Zener Cards: what they are and why they do not demonstrate cases of telepathy

Zener cards have been widely used to try to demonstrate telepathic powers.

Is there such a thing as telepathy and clairvoyance? These two questions are very old, and there are many people who have claimed to have psychic powers, although when it comes to proving it, they have not been able to show it.

Faced with these questions, as surprising as it may seem, there are those who have tried to study them in a scientific way, building instruments with the intention of demonstrating whether a person was able to read the mind of another.

Among these instruments, we have the famous Zener cardsThese cards contain drawings that must be guessed or transmitted mentally to other people. Let's discover the mysterious world of extrasensory research with these cards.

What are Zener cards?

Zener cards are cards designed to be used in extrasensory perception or clairvoyance experiments. They were created in the early 1930s by Karl Zener (1903-1964), a psychologist of perception, and his botanist colleague J.B. Rhine (1895-1980), founder of parapsychology as a branch of psychology. These letters are one of the first purportedly "scientific" instruments for the objective study of supernatural powers, although their pseudo-scientific characteralthough their pseudoscientific character has generated much controversy.

A normal deck of Zener cards consists of 25 cards, 5 for each of the 5 symbols that can be found on them: square (□), circle (○), star (☆), cross (+) and wavy lines (⌇⌇⌇⌇). Apparently, these symbols were chosen because they were easy to represent mentally and, for this reason, Zener and Rhine deduced that they were easier to transmit telepathically. Thus, it was considered that these cards were ideal to be able to perform scientific experiments in which statistical methods of real science could be applied.

Experimentation with these charts

Testing the telekinetic and clairvoyant abilities of people can be done in a variety of ways, but, in essence, the method is usually the same. The use of these cards is intended to find out if a person is able to read the mind of another person who is looking at the cards. A fairly classic example to demonstrate someone's telekinetic ability is the one we are going to see below.

Two people participate in the experiment as subjects, while an experimenter is recording any phenomena that may occur. during the conduct of the study. These two people are an "agent" or "sender" and the other is the "perceiver" or "receiver". The idea is that, if the perceiver has psychic powers, he or she will be able to read the agent's mind.

The two people are seated at two ends of a table, preferably separated by a screen or opaque screen, since the ideal is to prevent the perceiver from reading the agent's mind.Ideally, the two subjects should not be able to see each other. The person who will act as the agent will receive a deck of 25 Zener cards, which he will have to pick up one by one. He will look at each card for about 5 to 10 seconds, trying to think only about what he is seeing. The other person, who is supposed to be the perceiver, will write down on a piece of paper the symbols he thinks he is reading in the agent's mind.

Once all 25 cards in the deck have been uncovered and read, the experimenter will compare in what order the symbols in the Zener deck have been presented and which symbols the perceiver has picked up. He will statistically analyze both lists, to see if there has been a real case of telekinesis or if the supposed perceiver lacks any psychic power.

According to the clairvoyant community itself, this experiment should be repeated for several days, at least 5 times.at least 5 times. Each day the same experiment will be performed, in which 25 Zener cards will be uncovered and the extent to which the perceiver is capable of mentally reading what the agent sees will be tested. Once the coincidences have been analyzed and studied, it will be possible to clarify whether or not there really is extrasensory communication.

As the decks of Zener cards are usually of 25 cards, 5 for each of the 5 symbols, in case of not possessing any psychic power, it is not possible to hit more than 20% of cards, that is to say, only 5. In principle, if this percentage of correct cards is exceeded, according to the extrasensory experimenters themselves, randomness would be overcome and we would be talking about a case of true mind reading.

Criticism of Zener and Rhine

Although, without a doubt, Zener cards are an interesting tool, their research has criticisms. They both claimed to have found cases of people who could read other people's minds, but when their same experiments were replicated, this evidence vanished.. Even so, the New Age community and other followers of the mystical have considered the "findings" of these two researchers as firm proofs of the existence of psychic powers.

The first criticism of experiments with Zener cards is the fact that there is a risk that the cards are always presented in the same order, causing the perceiver to learn them unconsciously and, sooner or later, to guess the cards. It would not be a matter of mind reading or telekinesis, but of memorization. It should also be said that Rhine tried to avoid this phenomenon and in his experiments he chose to shuffle the cards with a special machine.

John Sladek, science fiction writer, made his disbelief known in the book The New Apocrypha that two supposedly rigorous researchers had opted for cards as a tool to test the existence of extrasensory powers. Cards have been used by magicians and gamblers in casinos for a long time, having their own methods to trick them and know, without the need to uncover them, what is on the other side.

In case the experiment is done without screens or anything that prevents the vision between the two subjects, it can happen that the perceiver ends up learning what is behind the card just by seeing a wrinkled corner or a characteristic pattern of the card on its side without drawing. It may seem far-fetched, but in this same situation the agent person can tell what the agent sees not by reading her mind, but by reading her eyes. The drawing she is seeing can be reflected in the cornea, making the perceiver know what the drawing is.

Finally, we have the case of nonverbal language. If both subjects are seeing each other and know each other a little, they are likely to communicate without the need to speak.. It is by means of unconscious microexpressions that an agent can indicate to the perceiver whether or not he is guessing the symbol he is indicating to the experimenter. That is, if the perceiver says "star" and the agent makes a small gesture of displeasure, the perceiver will assume that he has made a mistake and change his response.

An example of microexpression reading can be found in the 2016 case investigated by Massimo Polidoro. Polidoro tested a mother and daughter who claimed to have psychic powers, with a success rate of over 90% using Zener cards. However, the researcher placed restrictions so that they could not see each other's faces, which brought their success rate down to simple chance. Mother and daughter were not cheating, but they knew each other so well that they could communicate unconsciously through small gestures.

What are the chances of getting the whole deck right?

Rigorously scientific evidence that clairvoyance and telekinesis exist is conspicuous by its absence. Zener cards, used in experiments in which the two experimental subjects do not see each other and the deck is heavily shuffled, are a good method of demonstrating just the opposite of what Rhine and Zener wanted to demonstratethat extrasensory powers, or at least mind reading, most likely do not exist.

The results of the tests that have been done with these cards follow the normal distribution, with the percentage of success being no more than 20%, which corresponds, as we have said, to guessing only 5 cards out of a deck of 25 cards.. About 79% of people will guess between 3 and 7 cards. Guessing more than 5 is possible but statistically unlikely. Let's look at the chances of guessing more than that number of cards below.

The percentage of guessing 8 or more cards correctly is less than 10.9%. The chances of getting 15 correct answers is about 1 in 90,000. Guessing 20 to 24 has a probability of about 1 in 5,000,000,000,000,000 and guessing absolutely all of them has a probability of about 1 in 300,000,000,000,000,000,000,000,000. has a probability of 1 in 300,000,000,000,000,000,000,000,000,000.

Taking into account these mathematically calculated possibilities, which correspond to what has been observed in real experiments with Zener cards, it is to be expected from any rigorous scientific research, the expected outcome of any rigorous scientific investigation would be to apply Ockham's razor and accept the null hypothesis for null or negative results. for null or negative results. That is, that one cannot read the mind of the person who is looking at one of the many Zener cards. However, parapsychology is not a science, and much less will it use the scientific method per se.

This pseudoscience has invented ad hoc explanations to explain and deny the failure of its investigations, some of them truly motley, such as that there are people who have "psychic anti-powers" and reduce the extrasensory abilities of those who do have them. Many parapsychologists assure that it is to be expected that 99% of the subjects do not have psychic powers, but 1% do have them and can "prove" it. But the curious thing is that, to this day, they have not demonstrated anything.

Bibliographical references:

• Rhine, J. B. (1934). Extra-Sensory Perception. Boston, MA, US: Bruce Humphries.
• Rhine, J. B. (1937). New Frontiers of the Mind. New York, NY, US.
• Mauskopf, S. H., & McVaugh, M. R. (1980). The Elusive Science: Origins of Experimental Psychical Research. Baltimore, ML, US: Johns Hopkins University Press.
• Polidoro, M. (2003). Secrets of the Psychics. Prometheus Books.