Conditioned Excitors and Human Sense Organs

Abstract

ABOUT ten years ago, Alexey Bogoslavsky and Krikor Kekcheyev in Moscow and Alexander Dolin in Leningrad, working independently, demonstrated experimentally that the sensitivity of the human sense organs may be considerably modified under the influence of an indifferent factor, for example, the weak beat of a metronome, if it is accompanied several times by the influence of an active excitor. It was found that the latter, acting on an appropriate sense organ (for example, a sweet substance on the taste organ, or an odorous substance on the sense of smell), simultaneously changed the sensitivity of the entire sensory sphere of the brain. As in other conditioned reflexes, already studied, in which the excited organs were the salivary glands or definite groups of muscles, so in the case of our sensory conditioned reflexes, one rule must be observed: the formerly indifferent, or, as Pavlov called it, the conditioned excitor must be 'reinforced' several days in succession by the action of an excitor which by itself always produces the desired effect (unconditioned excitor).