Let us turn now, from the tests in counting and computation to those in reading. We have seen that Hans manifested his seeming knowledge of language symbols in a threefold manner: he might approach a slate on which was written the symbol asked for, or he would indicate its location in a series of slates by means of tapping, or finally by means of so-called spelling of the word which was written upon a slate or placard. The responses by means of approaching a placard were very often unsuccessful, while indications by means of tapping were scarcely ever unsuccessful. If it were true that higher intellectual
processes[T] were here involved, then the converse would have been expected, for tapping required not only the ability to read, but also the ability to count. If, on the other hand, we assume that the horse simply followed the directions given by the questioner's movements, this seeming difficulty resolves itself, for it would be more difficult for Hans to perceive the signs which he receives while moving than those which he receives while tapping. When we recall that it was easier to direct the horse to a placard near the end of a row than one nearer the center (see [page 81]), we can readily understand how it was that during the experimentation carried on by the September-Commission ([Supplement III; page 255]), Hans was able to point out immediately the placards on which were written the names "Castell" and "Stumpf", for they were at the two extreme ends, but was unsuccessful in locating the one on which was written the name "Miessner" which was not a bit more difficult to read, but was located at the fourth place in the row. He first approached the fifth card, then upon repetition of the test he pointed out the other neighboring tablet, viz., the third.
In spelling, Hans was quite indifferent whether his table with the eighty-four number signs upon it stood before him, for he had no knowledge of letters. Neither Mr. von Osten nor Mr. Schillings required it, for the former knew the table by heart and Mr. Schillings told me that before every test he made a note of the numbers which were necessary to indicate the required letters, trusting in this way to control the responses of the horse and never guessing that by so doing he was making it possible for the horse to answer correctly. The newspaper reports aroused much interest at the time by stating that Hans was able to spell such proper names as "Plüskow" and "Bethmann-Hollweg", even to putting in the difficult "w" and "th". The friends of Mr. von Osten at the same time called attention to the exquisite auditory acuteness of the horse which enabled him to perceive the aspirated "w" and to discriminate between the "th" and "t", (the "th" is softer than the "t" in German.—Translator). This explanation, of course, must have appeared somewhat daring even at that time.
Hans was quite guiltless of the many limitations imputed to him concerning his knowledge of symbols. That he was unable to read capitals or Latin script was merely a vagary of the master, like the belief that it was necessary to confine one's self in one's questions to a certain vocabulary and to a certain form. Mr. von Osten's apparent failure to elicit responses from the horse on topics of which it was ignorant is a beautiful illustration of the power of imagination. Mr. von Osten was convinced from the very first that Hans could not answer such questions. When the belief in success was lacking, of course there was not the requisite amount of concentration which, alone, leads to perceptible expressive movements and thus elicits a successful reaction on the part of the horse.
Mr. Schillings, owing to his great impressionability, remained long under the spell of Mr. von Osten's point of view. Thus I find in the record of the September-Commission that the question "How much is 3 plus 2?" was answered incorrectly by Hans, but he responded correctly the moment Mr. Schillings replaced the word "plus" which was "tabooed", by the word "and". For a long time also he could receive no response to questions put in French until one day he made the discovery that, curiously enough, the animal never responded adequately unless he himself firmly believed in the possibility of success. It is noteworthy that the Count zu Castell, independently of Mr. Schillings, made the same discovery. Mr. Schillings made his curious discovery—which he was unable to interpret, but which aroused some suspicion—on the following occasion. One day—whether accidentally or because his prejudice was temporarily overcome—he commanded; "Dis deux!". Hans responded promptly with 2 taps. He was greatly surprised and believed that Hans had gotten hold of the French by hearing it spoken in his environment. Possibly he understood also "trois" and "quatre"? He put the questions and received correct responses. He asked again, "dix", "vingt", and so on to "soixante". At
"soixante-six" he became doubtful. Indeed, Hans failed him. At "quatre-vingt", the game began again. "Cent", again, succeeded. The old saying that "Faith will move mountains" was verified once more.[U]
Hans's seeming knowledge of the value of coins and cards, of the calendar and the time of day, as well as his ability to recognize persons or their photographs, can now be readily understood. In all of these cases, we had to deal, in so far as knowledge is concerned, only with that of the questioner,—the horse simply tapped the number the questioner had in mind. The meaning which was supposed to be expressed by the tapping never existed as far as Hans was concerned; it was only in the mind of the questioner that the concepts: ace, gold, Sunday, January, were associated with "1", etc. The same was true with regard to all other wonderful feats of memory. The sentence: "Brücke und Weg sind vom Feinde besetzt", (The road and the bridge are held by the enemy), which was given to the horse one day and correctly repeated by him on the following day, was not an answer elicited from the horse by means of a question, but rather a system of automatic reactions which were induced by certain involuntary movements of the questioner as stimuli. Far from showing a wonderful memory in these feats—as is claimed for him by the very non-critical compiler, Zell[28]—Hans, on the contrary, has at his service a remarkably small number of associations. For, besides possessing the powers of any ordinary horse, he recognizes only a few meager visual signs. To be sure, we find in the literature a horse that was said to have recognized 1500 signals,[29] but all proof is lacking and the report is so meager that we cannot discover whether these signs were auditory or visual.[V]
Having thus disposed of all questions concerning the horse's apparent feats of reason and memory, let us turn to those in the field of sensation. We shall begin with vision. That Hans was unable to select colored pieces of cloth merely upon the basis of color quality, without reference to their order, was shown in [Chapter II]. It would, however, be somewhat hasty to infer color-blindness from this fact, as did Romanes[32] on the basis of similar unsucessful responses on the part of a chimpanzee ("Sally" of the London Zoölogical Garden). It is much easier to explain the failure of the horse than that of the monkey on the basis of intellectual poverty, a poverty of associative activity. It presumably can discriminate between the various colors, but it cannot
associate with these their names. The existence of chromatic vision in the lower forms is by no means as unquestionable as is assumed by popular thought. Even teleological considerations which are often brought forward (especially that of the ornamental and protective coloring of so many animals) can never do more than establish a certain probability. For definite proof, we need data given by observation (we have none in this case), or experimental evidence. Such evidence we have, but it is insufficient in quantity and unfortunately most of it was obtained under inadequate experimental conditions.[W] We know nothing regarding chromatic vision in the horse, though we have often had trained horses which apparently possessed color discrimination. The earliest report of this kind I find in a work published in the year 1573.[36] Here we read that a number of Germans exhibited two horses in Rome which could, upon request of their masters, point out those persons among the spectators who were wearing stockings of any designated color. The passage, "conoscevano i colori", (they recognized the colors,) proves nothing and no one has ever heard, even in modern times, of a horse that actually knew colors.