Klein (1964) demonstrated that the difficulty in naming hues increased directly with the semantic proximity of the words in which the hues were printed. Interference was maximal when the words were the actual hue names printed in incongruous hues, minimal when they were unpronounceable nonsense syllables, and intermediate when they were English words unrelated to color. Klein's findings have been independently replicated and elaborated in several subsequent studies (Schiller, 1966; Bakan & Alperson, 1967; Grand, 1967;Gholson & Hohle, 1968a).Though these studies unambiguously establish the relation of interference with semantic proximity, they do not show why it is that an incongruous mixing of hues and hue names makes it difficult to name the hues, but interferes very little with reading the names. The present experiment was designed to see whether or not the effect was due to the fact that a verbal response was being used, and to ascertain whether or not the same sort of interference would be found with an attribute other than color. Klein (1964, p. 577) offers an explanation of the effect based upon the assumption that "the color names and the irrelevant color-words involve identical motor-responses." "Interference from the word consists essen tially in the disposition to say it. It is in this sense that we speek of 'competition' from the word [ibid., p.584]."Klein's motor-competition explanation appears to assume verbal response, though the task could equally well be performed with some other type of response, such as pushing an appropriately color-coded button. Under such circumstances, there would still be competition for the same motor response but it could hardly be argued that the response to the name would have greater strength than the response to the attribute.There is another peculiarity of the verbal responses that should be made explicit in this type of task. There is a more radically different relationship between the spoken word red and the printed word red than between the same spoken word and the hue of the ink in which the word has been printed. To use Fitts's (1967) term, there is a high degree of stimulus-response compatability in the spoken-printed word situation, and a completely arbitrary relation between the hue and the hue name. This compatability comes about because of the fact that the sequence of letter forms in the printed word is linked in an orderly way to sequence of uttered sounds in the spoken word even though this linkage in English is far from a one-to-one mapping. No such linkage exists between the hue of the ink and the form of the utterance of the hue name. Such compatability may well account for the well-established fact that it takes longer to name a series of attributes than to read a parallel series of attribute names (Gholson & Hohle , 1968b). One would expect this difference to be sharply reduced if a nonverbal response were used.It is probably an historical accident that the attribute of color has been used exclusively in this interference task. Analogous tasks c...