A study was undertaken in 2013 with tenth-graders in Norway, where the students were divided into two groups. One group read two texts (1,400–2,000 words) in print and the other group read the same texts as PDFs on a computer screen. In the reading comprehension test that was administered, the students who read on paper scored significantly better than those who read the texts digitally. It was easier for those who read on paper to remember what they had read. Mangen et al. say that this is because paper gives spatio-temporal markers while you read. Touching paper and turning pages aids the memory, making it easier to remember where you read something. Having to scroll on the computer screen makes remembering more difficult.