The authors discuss several studies all of which demonstrate that duration of self-disclosure is a reliable component of the interpersonal process. They review other aspects of self-disclosure including that: (1) the act of revealing is not rewarding per se but can lead to rewards depending on the interpersonal nature of the situation; (2) socially isolated or closed situations encourage accelerated self-disclosure, especially in intimate areas of exchange; and (3) verbal exchange is a key process in interpersonal development. According to the authors, the non-verbal response of "amount of time talked" proves to be the most fruitful aspect of self-disclosure because it offers a additional advantages to studying the interpersonal process. Time spent talking can be easily measured with a pocket stop-watch. Subjects are not aware that the length of their disclosures is being taped; hence, it is impossible for them deliberately to distort their responses. The authors attest to the measure's sensitivity and usefulness as witnessed by the stability of findings across studies. (Author/PC)