The influence of the probability of random performance of a reaction to be developed on the rate of formation of an instrumental reflex.

An instrumental defense reflex of pedal pressing during the action of a conditional signal (light) was developed in rats. The process of learning given a varying probability of the random performance of the instrumental reaction, p(a), which depends in particular on the duration of the intervals between the action of the conditional stimulus, was studied. It was shown that the rate of formation of a conditioned reflex is higher for p(a) = 0.25 than for p(a) = 0.05. The rate of formation of the conditioned reflex also depends on the frequency of the positive reinforcement of the correct reactions (from 50 to 100%). With a high p(a), the rate of formation of the reflex in question does not depend on the frequency of reinforcement of the positive responses; a feedback relationship is observed in the case of a low p(a). The hypothesis is advanced that not only does the behavior itself change the probability of contact with the external object but the original (a priori) probability substantially influences the formation of the behavior as well.