‘They are conspiring against us’: How outgroup conspiracy theories stimulate environmental neglect in intergroup resource dilemmas

Abstract Natural resources are limited, and people often share these limited resources in groups, which creates an intergroup resource dilemma. To understand individuals' sustainable behaviours in intergroup resource dilemmas in the context of group interactions, the present research systematically investigates the effect of outgroup conspiracy theories on sustainable behaviours and preliminarily explores the internal mechanism underlying this effect. First, a survey study (Study 1) relying on real‐world intergroup relations first confirmed the negative correlation between outgroup conspiracy beliefs and sustainable intentions in intergroup resource dilemmas. Then, an online experimental study that utilized the real situation of a region in China (Study 2) tested the causal relationship between exposure to an outgroup conspiracy theory and sustainable intentions, as well as showing the mediating role of intergroup threat perception underlying this relationship. Finally, a preregistered experimental laboratory study (Study 3) further verified the causal effect of exposure to an outgroup conspiracy theory on sustainable behaviours, again confirming the mediating role of intergroup threat perception. In general, our research demonstrates that exposure to an outgroup conspiracy theory stimulates individuals' environmental neglect and reduces their sustainable behaviours by increasing their perceptions of intergroup threat when faced with intergroup resource dilemmas.