Duke University in 1933 with Zener cards. Certain symbols that were placed on the cards and sealed in an envelope, and she was asked to guess their contents. She performed poorly and later criticized the tests by claiming the cards lacked a psychic energy called "energy stimulus" and that she could not perform clairvoyance to order. The parapsychologist Samuel Soal and his colleagues tested Garrett in May 1937. Most of the experiments were carried out in the Psychological Laboratory at University College London. A total of over 12,000 guesses were recorded but Garrett failed to produce above chance level. In his report Soal wrote "In the case of Mrs. Eileen Garrett we fail to find the slightest confirmation of J. B. Rhine's remarkable claims relating to her alleged powers of extra-sensory perception. Not only did she fail when I took charge of the experiments, but she failed equally when four other carefully trained experimenters took my place." The parapsychology experiments at Duke evoked much criticism from academics and others who challenged the concepts and evidence of ESP. A number of psychological departments attempted to repeat Rhine's experiments with failure. W. S. Cox (1936) from Princeton University with 132 subjects produced 25,064 trials in a playing card ESP experiment. Cox concluded "There is no evidence of extrasensory perception either in the 'average man' or of the group investigated or in any particular individual of that group. The discrepancy between these results and those obtained by Rhine is due either to uncontrollable factors in experimental procedure or to the difference in the subjects." Four other psychological departments failed to replicate Rhine's results. After thousands of card runs, James Charles Crumbaugh failed to duplicate the results of Rhine. In 1938, the psychologist Joseph Jastrow wrote that much of the evidence for extrasensory perception collected by Rhine and other parapsychologists was anecdotal, biased, dubious and the result of "faulty observation and familiar human frailties". Rhine's experiments were discredited due to the discovery that sensory leakage or cheating could account for all his results such as the subject being able to read the symbols from the back of the cards and being able to see and hear the experimenter to note subtle clues. Illusionist Milbourne Christopher wrote years later that he felt "there are at least a dozen ways a subject who wished to cheat under the conditions Rhine described could deceive the investigator". When