The present study using 16 Ss aimed at investigating signal relations between flash and click stimuli which were connected with either motor or verbal response. Ss were required to judge which one of these two stimuli appeared earlier. Interstimulus interval between two stimuli was 0 and 50 cosec, which were preceded by a warning stimulus (also flash or click). Differences in correct responding rates in varying stimulus and response connections and their correlations to personality inventory suggested that there may exsist signal similarity between the click stimulus and the motor response (first signal system predominating) and also between the flash stimulus and the verbal response (second signal system predominating).