The effort of communicating to someone else forces you to pay more attention and learn more. You can see this audience effect even in small children.
In one of my favorite experiments, a group of Vanderbilt University researchers in 2008 published a study in which several dozen 4- and 5-year-olds were shown patterns of colored bugs and asked to predict which would be next in the sequence. In one group, the children simply repeated the puzzle answers into a tape recorder.
In a second group, they were asked to record an explanation of how they were solving each puzzle.
And in the third group, the kids had an audience: They had to explain their reasoning to their mothers, who sat near them, listening but not offering any help. Then each group was given patterns that were more complicated and harder to predict.
The children who didn’t explain their thinking performed worst. The ones who recorded their explanations did better—the mere act of articulating their thinking process aloud seemed to help them identify the patterns more clearly. But the ones who were talking to a meaningful audience—Mom—did best of all. When presented with the more complicated puzzles, on average they solved more than the kids who’d explained to themselves and about twice as many as the ones who’d simply repeated their answers.
Researchers have found similar effects with adolescents and adults.
Interestingly, the audience effect doesn’t necessarily require a big audience. This seems particularly true online.
Clive Thompson, Smarter Than you Think