STRANGE BUT TRUE- Impish: Try not to think about it


Q. Has the "Imp" been whispering perverse thoughts in your ear lately, such as "Go ahead and jump" when you're on a high bluff, or "Confess" when you'd rather keep something to yourself? Just who is the Imp? –C. Stuart

A. In Edgar Allen Poe's "The Imp of the Perverse," the protagonist carries out the perfect murder and enjoys his ill-gotten gains, constantly reassuring himself, "I am safe..." But one day his mantra changes to "I am safe, yes, if I be not fool enough to confess." With that thought, he comes undone, says UVA's Jonathan Haidt in The Happiness Hypothesis. Now the more the murderer tries to suppress the thought of confessing, the more insistent it becomes until he panics and blacks out. When he comes to, he learns he has made a full confession.

     Now researcher Dan Wegner has brought the Imp– "the divided mind," really– into the lab, asking subjects to try hard not to think about something, such as a white bear, food, etc. It can't be done, of course, and soon the thought comes flooding in, with the automatic and controlled mental processes going at cross-purposes, says Haidt.  Automatic processes generate thousands of thoughts and images every day, some of them scary or shameful shockers that we try to suppress or deny.  "And once we have tried and failed to suppress them, they can become the sort of obsessive thoughts that make us believe in Freudian notions of a dark and evil unconscious mind," he concludes.

Q. A wealthy mathematician, on a crusade to stamp out innumeracy, challenges you with this problem:  She's the mother of two, with at least one boy.  Now for $1000, what's the likelihood the other child is also a boy? –L. Cohen

A. Did you say 1 in 2? Sure seems the chance of any child being a boy should be like a coin flip, but the woman has a trick up her sleeve. First, picture the kid possibilities:

     1) Older child a boy, younger a boy:  B-B

     2) Older child a boy, younger a girl:  B-G

     3) Older child a girl, younger a boy:  G-B 

     The fourth possibility of G-G, she has ruled out.

     Of the three possibilities, all equally likely, in only 1 out of 3 are both children boys, which is what she was asking. So if you said 1 in 3, you're already part of the crusade and a little richer for it. Note that if she had said her older child is a boy, then 1 in 2– as most people guess– would have been correct. (Discover magazine.)

Q. Insomnia is common enough. Have you ever lost sleep over "pseudoinsomnia"? L. Robbins

A. Some people will think they're not getting a good night's rest, but sleep lab tests show they're sleeping just fine. One hypothesis, reports Josh Gerow in Psychology: An Introduction, is that such sleepers dream of lying awake and trying to get to sleep, and in the morning remember these dreams and conclude it was a fretful, sleepless night. Usually just finding out that they're sleeping normally is enough to cure their pseudoinsomnia.

Q. How muscular must a basketball player be to shatter a backboard, glass flying everywhere? –S. O'Neal

A. It's not a matter of how much force but rather how it's applied, says John J. Fontanella in The Physics of Basketball. This first happened in pro ball at the Boston Arena in 1946, during warmups. The shooter was Celtic Chuck Connors, later star of The Rifleman TV series, whose two-handed set shot from 15-20 feet slammed into the rim. It turned out a piece of protective rubber had not been installed behind the basket, which exerted an edge force that shattered the backboard.

     Some rear car windows are made from the same material, says Fontanella, who recalls seeing a replacement window "spontaneously" disintegrate at an emissions testing facility. Both are of tempered or toughened glass, 4-5 times normal strength but weaker at the edge. One treatment requires heating to 1200 degrees F (650 C), then rapid cooling. The outer surface ends up in compression and the inner in tension, a delicate balance of forces that when upset will shatter the glass. So it's more the stored energy in the backboard and only incidentally the player that unlooses the spectacle. 

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