This study looked at how people from areas of past violent conflict, like Syria and Iraq, decide to do business with others from different groups. They found that when others from different groups were thought to hurt them or their families, people were less likely to trade fairly with them. People tended to share more with their own group and use money-based deals with different groups who seemed harmful. If individuals from their own group had hurt them, they also used money-based deals with them. So, how people treat each other in business isn't just about group labels, like in-group and out-group, but also about past actions between them.