Across a wide range of pressing global challenges from democratic erosion, pandemics, climate change and economic development, there is an underlying psychological feature that presents a barrier to progress: zero-sum thinking.

Zero-sum thinking is a tendency to perceive a situation as a zero-sum game, where for one player to win, another must lose. In a zero-sum game, winnings exist in a fixed amount. Therefore, any gain for one party must come at the expense of others, rendering mutual gain, or mutual loss, impossible. Though purely zero-sum situations are extremely rare in lived reality, zero-sum beliefs are not. That is, people often perceive relationships to be zero-sum even when they are explicitly not so. Such zero-sum beliefs undermine potential cooperation towards achieving shared goals and overcoming shared challenges.

While a small, but growing, literature examines the causes and effects of zero-sum beliefs within particular situations and domains, this research investigates whether people might hold an implicit belief that relationships in general are like a zero-sum game. I propose that such a belief, which I call zero-sum mindset, predisposes one towards zero-sum thinking and its consequences across a wide variety of situations and domains.

At the crossroads of social psychology, which emphasizes the “power of the situation,” and personality psychology, which emphasizes the importance of “individual differences,” this research examines individual differences in perceptions of one’s general situation. My research demonstrates that when one holds a generalized construal of social interactions as a zero-sum game, the power of the perceived zero-sum situation forms a stable pattern of perceptual tendencies, motivations, and strategies.

Using a multi-method approach (including experiments, economic games, panel data, and large-scale multi-national surveys), I have examined the effects of zero-sum mindset in more than 10,000 unique participants across six countries and three continents. In the research presented here, I refine the concept and measurement of a zero-sum mindset. I also examine its breadth and stability, presenting evidence that a zero-sum mindset predicts zero-sum thinking and its cognitive and strategic corollaries across time and a variety of domains and situations. Finally, after demonstrating the consequences of the broader mindset, this research also examines the downstream effects of a zero-sum mindset on specific zero-sum beliefs that impact intragroup and intergroup relationships. Altogether, I find that zero-sum beliefs impair trust and cooperation, and motivate dominance and aggression strategies across a wide variety of situations and domains.