Teachers

In the book we discuss how to combat mistaken perceptions, such as people’s inflated sense of the danger of shark attacks — the attacks are so rare as to be mathematically soothing, and in fact the danger of shark attacks is dwarfed by the danger of deer attacks (aka those little furries who dart mindlessly in front of your car just at the moment when braking would be pointless).

Here’s another approach to the same topic: Turns out SAND ATTACKS are more dangerous than sharks: (Thanks to Hashim for the pointer)

http://www.cnn.com/2007/HEALTH/06/20/sand.deaths.ap/index.html

Update: The link above no longer works but here is a link to CBS article on the same topic.

From a story in the Eugene, OR Register-Guard (thanks to Len H for the link) (Update: here is a link to the same story from CBS):

Kyleray Katherman, 13, thought something was funny about the water coming from the drinking fountains at his school. So, being far more intelligent and resourceful than I was at 13, he conducted an experiment. He used a Q-tip to swab the spigots of four different drinking fountains (and also a toilet for good measure). Then he took the samples back to the lab and tested them for bacteria. (Apparently junior high is a good bit more like CSI than in my day.) Result: The toilet water was Evian compared with the drinking-fountain water.

Then, in a masterstroke of stickiness, Katherman presented his analysis of the 5 sources of water to his classmates, and without telling them where each sample came from, he asked them which source they’d prefer to drink from.

They chose the toilet water, of course. And imagine the looks on their faces when he let them know. (For that matter, imagine the look on *his* face when his punchline worked as intended.)

Think about how much more powerful it was for him to structure the presentation this way, getting people to commit to a preference for toilet water, rather than launching into his presentation with a typical opener: “Based on my analysis of the drinking water in this school, there was a significantly higher level of bacteria in the drinking fountains than in the toilets.”

It’s a surprising fact, a fact that warns of overpopulation and a world teetering on the edge of exhaustion: The number of people alive today outnumber all those who have ever lived.

And it’s dead wrong. Ciara Curtin in the Scientific American does a nice dismantling of this urban legend.

Why did this falsehood spread? It has the snap of unexpectedness that you find in a lot of scientific-ish urban legends. (You only use 10% of your brain!) It balances that surprise factor by tapping into our sense of concern and anxiety for the world. (Have we pushed the planet too far?)

The surprise value and emotional resonance are garden-variety strengths of urban legends. This legend has another tricky feature, though. It appeals to our intuition about exponential numbers — for instance, if you take a sequence like 3^2, 3^3, 3^4, …, each successive number is greater than the sum of all the numbers before it in the sequence. If we have the (mistaken) sense that the earth’s population works like this sequence, the urban legend would seem quite reasonable. (It might even, perversely, make us feel smarter to believe it than not to believe it, since in tracing the exponential logic in our heads, we might flatter ourselves to believe we had solved the logic puzzle that explained a surprising “finding.”)

The answer to this question, and more, at the Powell’s site where we’re guest-blogging this week.

I was pleased to be able to include this sentence in today’s entry: “A study on toads found the creatures mostly used their right legs when removing a plastic balloon that researchers had wrapped around their heads.”

Clarke Ching sent over a link to the Penn & Teller show Bullshit! The Numbers. (30-min Google video) There’s some great stuff here — some cockroach wrangling, some binge-eating, some live street cons, some cursing at Frank Luntz, and a hidden-camera expose of a timeshare salesman. The theme is the way numbers, especially big ones, tend to fuzz our judgment.

Favorite quote: “Your odds of being killed by tap water in the next year are 20 times greater than your odds of winning a multi-state lottery jackpot.” Erp.