Limited research has compared the circadian phase-shifting effects of bright light and exercise and additive effects of these stimuli. The aim of this study was to compare the phase-delaying effects of late night bright light, late night exercise, and late evening bright light followed by early morning exercise. In a within-subjects, counterbalanced design, 6 young adults completed each of three 2.5-day protocols. Participants followed a 3-h ultra-short sleep-wake cycle, involving wakefulness in dim light for 2h, followed by attempted sleep in darkness for 1 h, repeated throughout each protocol. On night 2 of each protocol, participants received either (1) bright light alone (5,000 lux) from 2210–2340 h, (2) treadmill exercise alone from 2210–2340 h, or (3) bright light (2210–2340 h) followed by exercise from 0410–0540 h. Urine was collected every 90 min. Shifts in the 6-sulphatoxymelatonin (aMT6s) cosine acrophase from baseline to post-treatment were compared between treatments. Analyses revealed a significant additive phase-delaying effect of bright light + exercise (80.8 ± 11.6 [SD] min) compared with exercise alone (47.3 ± 21.6 min), and a similar phase delay following bright light alone (56.6 ± 15.2 min) and exercise alone administered for the same duration and at the same time of night. Thus, the data suggest that late night bright light followed by early morning exercise can have an additive circadian phase-shifting effect.

The Writing Pal (W-Pal) is an intelligent tutoring system (ITS) designed to provide students with explicit writing strategy instruction and practice. W-Pal includes a suite of educational games developed to increase writing engagement and provide opportunities to practice writing strategies. In this study, first (L1) (n = 26) and second (L2) language (n = 16) students interacted with W-Pal over eight sessions. We collected students’ daily self- reports of engagement, motivation, and perceptions of performance, as well as their reported game attitudes (difficulty, helpfulness for learning, and enjoyment). Results indicated that, for all students, interactions with W-Pal led to increases in writing performance and more positive attitudes towards the system (engagement, motivation, and perceived performance). For L1 students, game difficulty was a significant predictor of boredom; however, for the L2 students, game enjoyment predicted both their motivation and perceived writing improvement. Notably, the L2 students’ game ratings accounted for more variance in these daily reports than did the ratings of L1 students. This study suggests that L1 and L2 students experience similar benefits offered by game-based strategy practice in an ITS. Further, the link between game attitudes and overall daily perceptions of training may be stronger for L2 students than L1 students.