Students who use laptops in class are likely different from those who don’t. They may be more easily distracted or less interested in the course material. Alternatively, they may be the most serious (or wealthiest) students who have invested in technology to support their learning.
Randomization assures us that, on average, the students using electronics in a study are comparable at baseline to those who do not. That means that any comparison we make of students at the end of the study is caused by the “treatment,” which in this case is laptop use.
In a series of laboratory experiments, researchers at Princeton and the University of California, Los Angeles, had students watch a lecture, randomly assigning them either laptops or pen and paper for their note-taking. Understanding of the lecture, measured by a standardized test, was substantially worse for those who had used laptops.
Learning researchers hypothesize that, because students can type faster than they can write, a lecturer’s words flow straight from the students’ ears through their typing fingers, without stopping in the brain for substantive processing. Students writing by hand, by contrast, have to process and condense the material if their pens are to keep up with the lecture. Indeed, in this experiment, the notes of the laptop users more closely resembled transcripts than summaries of the lectures.
Taking notes can serve two learning functions: the physical storage of content (ideally, for later review) and the cognitive encoding of that content. These lab experiments suggest that laptops improve storage, but undermine encoding. On net, those who use laptops do worse, with any benefit of better storage swamped by worse encoding.
We could try to teach students to use their laptops better, nudging them to think about the material as they type. The researchers tried this in a second experiment, advising the laptop users that summarizing and condensing leads to more learning than transcription. This instruction had no effect on the results.
Students using laptops can also distract their classmates from their learning, another lab experiment suggests. Researchers at York and McMaster recruited students to watch a lecture and then tested their comprehension. Some students were randomly assigned to do some short tasks on their laptops during the lecture (e.g., look up movie times). Others were allowed to focus on the lecture. All seats were randomly assigned.
As expected, the multitasking students learned less than those focused on the lecture, scoring about 11 percent lower on a test. What is more surprising: the learning of students near the multitaskers also suffered. Students who could see the screen of a multitasker’s laptop (but were not multitasking themselves) scored 17 percent lower on comprehension than those who had no distracting view. It’s hard to stay focused when a field of laptops open to Facebook, Snapchat, and email lies between you and the lecturer.