Use of digital tools can affect our understanding of what we read. Researchers Geoff Kaufman and Mary Flanagan found that those who read an article on a computer answered concrete questions better while those who read it from a printout were better able to answer abstract questions. More of those who studied a printed spreadsheet could analyze the statistics to make a decision than those who used the laptop. By specifically adding a task to a written document it was also possible to encourage more abstract or critical thinking in readers. Kaufman said "If I catch myself reading a journal article in a PDF, and I start to get stuck on the details of the methodology, I’ll just go ahead and print it out.” The authors presented at the recent ACM Conference on Human Factors in Computing Systems.