The Negativity effect reference article from the English Wikipedia on 24-Apr-2004
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Negativity effect

The negativity effect is an attributional bias that occurs when subjects are asked what they think caused actions of other people whom they dislike. Under these conditions, the positivity effect is reversed and people rate the positive behavior of those they dislike to the situation and their negative behavior to something in their inherent disposition.

The negativity effect is sometimes called the ultimate attribution error because of its clear role in racial prejudice. (See fundamental attribution error.)

See also: trait ascription bias, list of cognitive biases.