Telepathy: Extrasensory Perception
or Population Stereotypes?

At the end of the 19th century, researchers from Britain’s Society for Psychical Research became interested in extrasensory perception (ESP), particularly telepathy—the hypothesized ability to perceive another person’s thoughts or feelings. They learned of the Creery sisters, five siblings from a small town who claimed they could transmit and receive thoughts among themselves, and decided to test their abilities under controlled conditions.

The experiments were straightforward: one sister would focus on an object, number, or word, while another, in a separate room, attempted to "receive" the thought and identify it.  The sisters demonstrated a striking level of accuracy, frequently making correct identifications. Their apparent success sparked enthusiasm within the scientific community—until the case took an unexpected turn when the sisters later admitted to cheating in some of the experiments. Despite the deception, this case became one of the earliest and most notable studies in what would later be known as the field of psychology, influencing future research methodologies. This episode serves as a reminder of the importance of skepticism in such studies and the need for rigorous and well-controlled experimental design.

Extrasensory perception (ESP) refers to alleged processes of information transfer that cannot be explained by known physical or biological mechanisms. Telepathy, one of the most widely recognized ESP concepts, is classified as a pseudoscientific phenomenon within the field of parapsychology, a discipline that seeks to study the possibility of extrasensory perception using scientific methods. However, no conclusive evidence has ever substantiated the existence of telepathy. From a neurological perspective, telepathy is considered impossible, as the brain functions through electrical signals and chemical neurotransmitters within neural networks - none of which leave the body. According to current scientific understanding, no known mechanism allows thoughts to be transmitted beyond the body.

Unusual processes of information or energy transfer that cannot be explained by known physical or biological mechanisms. Card experiment for testing extrasensory perception, 1940 | Source: Francis Wickware, Wikimedia

The Large Audience Effect

Performers who identify as "mentalists" or mind illusionists often attempt to create the impression that they possess extrasensory perception (ESP). In performances held before large audiences, they may conduct a so-called "telepathic" experiment, asking the audience to guess a number they are supposedly thinking of—usually between one and ten. The performer presents it as a probability game, suggesting that if 10% of the audience guesses the number correctly, it would be expected by chance. However, if more than 10% succeed, it is implied that the message has been transmitted telepathically. The audience is then asked to raise their hands if they thought of the number seven—and in a large crowd, over 30% may do so. Does this prove telepathic communication? Not necessarily

The psychological explanation for this surprising result lies in a phenomenon known as population stereotypes. When asked to choose a number at random, we tend to assume that our selections will be evenly distributed across all available options. However, in reality, human thought patterns are not truly random—certain numbers are chosen far more frequently than others, even when the selection comes from a broad range of choices.

This pattern appears in similar tasks with slight variations, such as attempts to "transmit" a specific shape or color telepathically. When asked to pick a random color, people disproportionately choose blue. The strong tendency to select seven as a number and blue as a color is so consistent that it has been named the Blue-Seven Phenomenon.

 The apparent success of extrasensory perception can be explained by the phenomenon of population stereotypes. "Mind reading" during a stage performance, 1900 | Source: Library of Congress.

?Magic Numbers

Why is the number seven more commonly chosen over, say, one, five, or ten? While the exact reason remains unclear, several explanations have been proposed. One possibility is that seven stands out, being perceived as unique and intriguing because it is a prime number, unlike more "obvious" choices at the extremes or center of the range, such as one, five, or ten. Additionally, cultural influences may play a role—seven appears frequently in religious and historical contexts, from the seven deadly sins in Christianity to the seven days of the week and even the seven dwarfs in Snow White.In many cultures, it is also considered a lucky number, which may make it more appealing.

As a result, mentalist "mind-reading" tricks work particularly well in large audiences because responses tend to cluster in predictable ways. Many people share similar cultural and cognitive associations with certain numbers, words, or images, making some choices more mentally available, “popping into our heads" more frequently than others.

It is important to note that the population stereotype effect does not claim to explain anomalous perception phenomena such as telepathy, nor does it necessarily disprove extrasensory perception. Rather, it demonstrates how predictable thought patterns can be exploited to create the illusion of mind-reading, even when no real telepathic ability is at play.

Blocking external sensory input to induce sensory deprivation. A woman participates in a Ganzfeld experiment, a method used in ESP research | Source: Jeremy Walker / Science Photo Library.

 Perspectives for the Future

Research into extrasensory perception continues to this day, despite widespread skepticism and methodological challenges. One of the most common experiments in the field is the Ganzfeld experiment, in which participants' eyes and ears are covered to block external sensory input, creating a state of sensory deprivation.   After a few minutes, participants often report visual and auditory hallucinations. In attempts to study telepathy, for instance,a message is "transmitted" to the participant, and researchers assess whether their hallucinations resemble the intended message.

Some researchers believe that such experiments provide evidence for the existence of extrasensory perception, while others argue that even if certain studies report some positive findings, these effects are small and difficult to replicate. Some suggest that the use of conventional neuroscience models, which may not adequately capture the complexities of ESP, is responsible for the conflicting evidence, arguing that new theoretical frameworks are needed for studying it effectively. Additionally, many studies involve participants with no emotional connection to one another, performing tasks that have little personal significance. However, some research suggests that extraordinary shared experiences, such as perceived telepathic communication, are often deeply personal and emotionally charged, and are more likely to occur in emotionally close individuals. People with strong emotional bonds, such as identical twins, are more likely to report such experiences, raising questions about the role of psychological and emotional factors in the perception of ESP phenomena.

Despite the skepticism surrounding ESP, open-minded research remains valuable—especially with the use of innovative methodologies and rigorously controlled experimental conditions.