To use a favorite example of K�hler's, if conditioned to respond in a certain way to the lighter of two gray cards, the animal generalizes the relation between the two stimuli rather than the absolute properties of the conditioned stimulus : it will respond to the lighter of two cards in subsequent trials even if the darker card in the test trial is of the same intensity as the lighter one in the original training trials.
42.
To prevent his system from being seen as mechanistic or reductionist while, also trying to draw a basic distinction between animal and human learning, Pavlov wrote in 1927 : Of course a word is for man as much a real conditioned stimulus as are other stimuli common to men and animals, yet at the same time it is so all-comprehending that it allows no quantitative or qualitative comparisons with conditioned stimuli in animals . " In 1932, Pavlov made the claim that speech is signals of signals or second signals.
