How to tap the wisdom of the crowd in your head

Researchers conducted a test to find out if individuals can make better estimates of historical dates if they make two guesses and average them. It turns out they can!
Herzog and Hertwig used the insights of the “wisdom of crowd” perspective to make one head nearly as good as two. After participants made their first guesses at the dates of historical events, they then made a second estimate using one of two methods. In one condition, participants simply gave a second estimate. This condition did little to increase either knowledge or diversity.

In the second condition, participants were given detailed directions for making their follow-up guess: “First, assume that your first estimate is off the mark. Second, think about a few reasons why that could be. Which assumptions and considerations could have been wrong? Third, what do these new considerations imply?... Fourth, based on this new perspective, make a second, alternative estimate.” When the participants used the more involved method, the average was significantly more accurate than the first estimate. The “crowd within” achieved about half the accuracy gains that would have been achieved by averaging with a second person.

How to tap the wisdom of the crowd in your head