evolved in small groups. This approach helps scholars to explain seemingly irrational behaviors like aggressiveness in politics and international society because "irrational behavior" would be the result of a mismatch between the modern world and evolutionary psychology. For example, according to evolutionary psychology, coalitional aggression is more commonly found in males. This is because of their psychological mechanism designed since ancestral times. During those times men had more to earn when winning wars compared to women (they had more chance of finding a mate, or even many mates). Also, the victorious men had more chance of reproduction which eventually led to the succession of aggressive, eager-to-war DNAs. As a result, the authors hypothesize that countries with more men will tend to show more aggressive politics thereby having more possibility of triggering conflicts within and especially among states. Indeed, some exceptions do exist in this theory as this is just a hypothesis. However, it is viable enough to be a hypothesis to be tested to explain certain political events like war and crisis. Terrorism On an individual level terrorism has been explained in terms of psychopathology. Terrorists have demonstrated to show narcissistic personality traits (Lasch, 1979, Pearlstein, 1991). Jerrold Post (2004) argues that narcissistic and borderline personality disorders are found in terrorists and that mechanisms such as splitting and externalization are used by terrorists. Others such as Silke (2004) and Mastors and Deffenbaugh (2007) refute this view. Crenshaw (2004) showed that certain terrorist groups are actually careful in not enlisting those demonstrating pathology. The authoritarian personality theory has also been used as an explanation for terrorist behavior in individuals. In terms of explaining reasons for which individuals join terrorist groups, motivational theories such as need for power and need for affiliation intimacy are suggested. Festinger (1954) explained that people often join groups in order to compare their own beliefs and attitudes. Joining a terrorist group could be a method to remedy individual uncertainty. Taylor and Louis (2004) explained that individuals strive for meaningful behavior. This can also be used to explain why terrorists look for such radical beliefs and demonstrations. Studies on children in northern Ireland by Field (1979) have shown that exposure to violence can lead to terrorist behavior later on. Implicating the effect of developing acceptable norms in groups. However this view has also been criticized (Taylor, 1998). Other theories suggest that goal frustration can result in aggression (Dollard,