Catching rays: Conditioning works underwater too



Q. What's the trick to safely hand-petting a stingray in the wild? –J. Cousteau

A. A trip to "Stingray City" of the Cayman Islands just might do it, where for 35 years fishing crews have gathered conch and cleaned them over a certain barrier reef, says David G. Myers in Psychology. Stingrays (shark relatives) in the surrounding bay gradually became accustomed to these treats and started hanging out in numbers. Scuba divers then began feeding the increasingly friendly rays by hand.

"Today, tourists can do the same, and can even pet the rays as they graze past them," Myers notes.

Psychologists know rewarded behavior is likely to recur. B.F. Skinner took this a step further with his "behavioral technology," teaching pigeons to walk a figure-8, play ping-pong, and keep missiles on course by pecking a target on a screen. Pigeons have also learned to discriminate categories such as people, flowers, cars and chairs. "With training, they have even been taught to discriminate between Bach's music and Stravinsky's," says Myers.

Q. How is flipping a coin a lot like tracking the volatile stock market? –W. Buffett

A. Imagine a series of 1000 coin tosses where Henry bets on heads every time, Tommy on tails, poses John Allen Paulos in A Mathematician Plays the Stock Market. The coin is "fair," so the two players are equally likely to be in the lead. But once one of them gets a bit of a lead, he's likely to stay in the lead over most of the 1000 flips. People find this hard to believe, says Paulos, because they believe in the "gambler's fallacy," thinking that the coin's deviations from a 50-50 split are "governed by a probabilistic rubber band: the greater the deviation, the greater the equalizing push toward an even split."

Not so! Even if Henry were way ahead, with 525 heads to Tommy's 475 tails, his lead would be as likely to grow as shrink. "Likewise, a stock that's fallen on a truly random trajectory is as likely to fall further as it is to rise," Paulos says.

True, in the long, long run the flips approach 50 percent-50 percent, but that's as a percentage, not actual numbers. Since lead switches are relatively rare, it wouldn't be surprising if either Tommy or Henry came to be known as a "winner" or "loser." Similarly, if one professional stock picker outperformed another by a margin of 525 to 475, he might wind up interviewed on Moneyline.

"Yet he might, like Henry or Tommy, owe his success to nothing more than getting 'stuck' by chance on the up side of a 50-50 split," Paulos says.

Also, of 1000 stocks, roughly 500 might be expected to outperform the market next year merely by chance, like a flipped coin. Of these 500, 250 will likely do well for a second year, 125 for a third, etc., and one will do well for 10 years in a row, by chance alone. Yet "some in the business media are likely to go gaga over the performance," according to Paulos.

Q. From Earth, the Moon is a charming sight, rising and setting through the course of the night while passing through its various phases over the lunar month. How does the Earth look from the vantage of the Moon? –N. Armstrong

A. The Moon has become entrained to the rotation of the Earth, spinning now at an exact rate that keeps the same face always toward our planet, engendering a "far side" (though not a "dark side"), says Paul Hewitt in Conceptual Physical Science. So the Earth from the Moon isn't seen to rise and set at all. Instead, it stays at the same point in the lunar sky all day but does pass through its own phases while hanging stationary there.

Q. It all began in 1913, its original name now reversed, so popular today it is recognized the world over, yet it took 10 years before a book of them was published and then only under a company pseudonym, though the book became a best-seller. What's a nine-letter word for the answer? –M. Farrar

A. The first crossword puzzle, by U.S. journalist Arthur Wynne, who called it a "word-cross," done for the 1913 Christmas edition of the New York Sunday newspaper World, recounts David Crystal in Language Play.

Send Strange questions to brothers Bill and Rich at