Paul Watzlawick, Janet Beavin Bavelas, and Don Jackson, prominent researchers of the Mental Research Institute in Palo Alto, CA (the Palo Alto Group), were among the first researchers to formulate two fundamental dimensions of all communication: Apart from their content or report level (what is said), all messages also carry a relational or command level (how it is said). This definition makes two important points that are the focus of this entry: (1) All messages contain information about the relationship, and (2) all relationships exist through and are defined by message exchange. Relational messages provide interactants with information about the nature of the relationship, the interactants' status in the relationship, and the social context within which the interaction occurs. Relational messages play a particularly important role in those interpersonal relationships that have the potential of becoming increasingly more interdependent (one partner responds to the behavior of the other partner). Because ...