A questionnaire was disbributed to 56 individuals (28 heterosexual cohabiting couples, both married and unmarried) to test a nine-axiom theoretical system designed to explain and predict dyadic communication behavior and satisfaction levels in personal phase relationships. Questions were asked to measure such factors as the following: time spent in communication daily, the degree of intimacy experienced, the number of surprises in the relationship per week, the degree of "liking" felt for the partner and the estimation of the partner's liking in return, and levels of satisfaction for each year of cohabitation. The theory is derived from Berger and Calabrese's model of initial interaction and is based on attributional uncertainty reduction, used here to refer to interactants' levels of confidence in their own ability to retroactively explain and proactively predict their partner's behavior. Data support eight of the nine axiom-specified hypotheses. Tables and graphs are included. (Author/DF)