The clinical research reported here has two thrusts or purposes: one theoretical and one practical. The theoretical question can be stated: Is psychotherapy in general, and group psychotherapy in particular, a lawful, directive, and predictable process that can be understood from a behavioural or learning point of view? The second question and the more practical and down-to-earth one, is whether analyzing group therapy from a learning point of view can suggest and direct our attention to practical improvements in the technical work that we carry out as group therapists, whatever our theoretical persuasions.