You just don’t.  Nobody does.

People like to speculate on the IQ of various celebrities. A popular one recently was Sarah Palin (“likely somewhere between 110 and 115“).  We may also have “learned” that Beyonce’s IQ is 124 (or is it 110?) And nobody can agree on Einstein’s putative IQ, except that it was somewhere between “only” 160 and 250 or more.

Online, I’ve seen the same group of nerds who enjoy self-diagnosing Asperger’s report their IQ scores as 180 or more (200 is a popular number).  There are two possible reasons a person might say this:

1. They took some fake test on the web.
2. They are making it up.

Whatever you happen to think about the intrinsic worth and predictive ability of psychometrics, real IQ tests are based on math.  The math expresses how many other people in their sample population achieved the same raw score that you did, by percentile.  Ideally, this sample group is a cross-section of the population that’s representative of the subject’s environment.

The most popular and reliable IQ test for adults is the Wechsler Adult Intelligence Scale, or WAIS, now in its fourth edition.  It was normalized against a sample of 2,200 adults.  Keep that number in mind.

This graph should be familiar to most people.  It’s a Gaussian curve, or normal distribution, of performance on a properly normalized IQ test like the WAIS.  Each color change represents one additional standard deviation from the mean.

It’s instructive to look really closely:

Each standard deviation in the WAIS is 15 IQ points further from the mean of 100. Because performance is normalized, only 0.27% of those taking the test are expected to fall outside of 3 standard deviations — in the WAIS this translates to scores above 145 and below 55.

If you take the WAIS and achieve a raw score comparable to only the top 0.135% of the original sample of 2,200, it means your performance is measured relative to 3 people.   Score 4 standard deviations above the mean (IQ >= 160) and you’re being compared to just 0.065 other geniuses.  In other words, it’s highly likely that no one in the WAIS sample scored as high as you.  Congratulations, you are “only” as smart as the lowest estimated IQ of Albert Einstein.

Above (or below) a certain threshold, IQ performance is simply noise.  If you extrapolated all the way to IQ 200 (and if you were that smart, you understand why you can’t), you’re scoring a whopping 6 standard deviations above the mean and will have to look elsewhere for your intellectual equals.  Since 99.9999998027% of a normally-distributed group falls within 6 standard deviations, the number of members of your uber-Mensa is 6.  In the entire world.

The fact is, most adults simply do not know their IQ.  Bright children are rarely tested as a matter of course (although some private schools do it).  In general, a child is given an IQ test when their school record is lacking, usually because there’s a disparity in expected versus actual performance.  IQ testing is a good way to reveal that an otherwise smart kid has a particular learning disability.  Psychologists typically do not care whether your IQ is 130 or 145.  They want to know if your non-verbal IQ is high but your reading score is below-average; you may have dyslexia and need special educational strategies to succeed.

But the real benefit of IQ is knowing that when someone quotes you a number and it’s greater than 145, it’s safe to assume they’re not as smart as you.

as my Ask Metafilter reading history:

• http://ask.metafilter.com/83669/Bad-pork-or-just-a-bad-smell
• http://ask.metafilter.com/83681/something-concerning-no-kids
• http://ask.metafilter.com/83689/Super-depressing-winter-murder-movie
• http://ask.metafilter.com/84685/I-do-declare-But-my-XML-doesnt
• http://ask.metafilter.com/83685/Does-this-guy-like-me-or-what
• http://ask.metafilter.com/84701/What-are-some-heavy-guitar-focused-triphop-albums-similar-to-Massive-Attacks-Mezzanine
• http://ask.metafilter.com/83656/allclad-or-bust
• http://ask.metafilter.com/83642/Im-a-bookish-introvert-stuck-in-the-advertising-industry-Help

The subway on the commute home was unusually subdued for a Friday evening. Maybe it was the crappy weather.

About halfway through the trip a perfectly normal-looking guy next to me said, clearly and distinctly, “Elephants.”

He got off at Harvard Square without saying another word.

A man and a woman, co-workers, in their twenties, are talking. The woman is pale, dark-haired, wire-framed glasses. She looks a little like me but younger and perkier. The man is lumpy, slouched, reeking of low expectations. He is clearly hitting on her.

“What are you listening to?” he asks. They are both wearing iPod headphones.

“Guster?” she says.

“Uh-huh.”

“What are you listening to?”

“The Swans.” He mumbles it.

“What?”

“The Swans?”

She’s nodding. “What are they like?”

“They’re kind of — goth?”

“Goth? I didn’t know that was–”

“Yeah.”

“I didn’t know what was a kind of music. I thought it was a fashion thing?”

“Yeah, I don’t really dress like that, I just — I like the music. I like all kinds of music,” he apologized.

“Yeah?”

The bus rumbles along and then arrives at our stop. He starts again. “So are you liking the job?”

“Yeah?” she says.

“It’s funny because of the orthography.”

I’m not from New England but I completely belong here. I was happy to be sent to a conference in San Francisco because it had been five years since I’d seen my SF friends, but California makes me uncomfortable. It’s too big, there aren’t enough subways and I’m suspicious of season-less climates. On the other hand, five years is too long to go between Mission burritos. My other culinary requirement when visiting the West Coast is usually sushi but this time I did not get the opportunity.

My corporate expense report will include both a $25 in-room breakfast and a $3 slice of pizza from the club district in SOMA. That seems about right.

I’ll be back again next month, incongruously enough, for O’Reilly’s Foo Camp. I’ll miss my dog and probably won’t get sushi then either.

On the way home I read David Crystal’s The Fight for English, a response to Eats, Shoots & Leaves by Lynne Truss (which I found tiresome). Although Crystal is explicitly not a language prescriptivist, he did remind me that I use too many commas. I hope you enjoy this post which contains fewer of them than I would have included otherwise.

It’s 64F now, 8pm and still sunny. I’m on the deck drinking a beer (pictured). It’s a Dogfish Head Indian Brown Ale. For dinner I had a regular burrito with black beans, rice, guacamole and hot salsa.

It’s quiet back here except for some squirrels rustling the trees, distant car traffic, and assorted birds. I have my laptop and a clear wireless signal. I had another perfect commute with my new bike, and when I got home I walked the dog for an hour and now she is very tired.

I got a notice in the mail that my jury duty service was cancelled. The sun is finally setting. It’s still warm.

This is galangal. I got it at Whole Foods, the first time I have seen it outside of an Asian grocery store. I bought it largely to take this picture.

That is all.

Even the coffee mugs in the office.

I don’t want one with a Bible quotation. I don’t want one that proclaims that I am “the world’s greatest” anything, especially “dad.” I don’t want one that has raised three-dimensional ceramic figures on it. I don’t want one that appears not to have been washed.

Some of them are too small, or too oddly shaped. The ceramic can’t be so thin that the mug is too hot nor so thick that drinking from it is uncomfortable. One mug is so cavernous that no matter how much coffee I put into it, it looks empty, and there’s so much surface area that the coffee cools too quickly.

I don’t like coffee mugs with gold laminate cursive writing.

There is a blue mug that I prefer but it is often dirty, and on my desk. It is good when I remember to bring my travel mug because that keeps the coffee warm while I do work or get on a conference call, and because it is normally filled with coffee from somewhere else, rather than from the office coffee maker which makes bad coffee.

In the Whole Foods produce section a man in his late 40′s is standing, inert, with an empty shopping cart. A woman of the same age, perhaps sensing prey, asks him if he needs any help finding something. “I’m just trying to remember a recipe,” he replies.

“Oh?” she says. “What kind of recipe?”

“It’s, uh, complicated,” he answers, in a tone that indicates he’s not interested in her cooking advice or anything else. Then, perhaps thinking he was too brusque, adds, “I’m a raw-foodist.”

“A raw-foodist.”

“Yes, I don’t eat cooked food.”

“People who eat raw food call themselves ‘raw-foodists.’” It’s not a question.

“Only to people who eat cooked food,” he replies sourly.

To me she says, “Welcome to Cambridge.” Then she pushes off into Seafood.