Wearing an eye mask during overnight sleep improves episodic learning and alertness.

Ambient light can influence sleep structure and timing. We explored how wearing an eye mask to block light during overnight sleep impacts memory and alertness, changes that could benefit everyday tasks like studying or driving. In Experiment 1, ninety-four 18-35-year-olds wore an eye mask while they slept every night for a week and underwent a control condition in which light was not blocked for another week.