Central inhibition-some refractory observations

The observation that the response to the second of two stimuli is delayed if a response has to be made to the first has led to the development of a theory of a central refractory state during which incoming stimuli cannot be elaborated. In the experiment reported here the two stimulus-response situations have been made as independent as possible, and under these conditions it is shown that this theory cannot be maintained in its present form. The concept that the central integrating mechanism readily becomes blocked by nay single stimulus is dismissed as nonproven and uneconomic. The present findings, however, confirm previous observations that some interference between the two situations may occur but indicate that this is not necessarily maximal immediately after the presentation of the first stimulus. It is tentatively suggested that the phenomena of central inhibition can be interpreted in terms of the interaction between the excitatory and inhibitory significance of the stimuli and the internal anticipatory set.