Light Timing Study

All participants will be assigned a 9-h sleep opportunity for the first week of the 2-week study. This will ensure that adolescents are not sleep restricted before living in the laboratory during the second week of the study. The 9-h sleep schedule will be individually timed from his/her averaged wake time (± 15 mins) before the study begins. Assigned bedtime will be 9 h before wake.

For all participants, their assigned baseline sleep/wake schedule will gradually shift earlier over 3 days in the laboratory to facilitate the phase advance shift of the circadian system.