| Term | Definition |
| Obligatory Interdependence | Because of our evolutionary history, it is necessary that we rely on the group for survival as species. |
| Group | A collection of people who are perceived to be bonded together in a coherent unit to some degrees. |
| Common-bond groups | Groups that tend to involve face-to-face interaction and in which the individual members are bonded to each other. |
| Common-identity groups | Face-to-face interaction is often absent, and the members are linked together via the category as a whole rather than each other. |
| Entitativity | The extent to which a group is perceived as being a coherent entity. |
| Status | The individual's position or rank within the group. |
| Roles | The set of behaviors that individuals occupying specific positions within a group are expected to perform. |
| Norms | Rules or exceptions within a group concerning how its members should (or should not) behave. |
| Collectivism | Groups in which the norm is to maintain harmony among group members, even if doing so might entail some personal costs. |
| Individualism | In such groups the norm is to value standing out from the group and being different from others; individual variability is to be expected and disagreement among members is tolerated. |
| Cohesiveness | All forces that cause group members to remain in the group. |
| Politicized Collective Identity | Recognizing shared grievances and engaging in a power struggle on behalf of one's devalued group. |
| Ideology | The philosophical and political values that govern a group. |
| Schism | Splintering of a group into distinct factions following an ideological rift among members. |
| Distraction-Conflict Theory | A theory suggesting that social facilitation stems from the conflict produced when individuals attempt, simultaneously, to pay attention to the other person present and to the task being performed. |
| Additive Tasks | Tasks for which the group product is the sum or combination of the efforts of individual members. |
| Evaluation Apprehension | Concern over being evaluated by others. Such concern can increase arousal and so contribute to social facilitation effects. |
| Social Loafing | Reductions in motivation and effort when individuals work in a group compared to when they work individually. |
| Hooliganism | Negative stereotype about how people behave in crowds at sporting events, especially applied to incidents involving England's soccer fans. |
| Deindividuation | A psychological state characterized by reduced self-awareness brought on by external conditions, such as being an anonymous member of a large crowd. |
| Cooperation | Behavior in which groups work together to attain shared goals. |
| Conflict | A process in which individuals or groups perceive that others have taken or will soon take actions incompatible with their own interests. |
| Social dilemmas | Situations in which each person can increase his or her individual gains by acting in one way, but if all people do the same thing, the outcomes experience by all are reduced. |
| Bargaining (negotiation) | A process in which opposing sides exchange offers, counteroffers, and concessions, either directly or through representatives. |
| Superordinate goals | Goals that both sides to a conflict seek and that tie their interests together rather than driving them apart. |
| Distributive Justice (fairness) | Refers to individuals' judgments about whether they are receiving a fair share of avaliable rewards- a share proportionate to their contributions to the group or any social relationship. |
| Procedural Justice | Judgements concerning the fairness of the procedures used to distribute avaliable rewards among group members. |
| Transactional Justice | Refers to the extent to which people who distribute rewards explain or justify their decisions and show respect and courtesy to those who receive the rewards. |
| Decision Making | Processes involved in combining and integrating avaliable information to choose one out of several possible courses of action. |
| Group Polarization | The tendency of a group member to shift toward more extreme positions than those they initially held by the individual members as a result of group discussion. |
| Groupthink | The tendency of the members of highly cohesive groups to assume that their decisions can't be wrong, that all members must support the group's decisions strongly, and that information contrary to it should be ignored. |
| Brainstorming | A process in which people meet as group to generate new ideas freely. |