Clever Hans

Wilhelm von Osten, a retired math teacher, spent fourteen years with his horses, every single day, rain or shine, in the back courtyard of his Berlin home located at Griebenowstraße 10, teaching them to recognize images, learn the alphabet, and calculate simple math problems. Only then, in 1904, did he go public with his stallion named Hans, acquired in the year 1900. The press response to Osten’s demonstrations was enormous, for after only two years of training, Hans could already “count, calculate using the main arithmetic types, spell, and read; he recognized the sounds, coins, cards, the pointer position of the clock, and even more…. Every day his tenants and neighbors could watch him at work and especially these regular observers had to realize that a real school lesson was being carried out here” (Krall Reference Krall1912, 17).Footnote ²

After four years of schooling, the ever-growing group of visitors and curious individuals experienced something like the following at the public demonstrations, which were free of charge:

Hans expressed himself primarily through discrete tapping signs in his “hoof language” (Hufsprache) (Pfungst Reference Pfungst1907, 157): “Since everything had been translated into terms which were to be expressed by means of tapping with the foot, and thus really put into terms of number” (Pfungst Reference Pfungst1911, 221), all information was articulated through hoofbeats on a board designed expressly for that purpose.

Wilhelm von Osten had a strong interest in having his pedagogical achievements in teaching Hans examined publicly, which is why he held free public demonstrations on a regular basis in the back courtyard of his tenement building. In the year 1904, a committee of thirteen specialists and scientists convened, and on September 12, 1904, they arrived at the verdict that “the possibility of tricks of the sort commonly used in training, was excluded” and therefore that Osten’s teaching success, “which has little in common with methods of training, and is patterned after the instruction given in the elementary schools,” was to be considered “worthy of a serious and incisive investigation” (Pfungst Reference Pfungst1911, 253–54).

Carl Stumpf, along with his assistant Erich Moritz von Hornbostel as the clerk recording the experiments and his student Oskar Pfungst as experimenter, spent several weeks working with Clever Hans, with Wilhelm von Osten, and with the Africa explorer Carl Georg Schillings, who had previously spent a considerable amount of time conducting experiments with this horse and was now likewise presenting the results to the public (see Gundlach Reference Gundlach2006, 99). To conduct their experiments, they erected “a large canvas tent” as an ambulatory psychophysical laboratory in Osten’s back courtyard in Berlin (Pfungst Reference Pfungst1911, 30). Their experiments were designed to verify one of the two hypotheses: the cultural-technical learning achievements versus the communication hypothesis.

The methodologically brilliant experimental approach taken by Pfungst lay in his idea to test whether Clever Hans would still remain clever when the experimenter poses both deliberate and undeliberate questions, meaning those “in which the procedure was without knowledge of the answer on the part of the questioner” (ibid., 32). Thus, if in the case of the undeliberate questions no deviations arose in the number of appropriate answers, it could then be said that communication was absent, and the horse’s cognitive ability proven by its mastery of elementary cultural abilities like speaking, calculating, and writing. Carl Stumpf viewed the cultural-technical education of Clever Hans as follows:

During the experiments, it emerged of course that the daily schooling of Clever Hans—in an attempt to “install in the horse’s mind the rudiments of human culture through long years of painstaking instruction” (Pfungst Reference Pfungst1911, 212)—had by no means resulted in the horse demonstrating autonomous cognitive ability. In fact: “After all this experimentation it was evident that the horse was unable to work alone, but was dependent upon certain stimuli from its environment” (ibid., 40). Experiments with blinders and other screening mechanisms had determined that “the horse was at a loss in the moment he was prevented from seeing the questioner; whereas his responses were nearly always correct when the experimenter was in sight” (ibid., 43). In his paper from 1907 titled “Clever Hans (The Horse of Mr. von Osten),” which is now considered a classic, Oskar Pfungst phrased it in an equally concise and clear way: “It is evident therefore, that the horse required certain visual stimuli or signs in order to make a correct response” (ibid., 43).Footnote ³

On October 20, 1904, in a meeting of the Psychologische Gesellschaft zu Berlin (Berlin Society of Psychology), the psychiatrist Albert Moll had already made a similar inference, which was based on his own and earlier studies of Clever Hans conducted in June 1903. These might have given the subsequent experiments by Stumpf and Pfungst basic methodological direction, but Pfungst’s book contains “no mention of Moll’s pertinent remarks on this subject” (Gundlach Reference Gundlach2006, 97).Footnote ⁴ Moll’s analysis of the horse at the time resulted in the conclusion that: “All tasks were brilliantly carried out, but only so long as Herr von Osten and his stablemen were present and aware of which tasks were being presented to the horses” (Moll Reference Moll1904, 369). By contrast, “all attempts miserably failed” as soon as Osten and the stablemen no longer knew the correct answer themselves (ibid.). For this reason, concluded Moll, “the horse by no means showed any kind of concept formation but rather unquestionably received assistance, that is, signals, to which it responded” (ibid.).

Moll thus considered the studied phenomenon to belong “not to the psychology of the animals, but to occultism,” because in his opinion it involved “a source of error that is familiar to anyone working in the sphere of occultism, namely that of minimal movements through which signals are given, such as so-called mind reading” (ibid.). Moll was one of the Fin de Siècle psychiatrists now known as “critical occultists” (Wolffram Reference Wolffram2009, 233) and, in the first known scientific study of Clever Hans, he was able to draw parallels to methods of occultism. This was due to the fact that he had already spent almost twenty years investigating, thanks to his interest in the acceptance of hypnotism by medical and scientific research, their spiritualist and occult thresholds in numerous parapsychological phenomena. He also worked with the notorious Munich doctor, parapsychologist, and hynotist Albert von Schrenck-Notzing in this context (see Sommer Reference Sommer2012).

The Clever Hans phenomenon

The psychologist Carl Stumpf described the baseline situation of his experimental research as follows:

Indeed, the experiment involving Clever Hans had evolved into an observation of the former elementary school teacher Wilhelm von Osten and a self-observation of the experimenter Oskar Pfungst. The theory of a transmission of communication symbols instead of actual learning achievement on the part of the horse primarily pertained to the visual channel. However, the question of how the transmission of certain visual stimuli could have hitherto remained concealed to all observers present initially remained unresolved. Reflecting on his experiments, Pfungst noted:

Therefore, the experimenter Oskar Pfungst directed his attention during the experimental situation from an observation of the horse to a study of the minimal movements of Wilhelm von Osten:

In order to prove the existence of certain “unintentional signs” (Stumpf Reference Stumpf1911C, 7), the head investigator Carl Stumpf altered the experimental setup to allow him to measure the precise point in time where these signs were transmitted:

As soon as the truly effective channel of communication between horse and human during the school lesson was identified, then the semantic level of the spoken questions and requests made of the horse was newly inferred, for they lost all meaning in terms of the horse’s reaction:

Pfungst’s conclusions thus radically shifted the perspective of the communication that was taking place: no longer was it Hans who was speaking, but rather Osten, whose body language was providing the decisive signals. Prior to Pfungst’s scientific dissection, Hans was seen as an actor providing answers to questions on an elementary school level. After his first experiments, Pfungst turned his attention to Osten as the questioner, accrediting the given answers to his “visual signs” and indicating that Hans was reacting in a stimulus-response scheme.

Pfungst’s explanations have already been criticized as “consistent use of the rhetorik of reversal” (Crist Reference Crist1997, 13), which might have led him to a “de facto exclusion of other explanatory options of Hans’s accomplishments” (ibid., 15). Instead of following this semiotic logic of the reversal of sender and receiver, which turned Clever Hans, the learning horse, into a mindless reactor, and Wilhelm von Osten, the teaching trainer, into an inconspicuous sender of certain stimuli, my argument focuses on the expansion of the channels of communication as a constitutive discourse strategy in the debates about animal psychology in the early twentieth century. As Warren Weaver stated, the form of the communication symbols’ transmission informs “the other levels” (Weaver Reference Weaver, Claude and Weaver1949, 6) – the semantic level and the problem of message efficacy. In the newly discovered channel of communication, the speaker of “hoof language” held the role of receptor who perceived “unintentional minimal movements” (Stumpf Reference Stumpf1911C, 5). Spoken language became noise, while inconspicuous movements transmitted information.

Even skeptical visitors could not avoid expecting a correct answer from Hans and thus inadvertently giving certain signs that contributed to the accuracy of his answers:

After it was determined that the communication perspective was actually reversed, with the experimental subject and the experimental object shifting within the very same experiment, the focus of Pfungst’s scientific study was transferred from the horse to its teacher with the aim of experimentally confirming the discovered channel of communication. However, after Carl Stumpf delivered his report about Clever Hans on December 9, 1904, declaring that he was unable to verify any cultural-technical education on the part of the horse, Osten aborted all further collaboration with the committee. Since this horse was no longer available for study, the next step for Oskar Pfungst lay in laboratory experiments.

Pfungst noticed “that thus far I have supposed the horse to be a never-failing mechanism and that I placed all errors to the account of the questioner” (ibid., 152). In order to more precisely research, in a laboratory setting, the effects of the questioner on the horse, in the subsequent experiments another test person now adopted the questioner role that had been originally assigned to Oskar Pfungst, while Pfungst himself took on that of the horse. While the respective test person was thinking of a certain number, Pfungst watched him and began, in an act of becoming-animal, to tap with the hand: “Then I would begin to tap—but in human fashion with my right hand, rather than with my foot—and continued until I believed that I had perceived a final signal” (ibid., 103). He noticed involuntary movements—similar to those already seen by Osten in twenty-three of twenty-five test persons—giving him a hint as to the number being thought. Therefore, during the experiment in the laboratory, as an “unintentional by-product of an unsuccessful attempt at real education” (ibid., 241), the symbolic character of involuntary movements supplanted elementary cultural-technical knowledge as the object of experimental interest. Henceforth, the laboratory experiments involved “the graphic registration of the minute involuntary movements which accompany the thought process” (Stumpf Reference Stumpf1911C, 11), for not until the expected number was arrived at did the movement take place. “Indeed, it was very difficult and in some cases almost impossible for those persons whom I had initiated into the secret, to inhibit them voluntarily” (Pfungst Reference Pfungst1911, 107). The device used for recording chronicled both the tapping signals and the head movements in three dimensions, as well as the breathing of the test person, that is, the person sending the signals (fig. 1).

Figure 1:

Oskar Pfungst, Diagram of the breathing curve of the questioner; the curves of his head movements in different directions; the reaction of the horse: the taps and the backstep; the lowest line indicating the time in fifth-seconds (Pfungst Reference Pfungst1907, 90).

As soon as the communication system, and thus the manner of transmission for the involuntary signs, had been identified, it was possible to experimentally prove that one cannot not communicate with a “signal animal” (Signaltier) (see Ettlinger Reference Ettlinger1913). The theory of transmitting communication symbols was thus expanded to include the “Clever Hans phenomenon”—as the process of inadvertently providing behavioral cues has been called since a conference of the New York Academy of Sciences in May 1980 (see Sebeok Reference Sebeok, Thomas and Rosenthal1981). It was there that Heini Hediger, a Swiss zoologist, established the following: “Communication, as it preoccupies us here in connection with the Clever Hans phenomenon, is not only a series of flow-processes between a chemical substance and a subject; it is a much more complex connection between the experimenter and the animal” (Hediger Reference Hediger1981, 3). Pfungst had already viewed the years-long education of Hans as a communication process of prompting characteristics, where the sharpening of the horse’s observation in particular showed that involuntary head movements, though at a variation of only 0.2 mm, could ultimately be perceived as signals through a learning process. Therefore, the results of the study by Pfungst and Stumpf opened up a new area of research in the field of psychology focused on ascertaining how “in some subtle, unintentional way experimenters do communicate their expectations to their human subjects, whose performance is then significantly altered” (Rosenthal Reference Rosenthal1965, XXV).

The question of the transmission channel in particular became highly relevant. The psychologist Robert Rosenthal, who released an English translation of the book by Oskar Pfungst in the United States in 1965, even elevated this aspect to the main research question:

When, in this respect, both the semantic plane and the effectiveness of a message are viewed as being subordinate to the message channel, then the technical problem of transmission of communication symbols appears to be the central issue of communicative systems.

The levels of communication are ultimately also the key to a new understanding of human-animal-relations, which Rosenthal—in view of Oskar Pfungst’s experiments with Clever Hans, resulting in an act of becoming-animal—had already established as being reciprocal in nature. Indeed, “not only could he read bodies,” as the science studies scholar Vinciane Despret noted about Clever Hans, he could also “make human bodies be moved and affected, and move and affect other beings and perform things without their owners’ knowledge” (Despret Reference Despret2004, 113). Moreover, this effect “could be experimentally studied”, with the result that “Hans could become a living apparatus that enabled the exploration of very complicated links between consciousness, affects and bodies” (ibid., 113–14). Therefore, from the vantage point of human-animal relations, the examination of levels of communication in the talking horse experiments facilitates the possibility of no longer studying actions and operations only in connection with humans, but also studying them as being reciprocally determined by complicated links between human and non-human bodies. This intervolved concept of agency provided a central point of departure for the establishment of the new research field of animal studies, to which reflection on the Clever Hans phenomenon made an important contribution (see Despret Reference Despret2015).

Berto

In his final report on Clever Hans, Carl Stumpf remarked that he would not be commenting on any future discussion about talking horses in the press:

This task was soon taken up by Karl Krall, a jeweler from Wuppertal who had sought out Wilhelm von Osten in May 1905, at a time when Clever Hans was no longer a big attraction after the release of the committee’s report. Following these initial experiments with Hans, and after Pfungst’s report was published in 1907, Krall began carrying out another comprehensive, protocolled, and witnessed series of experiments, in which Hans was fitted with a large blinder in order to rule out any optical signaling (fig. 2) and to exclude this channel of communication if at all possible.

Figure 2:

Karl Krall, Clever Hans with blinder (Krall Reference Krall1912, 6).

Krall repeated the experiments initiated by Stumpf’s committee because Osten felt that Stumpf and Pfungst had been the ones to “train Hans to respond to signs and thus spoil him for a long time” (Krall Reference Krall1912, 7). Over time, Krall succeeded in familiarizing Hans with the blinders, after which time he once again correctly mastered the required exercises. In this second series of experiments with the same horse, the focus was now once again on channels of communication, this time with the initial goal of ruling out any kind of visual communication. To this end, in addition to Hans’s cultural-technical abilities, his sensory perception was also tested again. Contrary to the Stumpf committee, Krall came to the conclusion that “a clear understanding between human and animal with regard to its perceptual state is possible” (ibid., 53). He then even taught Hans geometry, physics, and aesthetics, “in order to determine his own ‘aesthetic’ assessment of pictures and objects” (ibid., 59).

After the death of Wilhelm von Osten in 1909, ownership of the horse was transferred to Krall, who took Hans to Wuppertal so as to integrate him into his various projects with other animals, which were already taking place. These experiments eventually became quite famous as the “Horses of Elberfeld” mentioned by Warren Weaver. The previous year, Krall had already started a series of lessons with the two aforementioned horses named Muhamed and Zarif, which he protocolled in order to “provide a detailed development history of the lessons from the very beginning” (Krall Reference Krall1912, 90) and thus also to counter the research report drawn up by Oskar Pfungst. Instead of direct contact with the horses, here Krall employed media technology, for instance he developed “the option of successfully using the photograph in animal lessons” (ibid., 59) (fig. 3). In his lessons, Krall also implemented the cinematograph, the gramophone, and the telephone so as to avoid any direct contact between horse and experimenter if at all possible and to define only a singular mediatic channel of signal transmission. Though the horses utterly failed during the initial experiments with blinders, after a few weeks Muhamed and Zarif “became accustomed to the new experimental conditions and now performed the tasks in the same capacity before, but with blinders” (ibid., 97).

Figure 3:

Karl Krall, Clever Hans in front of a screen for slide projection (Krall Reference Krall1912, 58).

In the “tap-speaking exercises,” Krall experienced how “the horses reproduced the words spoken to them—even those learned orthographically—according to tone color” (Krall Reference Krall1912, 126). This circumstance was described by Krall as “striking proof for the independent thinking of the [equine] pupils, and for this reason any ‘rehearsal’ has been discontinued. Ever since, the horses have been spelling using their own ‘spelling rules’” (ibid., 127). On the basis of free orthography, they were able to independently articulate using both front hooves and a wooden board designed for tapping signs. For example, Zarif responded to this question posed by the groom: “‘Warum sagst du mir das denn nicht mit dem Mund?’ [Why don’t you say that to me with your mouth?]. Zarif: weil ig kein stime hbe [Because I don’t have a voice]” (ibid., 239). In fact, “Muhamed was always especially eager, and it frequently happened that he suddenly stopped spelling a word and tried to speak the sound. While practicing this without being prompted, he then suspended his attempts at speech and started spelling—fully of his own accord—the sentence: ig hb kein gud sdim [I have no good voice]” (ibid., 237–38) (fig. 4).

Figure 4:

Karl Krall, Zarif’s instruction in spelling (Krall Reference Krall1912, 182).

Eventually, Krall worked with a blind and anosmic horse by the name of Berto, which he saved from the butcher for the first two and a half years of his life. The idea was to use his successful schooling to put to rest, once and for all, the communication channel for transmitting optical signs, following the experiments with blinders (see Krall Reference Krall1913). There was no chalkboard in the stable from which Berto could learn his numbers. Instead, the numerical value was conveyed to the horse by tapping on his back.

After 14 days he had mastered the concept of numbers up to 9, as well as the three kinds of arithmetic (addition, subtraction and multiplication). On November 13, Berto could calculate two-digit numbers, with the right hoof tapping the first digit and the left hoof the tens. He was also able to recognize the numerals written on his fur (instead of being spoken) by way of touch due to their form, even two-digit numbers and simple arithmetic problems like 3x5, etc. The first instruction in spelling took place on January 29, 1913. Already on February 4, Berto articulated through hoofbeats several of the letters that had been taught to him without any help. On February 13, he spelled out—as had been frequently practiced with him—the answer to the question: ‘Wie heißt Du?’ [What is your name?]—his name without mistakes: b-e-r-t-o. (ibid., 12)

In addition to the witnesses of this schooling—namely, the psychologist Roberto Assagioli and the biologist William Mackenzie—the zoologist Hugo von Buttel-Reepen served as experimenter in December 1912. He ruled out optical signaling in his experiments and consistently received correct tapping signs from Berto, even when there was no groom nearby (see Berg Reference Berg2008, 85–86).

After conducting his experiments over several years with eleven horses, two donkeys, and one elephant (see Berg Reference Berg2008, 90; De Sio & Marazia Reference De Sio and Chantal2014, 95), Krall ultimately considered only two explanations for the communication achievements of his horses to be feasible: “either a ‘connex’ hitherto totally unknown to us, e.g., so-called telepathy, or autonomous thinking activity on the part of the horse” (Krall Reference Krall1912, 8). In 1912, Krall published his opinion in his 500-page book, Denkende Tiere (Thinking Animals), and founded the Gesellschaft für Tierpsychologie (Society for Animal Psychology). The society initially included around forty members (see Berg Reference Berg2008, 97–98) who considered the autonomous thinking hypothesis convincing. Heinrich Ernst Ziegler, a zoology professor at the Technical University of Stuttgart, was elected chairman, while Krall assumed the position of secretary. However, the outbreak of the First World War compelled Krall to discontinue his research and close his schooling stable in 1915. Contrary to a popular anecdote, his talking horses did not end up serving in the German Army on the battlefields of the First World War, but were actually given by Krall to a landowner he knew for use on the estate (ibid., 90).

After his horse school was closed down, Krall decided to set aside his research on “thinking animals” for the most part, and instead became more interested in the first of his two proposed explanations for the phenomenon of talking horses: telepathy. Meanwhile, the communication channel had recently been challenged by Stefan von Máday, who held a critical stance toward Krall and, in the year 1914, not only contested the independent articulation of the horses in his extensive “Entgegnung auf Kralls ‘Denkende Tiere’” (Objection to Krall’s “Thinking Animals”) but also disputed any kind of scientific competence on Krall’s part. Instead of offering further riposte to Máday, Krall chose rather to dedicate his efforts to seeking a further communication channel and, to this end, espoused one of Máday’s main arguments: “Not only did Krall subconsciously train the horses to recognize certain signs that to him—presumably—had remained unknown; he did not merely stay fully ignorant of what brought the horses to understand words and to solve math problems; he likewise did not realize that he had already had the thoughts of the horses before they did” (Máday Reference Máday1914, 450). After the First World War ended, Krall expounded upon this idea that a transmission of his thoughts to the horses must have taken place and created a research program to address it.

Krall’s interest in telepathy actually followed in this regard from his early approach to the work of Wilhelm von Osten and Clever Hans in searching for proof of thought transference between man and animal (see De Sio & Marazia Reference De Sio and Chantal2014, 96; Wolffram Reference Wolffram2009). In the 1920s, he founded the Krallsche Institut für Tierseelenkunde und Parapsychologische Forschungen (Krall Institute for Animal Psychology and Parapsychological Research) with a full laboratory in the south of Munich. This institute was supported by the founder of the Psychologische Gesellschaft (Society of Psychology) in Munich and renowned representative of early twentieth-century German parapsychology, Albert von Schrenck-Notzing (see Sommer Reference Sommer2012). In order to prove the existence of telepathic communication between man and animal, as appeared to manifest especially between dogs in their unspoken accordance with their human caregivers, Krall carried out complicated laboratory tests with the aim of intercepting any kind of “thought radiation” between man and dog (see De Sio & Marazia Reference De Sio and Chantal2014, 99). He published the first results of his research in 1927 and gave a lecture at the third Congrès International de Recherches Psychiques in Paris (see Krall Reference Krall1927).

Lady Wonder

In 1927, the same year that Krall’s parapsychological research was published, a two-year-old horse in Richmond, Virginia named Lady Wonder began learning to count and spell. The mare was given her own typewriter, which she used to type the letters “talking horse” using her muzzle, in order to answer in writing, in a self-referential way, the question of who is speaking. After correctly predicting the outcome of a boxing match between Jack Dempsey and Jack Sharkey, also in 1927, “Lady, the wonder horse of Richmond, Virginia” attracted national interest in the United States. The horse, claimed her owner Claudia Fonda, “could make predictions, solve simple arithmetical problems, answer questions aptly and intelligently, and do all this without verbal command. All that was needed was that the question be written down and shown to Mrs. Fonda” (Rhine & Rhine Reference Rhine and Rhine1929A, 452).

While Lady was paid for answering all kinds of questions, making predictions, and giving personal advice, which ensured the livelihood of her owner, the horse also became the subject of scientific interest, more than twenty years after Clever Hans. This scientific debate focused on the question of whether Lady—as her owner claimed—manifested a new level of communication that had not yet been addressed in the discussion of the talking horse phenomenon. This possibility added to the previous explanatory models of clever animal sensations—trained signaling or independent thinking and calculation ability—by including a third option, which had already been considered by Krall: mind reading.

Lady was promoted as a mind-reading horse. There was special equipment that allowed the horse to spell with her muzzle; she was able to solve simple math problems and even correctly predict the gender of unborn children. Yet in reply to a question posed by a visitor, “How do you like what you do?,” Lady—who at the late horse age of twenty-seven was still required to work and answer three questions for a dollar—gave a clear answer of “Don’t” (Truitt Reference Truitt1952, 21).

The prophesying and mind-reading horse had already been subjected to extensive studies in the winter of 1927–28 by the botanist Joseph Banks Rhine and his wife Louisa Ella Rhine, supported by William McDougall, a professor of psychology from 1927 to 1938 at Duke University in Durham, North Carolina. Their “Investigation of a Mind-Reading Horse” was published in the Journal of Abnormal and Social Psychology in 1929—the year of Karl Krall’s passing.Footnote ⁶ The Rhines’ studies made direct reference to Krall’s work (Rhine & Rhine Reference Rhine and Rhine1929A, 449–50) and formed an important point of departure for experiments with extrasensory perception (ESP) (see Rhine Reference Rhine1934). As of 1930, these experiments were conducted by J. B. Rhine as assistant for psychology at Duke University and as head of the first parapsychological research lab at a regular university department of psychology, the Department of Psychology at Duke University, established with the strong support of William McDougall, Rhine’s tutor and “the father of the professionalization of modern parapsychology” (Asprem Reference Asprem2010, 125). McDougall lent an academic basis to Krall’s similar project by enabling the creation of a research lab in a regular university department of psychology.

It should be noted that the testing of this talking horse was very important for the creation of this lab, especially because the aspect of parapsychological factors in human-animal communication was introduced by Karl Krall, who possessed no scientific reputation whatsoever. The research question posed by Rhine was therefore adapted to the three hypotheses for explaining the performance of the horses: Could the successful exclusion of signaling be verified while Lady was calculating, predicting, and talking, and could the already known sensory channels for signaling be eliminated?

After a first test series, Rhine concluded: “There is left then, only the telepathic explanation, the transference of mental influence by an unknown process” (Rhine & Rhine Reference Rhine and Rhine1929A, 463). The results “appear to show that Lady does not have a ‘working-knowledge’ of the alphabet, by which most of her work is done, and that in some manner she is directed to the blocks by an external agency” (ibid., 464). In exuberant response to these text results, Rhine wrote a letter to Mrs. Fonda “stating that the animal was ‘the greatest thing since radio’” (Christopher Reference Christopher1970, 43).

In a second test series carried out in December 1928, Joseph B. Rhine and Louisa E. Rhine determined that this external agency could be named because the horse could only read his mind when her owner, Mrs. Fonda, was standing nearby. They concluded that the knowledge of someone present was necessary for successful performance and concluded again that this was a case of mind reading. In a second report, which ended and closed the analysis of Lady, he came to the conclusion “that the telepathic ability we earlier found the horse to possess has been now almost if not entirely lost and that Lady has become merely a trained animal conditioned to a system of signals made up of indicative body movements, voice inflections, whip movements” (Rhine & Rhine Reference Rhine and Rhine1929B, 291). The whole thing was a charlatan trick, he concluded: “When he stood behind F [Mrs. Fonda] and wrote the number on a pad as he had once done with excellent results, there was now complete failure” (ibid., 289).

In the 1950s, when Lady was still reading minds and making prophecies, a professional magician, Milbourne Christopher, visited the horse and had to write a number between one and nine, which the horse was meant to guess. After Claudia Fonda gave him a long pencil and a pad, he had to stand across the room and write any number: “I wrote a 2, which Lady flipped up, then a 1 which Lady gave as 9. I wrote the 2 as anyone would, but when I wrote a 1, I went through the motions of writing a 9 but only touched my pencil to the paper for the downstroke” (Christopher Reference Christopher1970, 44). Since Lady guessed the number nine, he had a clear indication how the trick worked, because Fonda was pencil-reading by observing the motions of the long end of a pencil, and after that the horse guessed correctly what the person had written down. Even though the analysis of how Claudia Fonda and Lady communicated had not yet been finished, the mind-reading performances by the horse had been unmasked, for they were based on a system of signals made up of indicative body movements, voice inflections, and whip movements.