Orbeli's experimental work on color discrimination in dogs

In the 1900's, L.A. Orbeli, on I.P. Pavlov's request, attempted to establish color discrimination in dogs. Previous experiments used the motor discrimination method and gave inconsistent results. In contrast, Orbeli used the salivary conditional reflex method, which he considered to be more precise than the method that relied on erratic movements of a dog. After experimentation that lasted about one and a half years, Orbeli failed to establish color discrimination. When subsequent experiments by Russians and Germans yielded positive results with the motor discrimination method, Orbeli switched to this method and also obtained positive results. These findings were confirmed by most subsequent experiments on color discrimination in dogs. The utility of Pavlovian conditioning in sensory experimentation was not universally justified and its importance was greater in the study of learning.