External objects and their qualities are verbali zed in the process of the development from nonverbal congnition to verbal congnition. Pavlov defined the word as the signal of signal, and Vygotsky emphasized the necessity of the psychological researches of speech as the mediational link which determines human behavior. But we have yet no psychological research that has applled these views concretely. We will start with the problem : what is the psychological meaning of the "verbalization"? When we try to classify some objects into some 'categories, we must cognize not only the quality which each object has, but that which it has not. In this study, our task is to solve the problem how some non-attachlng quality becomes cognized, and make the role of "verbalization" in this process clear.