Reference groups refer to all the groups that have a direct (face-to-face) or indirect influence on their attitudes or behavior.. Groups have a direct influence are called membership groups. Some of these are primary groups with whom the person interacts fairly continuously and informally, such as family, friends, neighbors, and coworkers. Peoples also belong to secondary groups, such as religious, professional, and trade-union groups, which tend to be more formal and require less continuous interaction.
Reference groups influence members in at least three ways. They expose an individual to new behaviors and lifestyles, they influence attitudes and self-concept, and they create pressures for conformity that may affect product and brand choices. People are also influenced by groups which they do not belong.