Warning: Surfing the internet in class is now linked to poorer test scores, even among the most intelligent and motivated of students.

New study shows that splitting attention between lecture and cellphone or laptop use hinders long-term retention, and those in class suffer from others' use of devices.

Outside of these areas, however, the benefits of 1:1 laptop availability are mixed. Different studies have found changes in math and science test performance that were inconsistent. In general ...