The zero-sum bias

A cognitive bias that causes people to mistakenly believe that one party’s gains are directly balanced by other parties’ losses.

This bias encourages belief in an antagonistic nature of social relationships

For example, the zero-sum bias can cause people to think that there is competition for a resource that they feel is limited, in situations where the resource in question is actually unlimited and freely available.

It can generally be said to affect people on two scales:

• Individual scale. It causes people to mistakenly assume that there is intra-group competition for a certain resource, between them and other members.
• Group scale. It causes people to mistakenly assume that there is inter-group competition for a certain resource, between their group and other groups.

• People sometimes view membership in social groups as being zero-sum: belonging to one social group excludes you from being a member of a different group.
• People sometimes view gender hierarchies in the workplace as being zero-sum, which can cause them to be more opposed to gender-fair policies.
• People sometimes believe that there is an inherent zero-sum competition between different ethnic groups, which can cause them to develop negative attitudes towards immigrants.
• People sometimes view racism as a zero-sum game, meaning that they believe that a decrease in racism against one group will be balanced by an increase in racism toward other groups.

• Mistaken belief in limited resources: assumeing that a certain resource is more limited than is actually the case.
• Mistaken belief in trade-off consistency: assuming that there must be a tradeoff between the various advantages and disadvantages of each option, so that the options must be balanced overall.
• Common correlations: certain types of tradeoffs or problems tend to be frequently correlated with each other, which can cause people to assume that they exist even in situations where they don’t.
• Previous experience: people mistakenly assume that a certain situation is zero-sum because they were exposed to similar situations in the past that were in fact zero-sum. 

To reduce the degree to which you experience the zero-sum bias, you need to identify cases where you assume that a certain situation is zero-sum, and then assess the situation rationally in order to identify whether it is actually zero-sum, which you can do, for example, by asking yourself whether a resource under consideration is truly limited.