Summation of excitations during uncoditioned reinforcement of a conditioned reflex

Summary

After conditioned motor defensive reflexes had been developed in dogs using Protopopov's method, a comparison was made of the effects produced by unconditioned electrical cutaneous stimuli given either separately or together with conditioned stimulus. The strength of the unconditioned reinforcement ranged from threshold to submaximal values. It was shown that during unconditioned reinforcement there is a summation of the conditioned and unconditioned reflexes, two weak reflexes usually giving an effect which is greater than the sum of the separate values, while two moderate reflexes give a result which is almost equal to the summed effect. A strong and a weak or two strong reflexes give an effect which is equal to or slightly greater than the value of the strong reflex. the results obtained show that in the summation there may be either facilitation or occlusion.