Bison, IvanoColazzo, LuigiMalinverni, DanielaMich, Luisa2017-04-152017-04-151989This article sets out a quantitative theory of the interaction among subjects which allows a: description of the pragmatic aspects of communication. Within a system of interacting subjects each individual is described by means of a set of interaction parameters. 'In this \Alay an interaction paHern reiativs to each subject can be' defined. The model provides a "change law" which describes the evolution of individual patterns as a consequence of different communication events. This allows interactiqn deficiencies to be identified and suggests possible strategies for dealing with them. The theory was first developed in the area of clinical psychiatry and underwent two kinds of external verification: one psychometric-diagnostic, the other clinical. The theory was then applied to an economic environment in the behavioral study of decision-making processes. In this paper we suggest that it may be applied to the development of user models in computerized environments for cooperation support.enText