Cross-cultural research has found differences in attitudes towards aggression in different cultures. In one questionnaire study of university students, in addition to men overall justifying some types of aggression more than women, United States respondents justified defensive physical aggression more readily than Japanese or Spanish respondents, whereas Japanese students preferred direct verbal aggression (but not indirect) more than their American and Spanish counterparts. Within American culture, southern men were shown in a study on university students to be more affected and to respond more aggressively than northerners when randomly insulted after being bumped into, which was theoretically related to a traditional culture of honor in the Southern United States, or "saving face". Other cultural themes sometimes applied to the study of aggression include individualistic versus collectivist styles, which may relate, for example, to whether disputes are responded to with open competition or by accommodating and avoiding conflicts. In a study including 62 countries school principals reported aggressive student behavior more often the more individualist, and hence less collectivist, their country's culture. Other comparisons made in relation to aggression or war include democratic versus authoritarian political systems and egalitarian versus stratified societies. The economic system known as capitalism has been viewed by some as reliant on the leveraging of human competitiveness and aggression in pursuit of resources and trade, which has been considered in both positive and negative terms. Attitudes about the social acceptability of particular acts or targets of aggression are also important factors. This can be highly controversial, as for example in disputes between religions or nation states, for example in regard to the Arab–Israeli conflict.