Change in the signal properties of a conditioned stimulus during two-way avoidance conditioning in rats

Acquisition of two components of conditioned active avoidance behavior by rats was studied. First presentations of electroshock evoked a number of different behavioral reactions. However, after five trials many rats learned to escape punishment running away to another part of a shuttle-box. The efficiency of the avoidance reaction conditioning significantly depended on the ability of an animal to learn the correct escape reaction to the unconditioned stimulus. However, some animals were incapable for acquisition of the conditioned reaction despite their high level of successful escapes. Increase in the number of negative reactions to the conditioned stimulus (light) at the next stage of learning suggests that the conditioned stimulus becomes the signal of forthcoming punishment. The ability of an animal to identify the conditioned stimulus as a signal significantly affected the efficiency of conditioned avoidance acquisition.