How we judge others

• 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.

• Bystander effecttype: effect · evidence: supported

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

• Confirmation biastype: effect · evidence: supported

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

• Curse of knowledgetype: effect · evidence: supported

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

• 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.

• 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.

• 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.

• 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.

• Pygmalion effecttype: effect · evidence: supported

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

• 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.