Thursday, March 29, 2012


"Science teaches us..."

False Taste Bud Map
Science has, for modern man, often replaced the voice of the prophet. Instead of a bearded man in a robe giving up the words of God, the man in a lab coat gives us the voice of science, and people presume it isn't just accurate but normative for their lives: the recommendation of 4 out of 5 dentists is what we ought to do, not just their opinion.

And typically, scientists tend to get things pretty right, when they focus on their job at hand. When they begin to speculate, predict, and guess, well they're no better than you or I on most topics. And when they pontificate on something wholly unrelated to their field of expertise, they're often worse.

The problem with science as the voice of God is that it keeps changing. Scientists once were certain that health problems were caused by imbalances of "humors" in the body, carried through the blood, and by bringing these humors back into proper balance, one would be healthy once more. Scientists once thought that the sky was a dome with stars affixed to it. Science can be wrong, and usually is a little bit wrong even at its best, and later work reveals this.

Its not that you cannot effectively rely on most things scientists say, its that you should take what they say for what it is: the best conclusion based on the best information we have, but subject to later change and clarification.

Here are a few examples of "settled" science people took as the word of God that ended up not being exactly true.

Cracking your knuckles causes arthritis. Yes, this seems like it has some validity and it sounds scientific, but it isn't true. A medical study published in the Journal of Manipulative and Physiological Therapeutics examined 300 knuckle crackers and found no increased risk of arthritis. they did find some correlation between cracking knuckles and weaker grip but nothing

Your tongue has four different zones for taste - sweet, salty, bitter, and sour. Except, it doesn't. First off, there's a fifth taste type (savory, sort of the flavor of meat), which the Japanese identified. And it turns out your tongue doesn't have special zones. It has some zones that react more strongly to some tastes (sour, for example) but the top of your entire tongue can pick up any kind of flavor or taste. The problem is a Harvard professor named Boring mistranslated a German study called Zur Psychophysik des Geschmackssinnes and came up with the now-famous tongue chart (pictured above). Its pretty easy to test, with any food you have handy.

You have (insert number) pounds of undigested meat in your intestines, which stays for years. This one is pretty easy to debunk: your stomach isn't a refrigerator. This one was promoted by one of those activist labs trying to get people to not eat red meat. Every so often these food myths show up, backed by some questionable science, and always promoted by a vegetarian operation. Or a "high colonic" business.

Greasy food and chocolate causes acne. No study shows that this is true, but lack of proper skin care and eating a lousy diet will cause your body to react poorly. Acne is primarily caused by hormones and not cleaning your pores properly. Soap and water will do fine for most people, and a good healthy diet will do you wonders, but these items aren't the cause.

Swallowed gum stays in your stomach for years. Stomach acid can dissolve metal let alone some cellolostic material like gum. And in any case, your body flushes materials out, so even though some parts of the gum are indigestible, they don't stick around.

We only use 10% of our brains. MRI scans show that we use all of our brains, just not all at once. We have lots of muscles on our body, but never once do we use all of them at the same time. Its the same way with your brain, and a lot of it is used for backup. Incidentally, recent studies show that your brain isn't the only part of your body used for thought and neural activity, its just one of the primary ones. Sorry, I know this sounds like a shortcut to superhero powers and its the basis of a lot of stories, but its just false.

Inoculations cause children to develop autism. This one is a horrible, evil myth created by a shoddy study done by one lab. it is not just false, but perniciously so, because it is causing once-obliterated diseases like smallpox and polio to creep back up on us. I cannot believe anyone would be so wicked as to promote this. Don't be ignorant and help spread the evil.

Women are born with all the eggs they'll ever have, in their ovaries. Not true; as it turns out the female body produces more eggs as time goes on. A study found out that the ovaries of a healthy adult woman have the stem cells needed to produce more eggs and can continue to do so until menopause shuts the system down.

Your fingernails and hair grow after death. This one is just not true. Once you die, your metabolic processes come to a halt. It can take a day or so for the very tiny cellular level things to die, but you stop growing. What does happen, however, is that your scalp and skin recede, causing the appearance of growth.

Reading in dim light hurts your eyes. Aside from some temporary eye strain, no study has shown any damage from low light reading. As you get older, however, you'll find that you need more and more light to properly read because your eyes get poorer (and most people start developing cataracts at some point).

Shaved hair grows back faster, coarser and darker. I'll let Robert Roy Britt at Live Science handle this one:
A 1928 clinical trial compared hair growth in shaved patches to growth in non-shaved patches. The hair which replaced the shaved hair was no darker or thicker, and did not grow in faster. More recent studies have confirmed that one. Here's the deal: When hair first comes in after being shaved, it grows with a blunt edge on top, Carroll and Vreeman explain. Over time, the blunt edge gets worn so it may seem thicker than it actually is. Hair that's just emerging can be darker too, because it hasn't been bleached by the sun.

Next time you hear someone say "settled science" or act as if a scientist's declaration is the voice of God on high, remember this kind of thing. Science is a discipline or a job like any other. It has good people working in it and bad. Politics, agendas, and personal biases take place in science just like any other field. A scientist doesn't know any more about reality than a logger or a jeweler.

*This is part of the Common Knowledge series.

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