Being member of a group influences our thoughts, feelings and actions. Self-categorization is the process of seeing oneself as a member of a social group. It is flexible and can readily shift depending on the social context. Social identity refers to the way we feel about group memberships that we share with others. People learn about their own group in the same way they learn stereotypes of other groups. Group membership can influence who someone is.

There are several ways through which we feel like a group member:

1. Direct reminders of membership
   Direct reminders of group membership, such as a name or the presence of in-group members can help us feel like a group member.
2. Presence of out-group members
   The presence of an out-group member can be a reminder of our own group identity.
3. Being a minority
   People are more likely to think of themselves in terms of their memberships in smaller groups than in larger ones. Being a minority can serve as a reminder of our own group membership.
4. Conflict or rivalry
   A conflict or rivalry can remind us of our group membership and make people feel more like a member of a group.

Seeing oneself as a group member means that the group’s typical characteristics become norms or standards for one’s own behaviour. Bask in reflected glory (BIRG) is a way of boosting self-esteem by identifying oneself with the accomplishment or good qualities of fellow in-group members (e.g: being happy when a football team has won). People experience emotions in response to events that affect their group because identification with a group makes the group part of our self. We experience emotions as group members, which influences how we feel about and behave toward out-groups. Perceiving differences with other groups makes us feel unique, while similarities with our own group make us feel connected. Relatively small groups seem to provide the best balance between similarity and uniqueness.

A social identity links the individual to others and therefore influences the way the person thinks, feels, and acts toward other in-group members. People mostly perceive similarities between themselves and in-group members, which results in seeing our own group as more similar to ourselves. Anything that increases the accessibility of group membership enhances the assumed similarity. Learning about the personal qualities of others in the group helps us find our own place in the group. People tend to like in-group members more than out-group members. In-group members are sometimes not liked as individuals, but as representatives of the liked group (the in-group). Groups prosper when their members are willing to subordinate personal interests to the group. People treat in-group members with more fairness and show more altruism than they do towards out-group members.

Categorization into an out-group has a range of negative consequences. The out-group homogeneity effect refers to the tendency to see the out-group as relatively more homogeneous and less diverse than the in-group. There are several explanations for this effect: familiarity (1), we know more about the in-group and can thus better differentiate and the constrained nature of typical interactions with the out-group (2), because we tend to not have individual interaction with out-group members, thus making it difficult to differentiate between people in the out-group (e.g: Europeans recognize differences between people in Europe, but not between people in Asia). The out-group homogeneity effect extends to the perception of physical characteristics. The cross-race identification bias refers to the improved ability to remember faces from one’s own race than from another race. Unless people are aware of the bias and are motivated to overcome this bias, the bias appears.

A minimal intergroup situation refers to a research situation in which people are categorized, on an arbitrary or trivial basis, into groups that have no history, no conflicts of interests and no stereotypes. In this situation, people favour their own group. People want to make sure that their group has the edge over another group. The social identity theory states that people’s motivation to derive self-esteem from their group memberships is one driving force behind the in-group bias. There is a difference between in-group favouritism and out-group hostility. Out-group hostility occurs when in-group preference is joined by threat or conflict.

People tend to discriminate out-group members when their self-esteem is threatened. If the out-group is competing with the in-group, this can lead to intergroup discrimination. Unequal status amplifies intergroup discrimination. The hatred between groups usually arises when the in-group perceives that the out-group threatens the in-group’s existence. Moral exclusion is viewing out-groups as subhuman and outside the domain in which the rules of morality apply. Discrimination towards out-groups may be stronger in collectivistic cultures.

Stereotype threat is the fear of confirming others’ negative stereotype of your group. The knowledge of a negative stereotype about your group may cause anxiety and reduced performance. Worrying about not confirming the negative stereotype may use cognitive workload and this can reduce your performance. Self-affirmation, focussing on other positive group stereotypes and the presence of a role model (e.g: someone with high performance) can protect from the stereotype threat. Belonging to a negatively regarded group can have a negative influence on self-esteem.

When a member of a devalued group is treated badly, attributional ambiguity is created. Treatment might have been because of group membership or because of the situation or the person. Attributing negative outcomes to prejudice against one’s group can increase self-esteem. Intragroup comparisons can help boost self-esteem and can show us that some in-group members are doing particularly well.

People may turn to other solutions when self-protective strategies are ineffective. Individual mobility is a strategy of individual escape, either physical or psychological from a stigmatized group. If there is enough individual mobility, stereotypes may change over time. There are two ways to achieve individual mobility:

1. Disidentification
   This is the way of psychological escape from a stigmatized group. This can be done by avoiding reminders of membership, publicly criticizing the group and considering oneself an exception rather than a typical group member.
2. Dissociation
   This is the way of physical escape from a stigmatized group. This is concealing certain characteristics of physically leaving. Online support groups involving concealable characteristics were more important to the lives of their members.

Social creativity is introducing and emphasizing new dimensions of social comparison on which a negatively regarded group can be seen as superior. This can be done when an escape is difficult. Social creativity strategies were used more when the group boundaries were relatively fixed. It may not help against discrimination and can even rationalize it.

Social change refers to the strategy of improving the overall societal situation of a stigmatized group. Social change is generally preferred by people who strongly identify with their group. Social competition is the strategy of directly seeking to change the conditions that disadvantage the in-group. This strategy leads to in-group bias. Calling attention to discrimination is necessary for social change, but may lead to an increase in intergroup hostility.

Strategies that can reduce prejudice toward groups often undermine desires for social competition. Positive contact between groups and focussing on similarities may reduce prejudice, but might cause people to ignore actual inequalities between the two groups.

The effectiveness of each method of dealing with being a member of a stigmatized group depends on the size of the group, the resources its members control, the ease or difficulty concealing or changing group membership and the personal significance of group membership. The two most important factors that affect the strategy people choose are the strength of their group identification (1) and their perceptions of the possibility of individual mobility (2).