232 POPULAR SCIENCE MONTHLY 



psychology is, " to determine the simple reaction-time, and from it to 

 find the factors of psycho-physical time — namely, perception-time, ap- 

 perception-time (or discernment-time), and will-time." 13 



Along this line laboratory investigation has been able to show that 

 the will does, as a matter of record, occasion changes in the central 

 physiological mechanism, and that these changes possess quantitative 

 differences having more or less definite relation to psychical activity. 

 By this I understand that the latent energy of the nerve-cells is sum- 

 moned to activity, and that, as a result, the brain labors hard. In our 

 own laboratory I have seen the subject of an attention experiment pour 

 with perspiration, although physically he was, to all appearance, quite 

 quiescent. No better proof of intense cerebral work could be desired. 

 And experiment simply attempts to relate this energizing to the con- 

 comitant psychological states. 



But Wundt has committed himself to the modern attitude even 

 further. In the first and second editions of his " Physiological Psy- 

 chology," he suggested that the frontal regions of the brain are related 

 to apperception as the " bearers of the physiological processes which 

 accompany the apperception of the presentations of sense." 14 In other 

 words, all stages of the apperceptive process are accompanied by a 

 fixed physiological activity. Beyond the circumstance that this assigns 

 a function to the frontal regions which, otherwise, stand out of dis- 

 tinct relation to the factors of consciousness, it must be regarded as a 

 speculation. Wundt himself, although he does not dismiss the 

 hypothesis, tends to minimize it from his third edition. Yet it serves 

 to show how persistently he clings to the true psycho-physiological 

 method even in regard to the most recondite operation of the mind. 



It remains to note that the influence of mind over body demands 

 study as much as the converse. If apperception be a legitimate supposi- 

 tion — and it would seem to be a hypothesis which at least accounts for 

 unquestioned facts, then it follows that we must estimate it, not by 

 external stimulus, but in terms of internal activity. And this, of 

 course, reminds us that psycho-physiological investigation has proved 

 the existence of an influential voluntaristic element. No doubt, to this 

 point, the former has claimed, and still claims, the lion's share of 

 experimental attention. So that, in many ways, the internal problem 

 awaits concentrated attack. That is to say, physical and physiological 

 problems, being so much more readily amenable to the new methods, 

 have tended to crowd out the distinctively psychological material. 

 Nevertheless, we have arrived at something analogous to a causal influ- 

 ence of the central nervous system upon what I shall call ideation. 

 This was the indispensable initial step. But yet, this causality is 



13 Ibid., p. 472. 



14 Second edition, Vol. I., p. 218. 



