Wisdom in Numbers

If you want to guess how many jelly beans are in a jar, you should ask your friends. Then average their answers. Because a group guess is often more accurate than that of any one individual. Just don't let them [blank] at each other's responses. Because a new study shows that social influence can sway people's estimates and render the crowd [blank] . The work appears in the Proceedings of the National Academy of Sciences . Crowd wisdom is actually a statistical phenomenon. Gather enough estimates and the wild guesses cancel each other out, bringing you closer to the answer. But psychology and statistics don't mix. And knowing what your peers think doesn't make you any smarter. European scientists asked volunteers to estimate statistics like the population density of Switzerland. Each person got five guesses. Some were shown their peers' answers and others weren't. Turns out that seeing others' estimates led to a lot of second- guessing. Which narrowed the range of the group's responses and pointed them in the wrong [blank] . Even worse, knowing that others said the same thing made everyone [blank] confident they were right. So there is wisdom in numbers-as long as those numbers keep quiet till they're counted.