The control group
To control for nonspecific factors such as receiving sleep information and spending time with a researcher, the Control group was instructed to use Fitbit and Dreem without feedback about recorded sensor-based sleep throughout participation (e.g. sleep information was hidden on the Fitbit app). The Control group received a sleep education session conducted by the provisional psychologist (MAS) that covered: (1) psychoeducation about sleep (e.g. information about the function of sleep, sleep cycles, sleep stages, the homeostatic sleep drive, and circadian rhythms), and (2) sleep hygiene (e.g. healthy sleep habits regarding light, body temperature, physical activity, noise, food, caffeine, alcohol, and bedding).