Discontinuity effect

The discontinuity effect is known as the tendency for the competitiveness displayed between different, interacting groups to be out of proportion and markedly greater to the competitiveness displayed between interacting individuals. Given that group competition over scarce resources is believed to lead to group-level conflict (see, realistic group conflict theory), it has been asserted that the link between competition and conflict is also considerably more powerful between groups than between individuals. Although individual group members may been cooperative in nature, once individuals join together to make collective unit, individual orientations favoring cooperation tend to be overshadowed by competitive orientations of the group.

Causes
The discontinuity effect is believed to emerge from several different causes that ultimately combine to intensify inter-group conflict. First of all, when individuals congregate to form groups, they typically become more greedy. This change in disposition develops as group members realize they are in competition with others to achieve group-level gains.

Secondly, people tend to fear aggregations of individuals (i.e., groups) more than they fear individuals in singularity. In general, groups are considered more abrasive (e.g., overtly competitive, aggressive) and less agreeable (e.g., helpful, trustworthy) than individual members. This pessimistic view can foster a generalized distrust in other groups as well as extreme paranoia and group-to-group tension.

Thirdly, group members sometimes feel pressure to maintain a sense of group duty - to do whatever they can to maximize the group's collective outcomes and to increase team achievement. This loyalty to service the in-group is thought to trigger a strong unified desire to compete with and outdo out-groups.

Fourthly, diffusion of responsibility is believed to contribute to the discontinuity effect. Individual group members generally feel that they are not entirely responsible for their own personal actions while their actions are carried out in a group setting. Given that individuals feel less accountable for their own actions when performed in the presence of others, this diffusion of responsibility is believed to play a role in promoting group-level shifts toward hostility and conflict. In addition to the potential causes of the discontinuity effect described here, other causes including feelings of anonymity and in-group favoritism have also been proposed.