The battle against prejudice and inequality in our world could be won with the help of scientific and mathematical tools, according to a new study published in the journal Chaos by AIP Publishing.

The research, conducted by Luis A. Martinez-Vaquero from the Polytechnic University of Madrid, uses evolutionary game theory and complex system analysis to delve into the connection between inequality and intolerance.

Martinez-Vaquero’s findings reveal that inequality amplifies intolerance and proposes redistributing wealth as an effective way to curtail its spread.

In his research on cooperation, Martinez-Vaquero adopted an indirect reciprocity model, which stands in contrast to direct reciprocity. Unlike direct reciprocity, which relies solely on past interactions between two individuals, indirect reciprocity takes into account the role of a third party. In this approach, an individual forms a reputation for themselves based on their actions, which then influences how others perceive them and subsequently interact with them in future encounters.

“Thus, strategies under reputation-based indirect reciprocity consist of two parts: moral assessments, which dictate how individuals judge the interactions of others and attribute reputations, and action rules, which indicate how one should interact with others based on what these reputations are,” explains Martinez-Vaquero.

The research model involved dividing the population into two groups – high-income and low-income. The individuals were then randomly paired as donors or recipients, where the donors decided whether or not to donate funds to the recipients based on the reputation of both parties. The onlookers judged the donor’s actions as either “good” or “bad” and updated their reputation accordingly. Those who exhibited tolerance did not consider the income of the recipient while making the donation. Conversely, intolerant individuals considered income as a factor and gave a “bad” reputation to those from the opposite income group. Moreover, they also judged individuals from their own group as “bad” for cooperating with the opposite group.

“Inequality clearly enhances the emergence of intolerance, escalating it even without the presence of new individuals who bring these behaviors. Once intolerance begins to act, it is almost unstoppable in the presence of inequality,” remarks Martinez-Vaquero.

According to the study’s findings, there were instances where individuals from minority groups facing economic disadvantage preferred to assist wealthy individuals over their own community members, despite experiencing discrimination from wealthy individuals. However, the research highlights that redistributing wealth during the early stages of intolerance can be an effective measure to counter the spread of discriminatory behavior.

The study’s simplified model provides a basis for further exploration into how to prevent intolerance by addressing wealth inequality. It showcases the potential of complex systems, which have applications in a wide range of fields, including climate science, thermodynamics, chaos theory, and neural network computing.

Source: 10.1063/5.0135376

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