anywhere from 8.9 to 9.9 of the 25 cards correctly. This is a significant amount over the 5 out of 25 probability from chance. The only problem with this test is that in order to get results above pure chance the participant must guess better than 1 out of 5. For this experiment to give more concrete evidence of clairvoyance a large sample size for the participant to guess from would be necessary as this would create a larger difference between chance and clairvoyance making the data much more concise. There was also a sort of “learning curve” with the participants whenever the testing setup was changed. When first trying the new testing setup the participant would perform very poorly, improving over time until plateauing just over chance probability. This improvement over time shows that there may have been something about how they were being tested that can be learned or practiced knowing how to “guess” better, but only to a certain extent. If it were truly down to clairvoyance, then the results should be the same regardless of how the test were administered. Another flaw with how the tests were administered is how many trials were performed. While a few thousand tests may seem like a lot, a few years later another set of tests were performed with a much larger sample size of over 100,000.
Samuel Soal aimed to perform similar tests to the ones performed by J.B. Rhine as addressed in the previous paragraph. In the 1930s, he tried his best to replicate the results that were achieved with little success. He used the same set of 25 Zener cards and had 160 subjects perform the tests over several years. In the end he had recorded 128,350 guesses. The average that the card was guessed correctly was between 5 and 5.001, what was to be expected purely by chance. This sample size dwarfed that of Rhine and showed results that were in line with the expectations of our understanding of probability. Soal’s results completely disproved the results that Rhine had collected and published, and he was known in the scientific community as being one of Rhine’s biggest critics. However, Soal’s later work did not hold as much merit