The vast amount of research we have reviewed in the last four chapters has spawned a proliferation of terms to describe adaptation patterns in interpersonal interaction. The lack of consensus on how terms are being used has made it extremely difficult to determine where research findings are similar or different and where theorists are making the same or different predictions. Our objective in this chapter is to sort through this morass of labels for patterns, identifying what we consider as the crucial features associated with each pattern, and to propose some definitions that we hope will become standard usage in the future. Because we are especially interested in those interaction patterns where people are actually adapting to one another, our focal point for drawing distinctions will be the accommodation patterns of reciprocity, convergence, compensation, and divergence.

But first, we should answer the question, why should we care about definitions? There are at least three reasons: (1) If students of interpersonal interaction are to talk with one another, we must have a common vocabulary. We must be able to assume that if we use the term “reciprocity,” for example, we share the same understanding of all that is implied by it. (2) We need greater precision in describing how people actually behave. To deduce what evidence exists for each of the patterns, we have to be sure that we have been connecting the right observations to the right patterns.