THE AUTHOR'S INTROSPECTIONS 97 



leaping forward, etc. In this experiment, without excep- 

 tion, the spoken command evoked adequate reactions, — 

 the silent command, an incorrect response. Evidently 

 the impulse to movement was not so great with the mere 

 conceiving of " right ", " left ", etc., as when the words 

 were enunciated. It, therefore, required some practice 

 on my part before a sufficiently strong movement-impulse 

 became associated with the idea. All this is in no wise 

 at variance with the fact that tests involving counting and 

 computation were as successful when the problem was 

 given in silence, as when it was spoken. The signs for 

 tapping, viz. : inclination and erection of the head and 

 body, followed the question. The question therefore be- 

 came superfluous. On the other hand the signs for head- 

 movements on the part of the horse, were given while the 

 question was being put. I ask, which way is " upward ", 

 and at the same time I look upward. In this case there- 

 fore the question itself is not entirely insignificant. — I ex- 

 perienced greater difficulty in getting Hans to respond 

 with the head-movement to the left. After much prac- 

 tice I was able to evoke this movement by means of 

 giving the command aloud, but never by means of the 

 " silent " command. Accidentally I hit upon a device by 

 means of which I attained this end also. I asked the horse 

 aloud "Which direction is left?", — whereupon he re- 

 acted properly ; then I immediately repeated the question 

 silently, and was successful every time. My mental atti- 

 tude here was still the same as when I put the question 

 aloud. What sort of an attitude this was, I could not, of 

 course, have stated explicitly at the time. I could not, 

 therefore, awaken it at will, — and if I allowed but a 

 minute to elapse between the spoken and the silent ques- 

 tion, the vivid after-effect. (the so-called "primary mem- 



