The authors, from Princeton University and UCLA, performed three studies on college students. They found that even if multitasking and distractions were eliminated, students who took notes on laptops performed worse on conceptual questions than students who took notes longhand.
Previous research has shown that note taking enhances learning by both providing external storage of information for later review and encoding, that is, processing information and reframing it in ones own words.
Although significantly more notes were taken by laptop users, they tended to be more like transcriptionists instead of thinking about and summarizing what they heard.
When tested on standardized lecture material, both groups did equally well on factual questions, but those who used longhand for note taking fared significantly better on questions dealing with concepts.
Even when students using laptops were instructed not to transcribe lectures verbatim, they were unable to do so.
Subjects were tested with and without studying their notes. Without studying before a test, scores did not differ between the two groups, but when studying was permitted, those who took longhand notes again performed better.
From the discussion section of the paper: Although more notes are beneficial, at least to a point, if the notes are taken indiscriminately or by mindlessly transcribing content, as is more likely the case on a laptop than when notes are taken longhand, the benefit disappears. [That run-on sentence was probably typed on a laptop.]
The authors concluded that laptops in classrooms may be doing more harm than good.
This dovetails nicely with my previous post on live-tweeting of conferences and lectures. People who live tweet claim the tweets can serve as notes. I doubt that. The live tweeters are deluding themselves. They are simply doing play by play of a session and are not likely to retain the information.
From a Guardian essay on this topic: A linguistic professor "conducted a survey of reading preferences among over 300 university students across the US, Japan, Slovakia and Germany. When given a choice between media ranging from printouts to smartphones, laptops, e-readers and desktops, 92% of respondents replied that it was hard copy that best allowed them to concentrate."
According to an article in the Wall Street Journal, smart pens can record what is written in longhand and convert it to digital text albeit with some difficulties and inaccuracies. Using a stylus on a tablet computer can also be done, but not as quickly as writing with a dumb pen on paper.
Like reading a real book instead of a digital book, taking notes may be another area in which the gadgets lose.