From Mazar and Aggarwal:
Why are there national differences in the propensity to bribe? To investigate this question, we conducted a correlational study with cross-national data and a laboratory experiment. We found a significant effect of the degree of collectivism versus individualism present in a national culture on the propensity to offer bribes to international business partners. Furthermore, the effect was mediated by individuals’ sense of responsibility for their actions. Together, these results suggest that collectivism promotes bribery through lower perceived responsibility for one’s actions.later note: I forgot to put the link to this article, it's now added.