Concepts (page 79)

  • The Ovsiankina Effect

    The Ovsiankina effect is the tendency to go back to a task that was interrupted and finish it. It is named after Maria Ovsiankina, who reported it in 1928. A 2025 meta-analysis by Romain Ghibellini…

  • The Paceometer Effect

    Drivers badly misjudge how much time they will save by going faster, because a speedometer shows distance per unit of time while the quantity a driver is actually deciding about is time per unit of…

  • The Pain of Paying

    The pain of paying is the immediate discomfort of parting with money, which can spoil the pleasure of what is bought. Drazen Prelec and George Loewenstein set out the idea in 1998. The theory is…

  • The Parable of the 38 Witnesses

    The story is that 38 neighbours watched Kitty Genovese murdered in Queens in 1964 and did nothing. It illustrated the bystander effect in textbooks for forty years. Rachel Manning, Mark Levine and…

  • The Photo-Impairment Effect

    The photo-impairment effect is Linda Henkel's 2014 finding that people remember less visual detail about an object they photographed than about one they only looked at. It has replicated several…

  • The Planning Fallacy

    The planning fallacy is the habit of producing plans and forecasts that sit unrealistically close to a best-case scenario, when statistics on comparable projects were available and were not…

  • The Pleasure-Pain Balance

    The pleasure-pain balance is Anna Lembke's central device in Dopamine Nation and the spine of the whole book. Pleasure and pain are drawn as a seesaw: tip it one way and the brain, which wants the…

  • The Population to Individual Gap

    The population to individual gap is the distance between a result that holds on average across many people and a claim about one named person. Group averages are computed over distributions that…

  • The Portion Size Effect

    Give people a larger serving and they tend to eat more of it, by a modest but reliable amount, and they do not report feeling any fuller for having done so. The size of what is put in front of a…

  • The Practitioner Experiment

    The practitioner experiment is a source class the vault names for original experimental data generated by an author or the author's consultancy, reported in the body text, and existing nowhere else…

  • The Practitioner Memoir

    The practitioner memoir is a genre the vault treats as a source class: a book in which someone who did the job turns their career into a framework, and the evidence for the framework is the author's…

  • The Pratfall Effect

    The pratfall effect is the idea that a competent person, or brand, becomes more likeable after a small blunder. The 1966 study behind it shows less than the folklore: the boost for the competent…