Some of the specific learning and motivational variables involved in desensitization therapy were investigated. Two factors were considered: group interaction as a source of motivation and discrimination learning, and the effect of a progressive hierarchy of problem-related situations upon anxiety arousal. The design of the study involved a 2x2 paradigm with a no-contact control group. Groups were formed according to two dimensions: the amount of group interaction and the nature of the desensitization hierarchy. Subjects were 25 psychology students in the upper 30% of the Test Anxiety Scale (TAS). Results indicated that test anxious college students completing a short-term program of group desensitization tended to report more anxiety reduction and achieve a greater increase in grade point average (GPA) than students with equivalent TAS scores who did not participate in a desensitization program. Motivational variables were more plausible than discrimination learning variables. The lack of significant differences between Progressive and High Anxious groups brings into question the necessity of using a progressive hierarchy when treating test anxiety and adds to the evidence against the advantage of using displacement to resolve certain conflict situations. (PS)