The Wall Street Journal reports on how two research subjects pass the time—and work to stay awake—during a Penn study on sleep deprivation.

“We have to add sleep to this crazy world,” says David F. Dinges, a professor in the department of psychiatry and the 66-year-old director of the Penn lab. “And if we can’t stop short sleeping, the question is: How do we optimize the ability to tolerate [sleep loss], what are the effects of this and how do we reverse it, stop it and alter it?”

On a recent Monday, Ms. Burton was one of three subjects living in the Penn sleep lab, a small, windowless space with linoleum floors and dim fluorescent lighting. The participants—who are paid about $2,000—won’t leave at all during the 14-day study. They can’t exercise, use their phones or access the Internet. (Light and physical activity can affect sleep, mood and test performance. So can an argument with a significant other.)