First, I gave the students a poll about their preferences. Then I gave the students a short article to read in class. Half the class were directed to the article on their laptops. The other half were told to shut down their electronics and given a printout of the article. Then I gave them all a brief quiz on the details of the article. The quiz was checked for right/wrong answers, but not graded. They thought it was a fun experiment.
And yes, the "print" readers did the best!
Students all read the first article. The others were each assigned to 2-3 students.