Notes

This book gives general information about an everyday habit. It isn't relationship counselling or medical advice, and it's no substitute for a counsellor or a GP who knows you both. The services I mention are for the UK as I found them in September 2026.

I've kept sources out of the chapters where I could so they read easily. Here they are by chapter, with the limits I'm aware of. Unless I say otherwise, I read the published summary of each paper and not the full text. I checked each paper for a retraction or correction notice in September 2026 and found none. Where a chapter isn't listed, it rests on my own reasoning. That includes chapters 1, 2, 8, 9, 10, 11, 12 apart from Killgore, 13, 17, 20, 21, 22, 25 and 26. The dishwasher, the sofa at one, the alarm at half past six and the kitchen table at eight are invented.

Before you start. The helpline number is from the NHS pages on getting help for domestic abuse, and the two-week guide for low mood from the NHS pages on depression, both as verified for earlier books in this series.

Chapter 3. Golder and Macy, "Diurnal and seasonal mood vary with work, sleep, and daylength across diverse cultures", Science 333, 2011, pages 1878 to 1881. Social media data, which has limits the chapter names. What the old rule assumes is my reading.

Chapter 4. Walker and van der Helm, "Overnight therapy? The role of sleep in emotional brain processing", Psychological Bulletin 135, 2009, pages 731 to 748. A model built from a review, and the chapter keeps the question mark. The comparison of the two mornings is my observation.

Chapter 5. Vandekerckhove and Cluydts, "The emotional brain and sleep: an intimate relationship", Sleep Medicine Reviews 14, 2010, pages 219 to 226. Kahn, Sheppes and Sadeh, "Sleep and emotions: bidirectional links and underlying mechanisms", International Journal of Psychophysiology 89, 2013, pages 218 to 228. Both reviews. The earlier book on the night mind is Nothing gets solved at three in the morning. The claim that the truce is what lets you sleep is mine.

Chapter 6. Anderson and Platten, "Sleep deprivation lowers inhibition and enhances impulsivity to negative stimuli", Behavioural Brain Research 217, 2011, pages 463 to 466. A laboratory study after one full night without sleep, which the chapter extends to a late evening with the caution stated. Killgore, "Effects of sleep deprivation on cognition", Progress in Brain Research 185, 2010, pages 105 to 129. Yoo, Gujar, Hu, Jolesz and Walker, "The human emotional brain without sleep: a prefrontal amygdala disconnect", Current Biology 17, 2007, pages R877 to R878, for which no summary was available and only the title is used. The earlier book on anger is Still true in twenty minutes.

Chapter 7. The earlier book on staying up late is You were tired at ten.

Chapter 14. Hasler and Troxel, "Couples' nighttime sleep efficiency and concordance: evidence for bidirectional associations with daytime relationship functioning", Psychosomatic Medicine 72, 2010, pages 794 to 801. Twenty-nine couples for seven days, which the chapter says is small, and the gender-specific findings are reported as the study reports them. The earlier book on raising difficult things is Say it this week.

Chapter 15. Walker and van der Helm as above. Finkel, Slotter, Luchies, Walton and Gross, "A brief intervention to promote conflict reappraisal preserves marital quality over time", Psychological Science 24, 2013, pages 1595 to 1601, as verified for the earlier book You don't have to win this one, which calls the neutral view the third seat. Killgore as above.

Chapter 16. Christensen and Heavey, "Gender and social structure in the demand/withdraw pattern of marital conflict", Journal of Personality and Social Psychology 59, 1990, pages 73 to 81, as verified for the earlier book You don't have to win this one. The distinction between a truce and a withdrawal is mine.

Chapter 18. Hasler and Troxel, Anderson and Platten, and Finkel and colleagues as above. The NHS insomnia page for seven to nine hours, as verified for an earlier book. The rest is mine.

Chapter 19. Anderson and Platten, and Walker and van der Helm, as above. The comparison of the two arguments is mine.

Chapter 23. Gollwitzer and Sheeran, "Implementation intentions and goal achievement: a meta-analysis of effects and processes", Advances in Experimental Social Psychology 38, 2006, pages 69 to 119. The rule hasn't been tested as a package, and what I say to expect is my expectation and not a finding.

Chapter 24. The helpline and the NHS pages as above. Relate is named as the best-known UK provider of couples counselling, and no claim is made about its effectiveness. The earlier book on raising difficult things as above.