Extrasensory perception (ESP) is the apparent ability to acquire information by paranormal means independent of any known physical senses or deduction from previous experience. The term was coined by Duke University researcher J. B. Rhine to denote psychic abilities such as telepathy, the sensing of thoughts or feelings without help from the 5 known senses, precognition, the knowledge of future events, and clairvoyance, the awareness of people, objects or events without the help of the 5 known senses. ESP is also sometimes casually referred to as a sixth sense, gut instinct, a hunch, a weird vibe or an intuition. The term implies sources of information currently unexplained by science. Popular belief in ESP is widespread, but sceptics are still not persuaded that there truly is a sixth sense because of the lack of reliable theories and information.
As you progress, your performance should improve greatly. If you get good enough, the computer shows how likely it would be to achieve your score by chance alone. For example, the chance of picking 8 correct cards in 20 trials is only 1 in 1247.
Zener cards are cards used to conduct experiments for extra-sensory perception (ESP), most often clairvoyance. Perceptual psychologist Karl Zener designed the cards in the early 1930s for experiments conducted with his colleague, parapsychologist J. B. Rhine. There are just five different Zener cards: a hollow circle (one curve), a Greek cross (two lines), three vertical wavy lines (or "waves"), a hollow square (four lines), and a hollow five-pointed star. There are 25 cards in a pack, five of each design.
When Zener cards were first used, they were made out of a fairly thin translucent white paper. Several subjects or groups of subjects scored very highly until it was discovered that they had often been able to see the symbols through the backs of the cards.
In a test for clairvoyance, the person conducting the test (the experimenter) picks up a card in a shuffled pack, observes the symbol on the card, and records the answer of the person being tested for ESP (the subject), who must correctly determine which of the five designs is on the card in question. The experimenter continues until all the cards in the pack have been tested.
Third parties may oversee or videotape an experiment to make sure it is conducted fairly. While it is especially important to ensure that the subject cannot see any cards and does not receive any vocal or visual cues from the experimenter, other methods of cheating are possible. To this end, physical separators may be placed between the experimenter and the subject. As with other ESP tests, experiments with Zener cards have used elaborate methods to keep the subject from seeing the cards or the experimenter, sometimes placing the subject in a separate room.
If the subject is informed during the test that specific guesses were correct or incorrect, card counting can increase their accuracy; also, poor shuffling methods can make the order of cards in the deck easier to predict. In his experiments, Rhine first shuffled the cards by hand but later decided to use a machine for shuffling.
On line variations of Zener card tests currently exist on the internet. If properly constructed, tests of this nature can circumvent the issues of bias and cheating common to standard Zener card tests. One such on line system, the Anima Project , gathers user results into a master database which is then analysed using a variety of statistical techniques.
Although Zener cards are usually used to test for clairvoyance, they may also be used to test for telepathy, in which case one subject will draw a card and attempt to mentally project the image on it to the mind of another subject. Here, the statistical tendency of the receiver to report a specific design must be taken into account — for example, they might tend to report receiving an image of a square more than other images — so the deck used must contain an equal number of cards of each design.
If the null-hypothesis (no psychic ability) is assumed and each card selected for testing is chosen in a truly random fashion, a user's success ratio is expected to approach 20% (1 hit per 5 trials) as their number of trials increases. The further the observed scenario is from the expected scenario, the more cause for believing the null-hypothesis is not true (the results are not simply due to chance).
The existence of ESP abilities is highly controversial, and no scientifically conclusive demonstrations of the existence of ESP have been given. Parapsychology explores this possibility, and some experiments such as the ganzfeld have been suggested as good evidence of ESP. The existence of ESP is not generally accepted within the scientific community.