330 'Journal of Comparative Neurology and Psychology. 



3. Can Hans spell ? The letters of the alphabet were arranged in horizontal 

 rows on a board. Hans had to indicate first the row, and then the position in the 

 row, of each letter called for in the word. The experimenter did not know the posi- 

 tions of any of the letters of the alphabet except s and a (the positions of these were 

 purposely ascertained). Hans was asked to spell such words as "Schirm," "Arm," 

 "Rom" and "Hans." Under these conditions, Hans was a complete failure. . 

 Afterwards, when the questioner knew the positions of all the letters, the horse not 

 only could "spell," but also could answer questions involving several long words. 



4. Can Hans make arithmetical calculations .'' The method adopted in this test 

 was as follows: Herr von Osten would whisper a number into theear of the horse 

 which was unknown to the rest of the observers. Pfungst would then give another 

 number in the same way and then the horse was asked to add the two numbers. 

 The answer, of course, was unknown to all. In 31 tests of the above type, the horse 

 returned correct answers in three cases. In 31 cases where the questioner knew the 

 answer, 29 correct responses were made. 



5. Can Hans even count .? The Russian kindergarten counting device (aba- 

 cus) was used in this experiment. First, the questioner turned his back upon the 

 machine and then shoved forward a certain number of balls. (The questioner in 

 no case knew the number of balls which he had actually pushed forward.) The 

 horse was then asked to indicate the number of balls which had been advanced. 

 No correct answers were given. On the other hand when the questioner knew the 

 answer, Hans in all cases responded correctly. 



6. Memory tests. In the absence of the experimenter, a number, or the day 

 of the week, was mentioned to the horse which he was to indicatetotheexperimenter 

 when the latter returned. In ten trials, only two correct answers were returned. 

 One of the two correct answers was the number three which Hans always "played" 

 when in doubt. 



7. Musical memory. A little one octave harmonica was operated in an adjoin- 

 ing room. Hans was asked to indicate whether the first, second, or third, etc., tone 

 had been played. When not attended by the experimenter, the horse always failed. 

 When the questioner could be observed by the horse, all the answers were correct. 



In summarizing the results of these experiments, we find that when the questioner 

 knew the answer to the proposed query, from 90 to lOO per cent of the horse's 

 responses were correct. On the other hand, when the answer was unknown to 

 the questioner, the highest percentage of correct answers was 10. According to 

 the author, these latter correct answers must be ascribed to accidents. Pfungst 

 concludes "that Hans can neither read, count nor perform calculations with num- 

 bers. He can distinguish neither coins nor cards. He is not acquainted with the 

 calendar nor with our system of time. He cannot even recall a number given him 

 but a moment before. Finally, there is no trace of a musical ear. From all this, 

 we must conclude that the horse is unable to work independently, but is dependent 

 upon his environment for particular stimulations" (free translation). 



After the above data had been obtained, the author tested very carefully the 

 means by which Hans gets his cue. Without going into detail in this part of the 

 work, it may be said at once that if visual stimulation were cut oft by means of 

 blinders (the horse has a wonderfully wide field of vision) the horse could no longer 

 give the correct responses. In making his responses, it was observed that Hans 

 never looked at the objects to which he was supposed to react, but always at his 

 questioner. 



