effect

• Anchoringtype: effect · evidence: strong

  A number you see before an estimate pulls your estimate towards it, even when you know it is random.

• Asch conformity experimentstype: effect · evidence: supported

  In Solomon Asch's experiments in the 1950s, people had to say which line was as long as another, after a group had unanimously given an obviously wrong answer.

• Availability heuristictype: effect · evidence: supported

  We judge how often something happens by how easily examples come to mind.

• Bystander effecttype: effect · evidence: supported

  The more witnesses there are to an emergency, the less willing each of them is to help.

• Clickbait (curiosity gap)type: effect · evidence: contested

  Headlines that don't tell you everything ("You won't believe what happened next") are supposed to make us curious and get us to click.

• Cognitive dissonancetype: effect · evidence: contested

  When you do something that contradicts what you believe, you feel a discomfort that you reduce by changing your attitude.

• Confirmation biastype: effect · evidence: supported

  People tend to seek, choose and interpret evidence in favour of what they already believe.

• Conjunction fallacytype: effect · evidence: supported

  A more detailed story seems more probable than part of it, although every added detail makes it less probable.

• Curse of knowledgetype: effect · evidence: supported

  Once you know something, it is hard to imagine how someone who doesn't know it thinks.

• Decoy effecttype: effect · evidence: supported

  A third option, clearly worse than one of the two main options, makes that option look better and get chosen more often.

• Default effecttype: effect · evidence: supported

  A pre-selected option, the one that applies if you do nothing, is chosen far more often than when it has to be chosen actively.

• Delayed gratificationtype: effect · evidence: contested

  The ability to give up a small, immediate reward for a larger one that comes later.

• Dunning-Kruger effecttype: effect · evidence: supported

  People with the weakest scores on a test overestimate their performance the most.

• Ego depletiontype: effect · evidence: failed to replicate

  The idea that willpower is a limited resource, used up by every act of self-control, was one of the most cited in psychology.

• Endowment effect and status quo biastype: effect · evidence: strong

  Something seems more valuable once it is ours, and an option seems better when it is the one we already have.

• Facial feedbacktype: effect · evidence: supported

  The idea that your facial expression influences your emotions, for example that smiling makes you a little happier.

• Framing effecttype: effect · evidence: strong

  The same choice, described in terms of gains or of losses, gets different answers.

• Fundamental attribution errortype: effect · evidence: supported

  When we see someone do something, we tend to explain it by who they are rather than by the situation they are in, even when the situation explains everything.

• Gambler's fallacytype: effect · evidence: supported

  After a run of identical outcomes in a game of chance, we expect the opposite outcome to be "due", although the odds haven't changed.

• Growth mindsettype: effect · evidence: contested

  The idea that abilities can grow with effort should help students learn better.

• Habit formationtype: effect · evidence: supported

  A habit forms by repeating the same behaviour in the same context until it becomes automatic.

• Halo effecttype: effect · evidence: strong

  The halo effect means that a positive trait that stands out, especially good looks, makes us assume a person has other qualities too.

• Hawthorne effecttype: effect · evidence: contested

  The Hawthorne effect is the idea that people behave differently simply because they know they are being observed or studied.

• Hindsight biastype: effect · evidence: supported

  Once we learn how something turned out, it seems to have been predictable and we feel "I knew it all along".

• Hot hand fallacytype: effect · evidence: contested

  For more than 30 years, believing in an athlete's streaks of success was considered an illusion.

• Illusion of controltype: effect · evidence: contested

  We behave as if we could influence things that depend only on chance.

• Learning stylestype: effect · evidence: failed to replicate

  The idea of learning styles says that each person is "visual", "auditory" or another type and learns better when teaching matches their style.

• Loss aversiontype: effect · evidence: supported

  A loss weighs more than a gain of the same size.

• Milgram experimenttype: effect · evidence: supported

  In Stanley Milgram's experiments of 1961–1962, many ordinary people kept giving what they believed were painful electric shocks to a stranger because an experimenter asked them to.

• Moral licensingtype: effect · evidence: contested

  The idea that after a good deed people allow themselves a less good one started from small studies.

• Negativity biastype: effect · evidence: supported

  A loss, a criticism or a bad day counts for more than a gain, a compliment or a good day of the same size.

• Outcome biastype: effect · evidence: strong

  We judge a decision by how it turned out, not by how well it was thought through with what was known at the time.

• Peak-end ruletype: effect · evidence: supported

  When we remember an experience, we judge it mostly by its most intense moment and by how it ended, and its length matters surprisingly little.

• Planning fallacytype: effect · evidence: supported

  People usually underestimate how long their own projects will take, even when they know that similar projects ran late.

• Power posingtype: effect · evidence: failed to replicate

  The idea that two minutes in a wide, "superhero" posture changes your hormones and makes you bolder didn't survive replication.

• Primingtype: effect · evidence: contested

  A word you see now makes you recognise related words faster.

• Pygmalion effecttype: effect · evidence: supported

  The Pygmalion effect is the idea that pupils from whom teachers expect more end up actually doing better.

• Serial position effecttype: effect · evidence: strong

  From a list, we remember the last items best and, somewhat less, the first ones.

• Stanford prison experimenttype: effect · evidence: failed to replicate

  In 1971, Philip Zimbardo split students into guards and prisoners in a makeshift prison, and the experiment was stopped after six days because of the abuse.

• Stereotype threattype: effect · evidence: failed to replicate

  The idea: remind someone of a negative stereotype about their group, for example that women are worse at maths, and their test scores drop.

• Sunk costtype: effect · evidence: supported

  Money, time or effort already spent won't come back, whatever you decide now.

• Zeigarnik effecttype: effect · evidence: failed to replicate

  The idea that you remember interrupted tasks better than finished ones has not held up.