Recent research in the conditioning of verbal behavior offers support to a learning-theory interpretation of changes that may occur in psychotherapy. Manipulation of awareness states, use of verbal conditioning as an independent variable, and effect of the reinforcement history of S in verbal conditioning experiments are being explored in relevance to controlled and measurable modification of verbal behavior. Evidence is accumulating that the generalization of an experimentally acquired verbal response is a function of the common cue-producing properties of the several classes of which it may be a member.