ABSTRACT
Self-interested unethical decisions are prevalent in crowded environments. Although previous research has examined cultural and socioeconomic predictors of such decisions, there is a lack of research on how an individual’s perceived ecological environment influences these behaviours. Based on the behavioural ecological perspective and prior research, the present research examined the effect of social crowding on self-interested unethical decisions across four studies. An analysis of secondary data (N = 22,372; preliminary study) revealed that objective social crowding was associated with an increase in self-interested unethical decisions. A field experiment (N = 202, Study 1) and two laboratory experiments (N = 505, Studies 2 and 3) demonstrated that perceived crowding led individuals to make more self-interested unethical decisions and exhibit more unethical behaviours. Furthermore, this effect was mediated by reduced state self-control (Studies 2 and 3). These findings highlight the ethical and psychological costs of social crowding and offer practical implications for combating self-interested unethical decisions in socially crowded environments.