Personalized interactions increase cooperation, trust and fairness

A new setup for social games suggests that when people are given the freedom to tailor their actions to different people in their networks, they become significantly more cooperative, trusting and fair. The international study with Kobe University participation thus argues that many standard experimental setups of cooperation underestimate people’s prosocial potential.

Games that are models of social interactions are used in sciences spanning from sociology and anthropology to psychology and economics, giving us very concrete data on how likely it is that people behave in a certain way in certain social contexts. For example, when modeling how people cooperate in social networks, one such game shows that only roughly one in seven people end up being cooperative in the long run. “Most experiments on games on networks, however, assume that players must act uniformly toward everyone in their network and overlook the capacity of humans to actively manage their social networks,” says Kobe University computational social scientist Ivan Romić.

Together with Danyang Jia and Zhen Wang at the Northwestern Polytechnic University in Xi’an, Romić therefore designed an experimental setup that allows players to choose different actions towards their various neighbors in the prisoner’s dilemma and the trust and ultimatum games, games that model social cooperation and fairness. They then recruited over 2,000 university students across China to play these games and varied the fraction of players who could choose their actions freely, allowing the researchers to find out how the freedom they afford their study participants influences the results.

In the journal Nature Human Behaviour, they published a paper rich with results. “In the prisoner’s dilemma, cooperation rates rose from just 14% in constrained populations to over 80% when everyone had full agency. Trust and fairness showed similar improvements. Even in mixed populations where only some players had agency, the prosocial effects were substantial, although they also produced temporary spikes in inequality as free players learned to use their flexibility,” summarizes Romić. Importantly, when all players were free to tailor their behavior, inequality decreased even as overall wealth increased.

The team also looked at how this behavior developed over time as the games were played repeatedly. Jia, who coauthored the study, says: “We found that players with more freedom expressed their prosocial tendencies right from the first round. This wasn’t just about learning over time but about having the capacity to act differently from the start. We also found that as players gained agency, populations shifted toward conditional and prosocial behavioral types, such as tit for tat cooperators and generous trustors. Constrained players, by contrast, tended to default to antisocial strategies — not necessarily because they were selfish, but because the environment limited their options.”

The team thus argues that many standard experimental setups of cooperation underestimate people’s prosocial potential by artificially restricting how social decisions are made. Their findings highlight the need for behavioral experiments to reflect the realities of social interaction, specifically that individuals often tailor their actions to different people in their networks, for capturing the true dynamics of social behavior. Romić adds, “More generally, this suggests that equal opportunity to individualize one’s interactions benefits prosocial behavior.”

This research was funded by the National Science Fund for Distinguished Young Scholars (grant 62025602), the National Natural Science Foundation of China (grants U22B2036, 62476221, 62366058), the Tencent Foundation, the Japan Society for the Promotion of Science (grants JP24K16333, JP25K01452), the National Fund of Philosophy and Social Science of China (grant 62473252) and the Shanghai Pujiang Program (grant 23PJ1405500). It was conducted in collaboration with researchers from the Northwestern Polytechnical University, the Yunnan University of Finance and Economics, Shanghai Jiao Tong University, the Ministry of Education of China, Shanghai Engineering Research Center of Intelligent Control and Management, Yunnan University, Aalto University and China Telecom Corp Ltd.

Kobe University is a national university with roots dating back to the Kobe Higher Commercial School founded in 1902. It is now one of Japan’s leading comprehensive research universities with over 16,000 students and over 1,700 faculty in 11 faculties and schools and 15 graduate schools. Combining the social and natural sciences to cultivate leaders with an interdisciplinary perspective, Kobe University creates knowledge and fosters innovation to address society’s challenges.