The aim of this experiment was to test the hypothesis that anxiety-reduction acts as a reinforcing state (as defined by the law of effect). 3 experimental procedures, designed to provide 3 different degrees of anxiety-reduction, were conducted with rats and guinea pigs. The results indicate that anxiety-reduction is positively correlated with learning, thereby supporting the supposition that it is a reinforcing agent. The implications of the findings are discussed and contrasted with alternative interpretations suggested by the conditioned-reflex conception of the learning process. The latter is found deficient because of its emphasis upon the importance of temporal contiguity of stimuli and its neglect of the factors of motivation and motivation-reduction. (PsycINFO Database Record (c) 2006 APA, all rights reserved)