in participants requesting for partners with the same-shape choice as it progressed, although the initial choice of shape had no effect on payoffs. Toward the end of the experiment, this number stood at a substantial 87%, indicating the presence of in-group favoritism. Their study supported the hypothesis that the formation of cultural groups alters selective pressure facing individuals, and thus leads to certain behavioral traits being advantageous. Thus, if such selective pressures were present in past civilizations, where membership in a certain group is correlated with a certain behavioral norm, the emergence of in-group biases where it is beneficial to act in differing manners to members of the same group is certainly plausible. Gender differences Automatic bias for own gender Rudman and Goodwin conducted research on gender bias that measured gender preferences without directly asking the participants. Subjects at Purdue and Rutgers University participated in computerized tasks that measured automatic attitudes based on how quickly a person categorizes pleasant and unpleasant attributes with each gender. Such a task was done to discover whether people associate pleasant words (good, happy, and sunshine) with women, and unpleasant words (bad, trouble, and pain) with men. This research found that while both women and men have more favorable views of women, women's in-group biases were 4.5 times stronger than those of men and only women (not men) showed cognitive balance among in-group bias, identity, and self-esteem, revealing that men lack a mechanism that bolsters automatic preference for their own gender. Competition Using a publics-goods game, Van Vugt, De Cremer, and Janssen found that men contributed more to their group in the face of outside competition from another group; there was no distinct difference amongst women's contributions. Ethnicity-based favoritism In 2001 Fershtman and Gneezy found that men showed in-group biases in a "trust" game based on ethnicity, whereas this tendency was not present in women. The study aims to identify ethnic discrimination in Israeli Jewish society, and was conducted on 996 Israeli undergraduates. Groups were separated based on whether the participant's name was typically ethnically Eastern or Ashkenazic. Similar to a dictator game, subjects were instructed to divide a sum of money (20 NIS) between themselves and another player. Player A was told that any money sent over to Player B would be tripled, and Player B would receive details of the experiment, including the name of Player A and the transferred sum. Subsequently, Player