the science of journaling
best time to journal, there is no rct
no head-to-head trial settles morning vs evening journaling. four indirect lines of evidence, chronobiology, sleep, worry, and one bedtime study, tilt one way.
The question keeps coming up. Morning or evening. Most pieces on the SERP answer it confidently, then fail to cite a single study.
The honest answer is that no head-to-head randomised controlled trial has ever directly compared morning journaling to evening journaling on a cognitive or wellbeing endpoint. None. The literature people gesture at is parallel evidence from four nearby fields, chronobiology, sleep-dependent memory consolidation, the worry-postponement tradition, and one polysomnography study at Baylor. Read together it tilts modestly toward evening.
This is a -pillar post about what the indirect evidence actually says: one polysomnography study at Baylor, the cortisol awakening response, sleep-dependent memory consolidation, and a 1983 worry-postponement protocol that anticipated the bedtime journal by forty years.
the question has no rct
Every other piece pretends the question is settled. It is not. Searches for best time to journal return listicles that recommend morning for clarity and evening for processing, with no citations and no acknowledgement that the comparison has never been run.
What exists is parallel evidence from four adjacent literatures. None of it crosses the road to ask the actual question. Reading them together still tilts the answer, but the tilt is a triangulation, not a verdict.
what scullin actually found
The closest thing to a direct empirical anchor is a 2018 polysomnography study at Baylor.[6] Fifty-seven young adults spent five minutes writing immediately before bed for one night. Half wrote a specific to-do list. Half wrote about tasks they had already completed. The to-do list group fell asleep faster.
references.
- 1.Borkovec, T.D. et al. (1983). Stimulus control applications to the treatment of worry. Behaviour Research and Therapy 21(3), 247-251.doi:10.1016/0005-7967(83)90206-1
- 2.Diekelmann, S. & Born, J. (2010). The memory function of sleep. Nature Reviews Neuroscience 11(2), 114-126.doi:10.1038/nrn2762
- 3.Harvey, A.G. & Farrell, C. (2003). The efficacy of a Pennebaker-like writing intervention for poor sleepers. Behavioral Sleep Medicine 1(2), 115-124.doi:10.1207/S15402010BSM0102_4
- 4.Payne, J.D. et al. (2008). Sleep preferentially enhances memory for emotional components of scenes. Psychological Science 19(8), 781-788.doi:10.1111/j.1467-9280.2008.02157.x
- 5.Pruessner, J.C. et al. (1997). Free cortisol levels after awakening: A reliable biological marker for the assessment of adrenocortical activity. Life Sciences 61(26), 2539-2549.doi:10.1016/S0024-3205(97)01008-4
- 6.Scullin, M.K. et al. (2018). The effects of bedtime writing on difficulty falling asleep: A polysomnographic study comparing to-do lists and completed activity lists. Journal of Experimental Psychology: General 147(1), 139–146.doi:10.1037/xge0000374