PROBLEMS OF EXPERIMENTAL PSYCHOLOGY 677 



simple psycho-physical determinations, and towards introspective 

 analysis; and that the experimental method has been continually 

 extended from the simpler processes to the more complex whether 

 to complexes hitherto untouched by experiment, or to unfamiliar 

 phases of familiar mental formations. All that a study of the jour- 

 nals can do is to quantify and define these facts. I should like to 

 add, however, that their study has brought home to me, in a very 

 vivid way, the immense complexity and far-reaching interconnection 

 of the mental life. The contents of experimental papers are often- 

 times so varied that only a classification a potiori is possible; 

 and, oftentimes again, results that are but incidental to the given 

 topic of investigation prove later on to be fundamental for pro- 

 blems from which this topic had seemed disconnected and remote. 



So much, then, by way of preparation. Let us now, in the light 

 of it, attempt to formulate the present problems of experimental 

 psychology. You will remember that I am speaking of experi- 

 mental psychology sensu stricto, of the experimental investiga- 

 tion of the normal, adult, human consciousness. I wish that I 

 could proceed systematically. But, in the existing condition of 

 the science, it is better to be topical. We may, however, begin in 

 a quasi-systematic way, by considering the three fundamental 

 problems of sensation, affection, and attention. 



(1) Sensation. The senses, viewed from the standpoint of 

 psychological knowledge, fall into three principal groups. We 

 know a great deal about sight and hearing; we know a good deal 

 about taste, smell, and the cutaneous senses; of the organic 

 sensations, with a very few exceptions, we know practically no- 

 thing. There is work to be done I say this emphatically in 

 every field; there is probably no single chapter in sense- psycho- 

 logy that may not, with advantage, be reopened. Nevertheless, 

 we know a great deal about sight and hearing; the literature of 

 these senses is voluminous; advance in our knowledge lies (I am 

 speaking in the large, and quite roughly) in the hands of the few 

 experts who have occupied themselves particularly with visual 

 and auditory problems. And we know a good deal about taste, 

 smell, and the cutaneous senses; although here, doubtless, there 

 is much steady work, rank-and-file work, yet to be done. We know 

 something of the organic complex concerned in active touch, and 

 something of the static sense. On the other hand, of the organic 

 sensations in general we know practically nothing. Here, then, as 

 I take it, lies the immediate sense-problem for experimental psych- 

 ology. When we remember the importance of organic sensation 

 in the affective life, its importance as the vehicle of sensory judg- 

 ments in psycho-physical work, the part it plays in the mech- 

 anism of memory and recognition or in the motives to action, 



