Belief in a just world or belief in just others? a study on the object of belief in a just world.

Abstract

Background: While belief in a just world has been extensively studied, the object of this belief still requires further specification. This study distinguishes two sources of uncertainty in future returns-nature and other people-and investigates whether belief in a just world is specifically directed toward human-sourced uncertainty but not nature-sourced uncertainty.

Methods: To test this hypothesis, an experiment was conducted in which participants decided whether to make an investment based on their beliefs about the return they would receive from another player. The identity of the other player was varied (computer or human, representing nature-sourced uncertainty and human-sourced uncertainty, respectively), and participants' level of belief in a just world was manipulated using a priming method. Multiple statistical analyses were conducted to examine the differences in investment behavior and expected returns between computer and human conditions.

Results: When interacting with human players, participants in the just-world priming condition showed significantly higher investment rates and expected returns compared to those in the unjust-world priming condition. In contrast, when interacting with computer players, the differences between just-world and unjust-world conditions were non-significant, both for investment rates and expected returns. Mediation analysis further revealed that expected return mediated the relationship between priming condition and investment behavior in the human player condition.

Conclusion: These findings demonstrate that belief in a just world influences decision-making when interacting with human players but not with computer players, supporting our hypothesis that belief in a just world mainly targets human-sourced uncertainty but not nature-sourced uncertainty. This research advances our theoretical understanding of belief in a just world and contributes to our understanding of its functions for both individuals and society.