If they don't care, I won't share: Feeling unrelated to one's in?group increases selfishness instead of behavior for the greater good

Individuals cooperate more with others to whom they feel connected. As a consequence, reduced belonging an in-group decreases cooperation this group, but not others. Sometimes, however, there may be no new group available (re)affiliate with. In case, either increase on higher level, such as the superordinate humanity, or selfishness. We investigate in online experiment and survey study. Study 1 (N = 299) showed that being ostracized Cyberball ostracizers increased selfish behavior, while humanity did increase. Similarly, 2 1300) lower feelings of were associated selfishness, fewer participants decided donate humanitarian cause. These findings highlight importance inclusion integration for societies communities who wish maintain high level cooperation.