and drop dead, within a day, flies and maggots would begin breaking it down. Fungus and worms would help send some of the nutrients from the dead mouse into the soil. Eventually, all that would be left are bones, which would be deconstructed by the weather, transformed into rocks and added to the soil too! 

Dirt never looked so adorable!
 The darker your soil, the more dead stuff is in it. More dead stuff means more nutrients to support plant life!


So what do we do with dirt? We get rid of it. Someone tracks dirt into our house, we sweep it away. If our hands get dirt on them, we wash them. We have an ingrained need to eliminate dirt in our lives.

But why? What has dirt ever done to us?

"All I am saaaaying is give peace a chaaaance..."
 The word “dirty,” which should literally mean “covered in, or having the quality of, dirt,” is used to mean disorganized, out of order, or unclean. Dirt isn’t our arch-enemy, so much as it is a metaphor for something else. Something we think is bad.

There’s a common phrase, “Cleanliness is next to godliness.” By that logic, being dirty has an absence of godliness. As a culture, we have connected cleanliness with morality and dirt with evil. Being dirty is bad because it means we don’t respect ourselves enough to be clean, or we aren’t “good” enough people to avoid messes.

And this way of thinking is messing with our heads.

Being “Dirty” Affects Our Perceptions

A team of psychologists at the University of Toronto did an experiment: have people sit down, read a series of social issues and then judge them from 1, completely moral, to 11, absolutely immoral. The issues included smoking, pornography, drug use, etc. 

Simple, right? Well, the psychologists added a twist: half of the volunteers washed their hands before the test and the other half did not. They found that the people who were “clean” judged the issues harsher than the “dirty” people.

The experiment only included 58 people. Hardly enough participants for a good study… So they upped the ante. After the initial experiment, they took 323 people in for a follow-up experiment and added 10 more social issues. And the findings were the same – the “clean” group judged harsher than the “dirty” group.

Chen-bo Zhong, a psychologist on the team, said, “[unconscious] metaphorical thinking confuses physical purity with moral purity.” In other words, this idea of dirt being “bad” goes so deep that we aren’t even aware that we’re making that connection anymore.

“Clean freak” is starting to take on a whole new meaning…

For hand washing... or brain washing?

Over-Cleaning Can Cause Allergies

It’s not just your mind that’s affected by our culture’s obsession with being clean, but your health. In the 1990s, Dr. Erika Von Mutius ran a study that found that children in poorer, dirtier cities developed fewer cases of allergies than children in wealthy, well-developed areas. Her hypothesis, now known as the Hygiene Hypothesis, is that the immune system develops when a child is very young. If a child is exposed to good bacteria (probiotics,) animals, diverse plant life, and yes, dirt, their body learns how to deal with these things better than a child who grows up in a sterile environment.

Think of the immune system as a prize fighter. The more practice it gets with punching bags and other non-threatening objects (allergens at an early age,) the more prepared it is to deal with real fighting later. If the immune system isn't allowed to train, it goes into the ring without knowing how to throw a good punch and ends up slapping wildly at everything. Instead of attacking only what is bad for us, the immune system gets caught up on allergens, harmless particles, because it wasn't trained. 

"Let me at 'im, coach! Pollen ain't that tough!"
To be fair, this is just a hypothesis; there is a lot of debate over whether or not it is credible. One video interview I watched on YouTube had a doctor saying that there was no evidence to support the Hygiene Hypothesis and that sanitation techniques had nothing to do with the development of allergies. Of course, that video was hosted by Lysol

But another study I read, as well as the following video, support the Hygiene Hypothesis.

So, does keeping your kid clean all the time promote allergies? The jury is out. But with more evidence stacking up, I'm pretty sure I'll be letting my children roll in the mud. And I'll be rolling with them.

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