Conditioned Approach and Contact Behavior toward Signals for Food or Brain-Stimulation Reinforcement

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Science  15 Sep 1972:
Vol. 177, Issue 4053, pp. 1009-1011
DOI: 10.1126/science.177.4053.1009


When presentation of a retractable lever always preceded food delivery, rats licked or gnawed the lever. They also approached but seldom orally contacted a lever signaling brain-stimulation reinforcement; instead, subjects sniffed, pawed, or "explored" the lever. Therefore, a Pavlovian conditioned stimulus evoked directed skeletal responses whose specific form depended on the forthcoming unconditioned stimulus.