2000 Volume 50 Issue 1 Pages 27-31
Several studies showed the second order conditioning with a first order backward conditioned stimulus as a reinforcer established an excitatory conditioned response to the second order conditioned stimulus, while no excitation to the first order conditioned stimulus being observed. But other previous studies failed to show the similar effects in other situations. The present experiment addressed to retest the effects in the rats' licking suppression, in which a great part of procedures was similar to those used in the successful previous studies, except with on-the-baseline technique that had never been adopted in any previous studies. As the result, the second order excitation was observed but no eminently first order excitation was seen; i.e., the second order excitation with first order backward conditioning could be successfully demonstrated.
