The FIRO (Fundamental Interpersonal Relations Orientation) Model was first introduced to describe group development (Schultz, 1958). It has since been applied to family therapy, family systems medicine, and family measurement. The Family FIRO Model was adapted to focus on the fundamental concepts related to family interactions. The model assumes that three domains of interpersonal needs must be present within healthy family functioning: inclusion, control, and intimacy (Doherty & Colangelo, 1984; Doherty, Colangelo, Green, & Hoffman, 1985; Doherty, Colangelo, & Hovander, 1991).
For clarification, some of the main terms and concepts of the model are explained below:
"Inclusion" suggests "who is in or who is out" of any particular group (Schutz, 1958). For our purposes here, we are talking about who is in or out of the stepfamily. Issues include not only membership, but the way members function through individual roles, their emotional connectedness with one another, and various ways they share meaning that defines the perceived sense of identity as an emerging family (Doherty, et al., 1991).
"Control" addresses "who is up and who is down" within the system. Control refers to influence and power the members exert upon one another especially during times of stress and conflict for the stepfamily. Control does not refer to hierarchy within the stepfamily, since the structure is addressed within the inclusion domain. An example of a control issue occurs when one member challenges the hierarchy with another. This attempt and resulting interaction is intended to assert influence, or control the other, to adjust the hierarchical structure within the family system.
"Intimacy" has to do with how close or how far away individuals are emotionally within the family system. Intimacy refers to the ways members share hopes, dreams, feelings, and vulnerabilities with other members of the family. Intimacy is not intended to be synonymous with a sexual relationship, although for partners, sexuality is often included in the interaction. Furthermore, intimacy implies that members demonstrate a degree of tolerance for expressing intense emotions and sharing trust.