Researchers at Florida State University have found that fidgeting may actually help children with ADHD to focus on challenging tasks.

Their study focused on working memory, the ability to "[update] or mentally [rearrange] information" that is often "difficult" for children with ADHD. The twenty-five children in this study had to remember and reorder information, including series of letters and numbers in one version and the colors of a line of dots in another, with progressively complex demands. The more challenging the information, the more the children fidgeted, and the more they fidgeted, the more they remembered.

"It's another piece of evidence that the hyperactive behavior more and more seems to be purposeful for them," said Michael Kofler, the author of the study. "This movement is how they get the juices flowing."

Read more about the study in the original article.