ROCK BREAKS SCISSORS

An ingenious guide to outsmarting others by predicting their choices when they are trying to be unpredictable.

Being predictable is difficult, writes business and science writer Poundstone (Are You Smart Enough to Work at Google?, 2012, etc.). When taking tests in which they are asked to write a series of random numbers, almost everyone avoids repeats such as 4444, but true randomness requires them. The authors of these tests fall into this trap, so if a correct answer in a true-false test is true, the following is more likely to be false and vice versa. If doubt remains, guess true, since 56 percent of true-false answers are true. Test authors must invent many wrong answers for every right one, and it’s tempting to use shortcuts. The easiest is to insert “never,” “always,” “all” or “none,” into a reasonable statement. Never choose these. On the other hand, if one answer is “all of the above” or “none of the above,” the test author must carefully write the other answers around them, so why waste all that work? These are correct an astonishing 52 percent of the time. Many genuine insights on gambling, betting pools and the stock market have limited appeal, but the string of surprises continues. Thus, hot streaks (consecutive wins in any sport and other examples) occur as often as they do in roulette. In other words, they’re purely random. “All of this book’s applications are founded on one simple idea,” writes the author. “When people make arbitrary, random, or strategic choices, they fall into unconscious patterns that you can predict.”

Malcolm Gladwell’s Outliers (2008) and Nassim Nicholas Taleb’s The Black Swan (2007) fascinated readers with evidence that reality regularly contradicts common sense. Poundstone delivers modestly useful advice for taking advantage of this, but mostly his book is another delightful addition to the everything-you-thought-you-knew-is-wrong genre.