This study measured the effect of using an electronic device for a non-academic purpose during class on subsequent exam performance. It was found that dividing attention between an electronic device and the classroom lecture did not reduce comprehension of the lecture, as measured by within-class quiz questions. Instead, divided attention reduced long-term retention of the classroom lecture, which impaired subsequent unit exam and final exam performance. Students self-reported whether they had used an electronic device in each class. Exam performance was significantly worse than the no-device control condition both for students who did and did not use electronic devices during that class.
Glass, A. L., & Kang, M. (2018). Dividing attention in the classroom reduces exam performance. Educational Psychology. https://dx.doi.org/10.1080/01443410.2018.1489046