<p>Previous research on representatives’ decision-making preferences frequently employed random selection methods to explore differences in decision-making among individuals. However, how representatives earned responsibility could also shape their decision-making preferences. Thus, this study aimed to explore how representatives selected randomly versus those chosen through competition differed in their decision-making preferences within an environmental dilemma task. Representatives selected through competition were identified based on their superior memory skills demonstrated in a digit recall task. In the environmental dilemma task, representatives were tasked with contributing endowment to clean energy development, with the amount they contributed reflecting their decision preferences. The findings of the study revealed that representatives who attained their positions through competition, as opposed to random selection, contributed more money toward clean energy development (Study 1, Study 2, Study 3). Notably, factors such as a sense of responsibility, moral traits, and perceived power did not significantly impact their decision-making behaviors (Study 1, Study 2). Representatives selected through competition were more inclined to protect the environment and therefore contributed more money to developing clean energy (Study 2). Moreover, such representatives were more engaged in environmental protection actions, consequently resulting in more contributions to clean energy development. These environmentally protective behaviors partially mediated the influence of responsibility acquisition methods on representatives’ decision-making preferences (Study 3). These results suggest that within the environmental dilemma task, competitive selection methods prompted representatives to undertake more actions aimed at environmental protection and contribute more money toward clean energy development.</p>