Which groups do you belong to? While we may use the word “group” in everyday life to mean numerous things, sociologists define groups specifically. A group is a collection of two or more people who share an identity and interact with each other.

A group, at minimum, must include at least one other person besides yourself. However, there are limits to a group’s size. At some point, if there are too many people involved in the group it becomes impossible to coordinate activity (Flamino et al. 2021) and recognize that people are part of the group (Fine 2012). To be part of a group we have to identify with each other in some way. This identity could be based on our social position, such as our race, class, or gender. Or it could be based on our shared cultural interests, say if you are fan of a particular sports team, like the Portland Timbers, or television show. Interactions, in person or virtual, are also crucial in determining whether a collection of people is a group. If people are not interacting with some frequency it is hard to argue they are a group.

How is a group different from a crowd? Crowds are people who happen to be in the same place at the same time but who do not interact or share a sense of identity. An example could be walking down the street or riding public transportation in a busy city. We may be sharing the same spaces with each other, but we don’t share an identity or even verbally interact with other people in the setting. In public settings it is quite typical for us to engage in civil inattention. Where we unobtrusively acknowledge other people in a setting, while simultaneously preventing more personal forms of attention.

Sociologists have identified different types of groups we may belong to. These include primary and secondary groups. Primary groups are a small, intimate group whose members share face-to-face contact and emotional connections. Primary groups are typically those that are involved in our earliest socialization experiences. This includes our families, close friends, and significant others. Primary groups contrast with secondary groups, which are impersonal groups that are task oriented and interactions are typically formal, based on roles and statuses. Rather than serving our emotional needs, secondary groups help us get things done. They can help us complete big projects or assignments. This might include your co-workers or classmates.

5.2.1 In-Groups and Out-Groups

As we have explored earlier, groups can define who is accepted and who is not, determining access to valuable resources. Thinking about this, social psychologists identify in-groups and out-groups.

An in-group is one which we belong to and towards which we hold favorable opinions. The tendency to favor our in-groups develops from a young age. This favoritism develops quickly in young children, increasing up to about six years of age, and almost immediately begins to influence our behavior (Aboud 2003; Aboud and Amato 2001). Young children show greater liking for peers of their own sex and race and typically play with same-sex others after the age of three. And there is a norm that we should favor our ingroups: people like people who express in-group favoritism better than those who are more egalitarian (Castelli and Carraro 2010). Amazingly, even infants as young as nine months old prefer those who treat people like them well and dissimilar others poorly (Hamlin et al. 2013).

In-group favoritism is found for many different types of social groups, in different settings, on different dimensions, and in many different cultures (Bennett et al. 2004; Pinter and Greenwald 2011). In-group favoritism also occurs on trait ratings, such that in-group members are rated as having more positive characteristics than are out-group members (Hewstone 1990). People also take credit for the successes of other in-group members. People remember more positive than negative information about in-groups, while being more critical of the performance of out-group than of in-group members. They also believe that their own groups are less prejudiced than out-groups (Shelton and Richeson 2005).

An out-group is one we do not belong to and towards which we may hold negative attitudes. The tendency to see members of social groups as similar to each other is particularly strong for members of out-groups, resulting in out-group homogeneity—the tendency to view members of out-groups as more similar to each other than we see members of in-groups (Linville, Salovey, and Fischer 1986; Ostrom and Sedikides 1992; Meissner and Brigham 2001).

Out-group homogeneity occurs in part because we don’t have as much contact with out-group members as we do with in-group members, and the quality of interaction with out-group members is often more superficial. This prevents us from really learning about the out-group members as individuals, and as a result, we tend to be unaware of the differences among the group members.

Once we begin to see the members of out-groups as more similar to each other than they actually are, it then becomes very easy to apply our stereotypes to the members of the groups without having to consider whether the characteristic is actually true of the particular individual. If men think that women are all alike, then they may also think that they all have the same positive and negative characteristics (for example, they’re nurturing, emotional). And women may have similarly simplified beliefs about men (for example, they’re strong, unwilling to commit). This dynamic related to in-groups and out-groups is especially pronounced when racial and ethnic group membership is involved.

5.2.2 Reference Groups

A reference group is a group that people compare themselves to—it provides a standard of measurement. In U.S. society, peer groups are common reference groups. Kids and adults pay attention to what their peers wear, what music they like, what they do with their free time—and they compare themselves to what they see. Most people have more than one reference group, so a middle school boy might look not just at his classmates but also at his older brother’s friends and see a different set of norms. And he might observe the behaviors of his favorite athletes for yet another point of reference.

Some other examples of reference groups can be one’s cultural center, workplace, family gathering, and even parents. Often, reference groups convey competing messages. For instance, on television and in movies, young adults often have wonderful apartments and cars and lively social lives despite not holding a job. At all ages, we use reference groups to help guide our behavior and establish our social norms. So how important is it to surround yourself with positive reference groups? You may not recognize a reference group, but it still influences the way you act. Identifying your reference groups can help you understand the source of the social identities you aspire to or want to distance yourself from.