Notes

This book gives general information about an everyday habit. It isn't medical advice. The NHS guidance I mention is for England as I found it 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, 6, 8, 9, 10, 12, 14, 15, 18 and 21. The Tuesday meeting, Dan and Ellie, the lasagne, the keys in the other coat and everything else in the running example are invented.

Before you start. The signs of ADHD in adults and the advice to see a GP if they're affecting studies, work or relationships are from the NHS page "ADHD in adults". The page lists finding it hard to organise your time, being easily distracted or forgetful, finding it hard to finish tasks and losing things often among the inattentive signs, and says the symptoms usually start before the age of twelve.

Chapter 3. Buehler, Griffin and Ross, "Exploring the 'planning fallacy': why people underestimate their task completion times", Journal of Personality and Social Psychology 67, 1994, pages 366 to 381. The tasks were academic and everyday projects, not journeys. The summary reports that people focused on plan-based scenarios, that they underestimated their own completion times but not other people's, and that the bias disappeared when people were told to connect their predictions with past experience. Newby-Clark, Ross, Buehler, Koehler and Griffin, "People focus on optimistic scenarios and disregard pessimistic scenarios while predicting task completion times", Journal of Experimental Psychology, Applied, 6, 2000, pages 171 to 182. Five experiments. The application to the walk across the park is mine.

Chapter 4. Buehler, Griffin and Ross as above, for the finding that people attributed past prediction failures to external, transient and specific factors, and that observers made more use of past experience. Roy, Christenfeld and McKenzie, "Underestimating the duration of future events: memory incorrectly used or memory bias?", Psychological Bulletin 131, 2005, pages 738 to 756. A review paper. The authors present memory bias as an additional explanation and not a replacement for the planning fallacy account, and say the two aren't mutually exclusive.

Chapter 5. Block, Hancock and Zakay, "How cognitive load affects duration judgments: a meta-analytic review", Acta Psychologica 134, 2010, pages 330 to 343. One hundred and seventeen experiments. The shortening effect is for prospective judgements, where people know in advance that they'll be asked about time. For retrospective judgements the effect runs the other way. I've applied the prospective finding to the last thing on the grounds that a person watching the clock before leaving is in something like a prospective condition. That's my reading. Conte and Jacobs, "Validity evidence linking polychronicity and Big Five personality dimensions to absence, lateness, and supervisory performance ratings", Human Performance 16, 2003, pages 107 to 129. One hundred and eighty-one train operators. The correlation between polychronicity and lateness was 0.19, which is small. The explanation of why the last thing is attractive is mine.

Chapter 7. Buehler, Griffin and MacDonald, "The role of motivated reasoning in optimistic time predictions", Personality and Social Psychology Bulletin 23, 1997, pages 238 to 247. Two studies, one of tax filers and one in a laboratory. Halkjelsvik and Jørgensen, "From origami to software development: a review of studies on judgment-based predictions of performance time", Psychological Bulletin 138, 2012, pages 238 to 271. The review notes that underestimation was more often reported in engineering and management studies than in psychology studies, which is a limit on how general the planning fallacy is. What I say about the state you arrive in is my own observation.

Chapter 11. Conte and Jacobs as above. Conscientiousness, extraversion and neuroticism were associated with absence and not with lateness in that sample. Levine and Norenzayan, "The pace of life in 31 countries", Journal of Cross-Cultural Psychology 30, 1999, pages 178 to 205. Levine and Bartlett, "Pace of life, punctuality, and coronary heart disease in six countries", Journal of Cross-Cultural Psychology 15, 1984, pages 233 to 255. The questionnaire on lateness in the 1984 paper was conducted mostly in the United States, and I've used only the fact that it asked about perceptions of what counts as late. The argument that punctuality is a policy rather than a trait is mine.

Chapter 13. Kruger and Evans, "If you don't want to be late, enumerate: unpacking reduces the planning fallacy", Journal of Experimental Social Psychology 40, 2004, pages 586 to 598. I couldn't obtain a summary of this paper and have relied on its title, as the chapter says. Kahneman and Tversky, "Intuitive prediction: biases and corrective procedures", TIMS Studies in Management Science 12, 1979, pages 313 to 327. Citation only. The inside and outside views are described from general knowledge of that work.

Chapter 16. The two-week record, timing from door to seat, taking the longer figures and the sizes of the cushions are my suggestions and haven't been tested as a method. Newby-Clark and colleagues as above.

Chapter 17. Koole and van't Spijker, "Overcoming the planning fallacy through willpower: effects of implementation intentions on actual and predicted task-completion times", European Journal of Social Psychology 30, 2000, pages 873 to 888. One experiment, with an assignment to complete within a set period. The rest of the chapter's guidance is mine, including the ban on the last thing and the bowl for the keys.

Chapter 19. 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 and its parts haven't been tested together, and what I say to expect is my expectation and not a finding.

Chapter 20. The NHS page on ADHD in adults, as above. The advice to see a GP about a recent change in reliability that comes with low mood is general, and the NHS pages on depression describe the symptoms. Everything else in the chapter is my own suggestion.