“Diane Sieber, an associate professor [at the University of Colorado at Boulder] identified 17 students in one of her classes who were using laptops most frequently. After the first test, she told them that they did 11 percent worse, on average, than their peers who did not have their faces in their computers as much. Lo and behold, the number of laptop-nosed students dropped to a half dozen, and the test scores of those who stopped using their computers during class went up.”

(Source)

As a task-performance study, it’s kind of lacking.  Hard to separate the effect of task feedback from the changes in laptop use.  But it’s still interesting for those of us who encourage note-taking and other course work using laptops.