Concepts (page 23)

People are pulled by two needs at once, to belong and to stand out, and no single group size satisfies both. Marilynn Brewer's 1991 theory argues the relationship between a group's inclusiveness and…

Ostracism is being excluded or ignored, and it has one of the largest effect sizes anyone has measured in social psychology. Kipling Williams built the standard instrument, Cyberball, a three-player…

Outcome bias is judging the quality of a decision by how it turned out rather than by whether the process behind it was sound. A good decision that ends badly gets punished; a reckless one that ends…

Outsider art is art made by people outside the art world's training and institutions, historically including psychiatric patients, and valued on its own terms. Jean Dubuffet coined art brut in 1945…

Overconfidence is believing you are better, more able or more right than you actually are. The useful move is to stop treating it as one thing. Don Moore and Paul Healy split it in 2008 into three…

P-hacking is reworking an analysis until it crosses the conventional significance threshold. Drop the outliers, add a covariate, split by sex, collect twenty more participants and look again, try…

Papañca is the Buddhist account of thought multiplying on itself: what a person conceives they differentiate, and what they differentiate then multiplies back on them. It appears in the Madhupiṇḍika…

Peak attention is Tim Wu's name for the bounded window in which most of a country watched the same programme, and the same advertisements, at the same moment. The point of naming it a peak is that…

The peak-end rule is the claim that a finished experience is judged afterwards from two moments, the most intense one and the last one, rather than from the whole of it. The finding is Barbara…

Perceived physical activity is how active people believe they are, usually compared with others their age, measured separately from what they actually do. The two come apart, and the perception is…

Perception is an inference drawn from insufficient evidence, so it needs assumptions to close the gap. You did not choose them, you cannot inspect them, and their output arrives feeling like plain…

Personified emotion is the practice of addressing a feeling as a character rather than as a state. The feeling is given a name, a capital letter, a voice and something it wants, and then it is asked…