I have no trouble believing that they were on laptops. Working on a computer can be very engrossing, which is why working on a laptop should be banned on the flight deck.
This is distinct from the vigilance "games" I suggested, which would be specifically designed to heighten alertness without providing enough of a distraction to take attention durably away from the flying task. They would also be part of the aircraft systems, so they would alert pilots to any anomaly. It would just be a fancy version of the vigilance devices installed on just about all railway locomotives (and on a few aircraft).
I've always wondered how pilots can use iPhones and laptops even as the airline prohibits the use of electronic devices in the passenger cabin. Legally, if the airline hasn't tested these laptops and iPhones and found them to be free of interference with aircraft systems, using them on the flight deck is illegal in all phases of flight (in the United States), whether it's the pilots using them or not. Using a laptop on the flight deck thus puts the flight at risk, legally and possibly technically.