> A general belief system about the antagonistic nature of social relations, shared by people in a society or culture and based on the implicit assumption that a finite amount of goods exists in the world, in which one person's winning makes others the losers, and vice versa ... a relatively permanent and general conviction that social relations are like a zero-sum game. People who share this conviction believe that success, especially economic success, is possible only at the expense of other people's failures.
Zero-sum bias is a cognitive bias towards zero-sum thinking; it is people's tendency to intuitively judge that a situation is zero-sum, even when this is not the case. This bias promotes zero-sum fallacies, false beliefs that situations are zero-sum. Such fallacies can cause other false judgements and poor decisions. In economics, "zero-sum fallacy" generally refers to the fixed-pie fallacy.