Whether in ancient or in contemporary times, dreams are a mystery of the mind that everyone has experienced. Quite likely, most individuals have also pondered the meaning of their dreams.
One myth about the human brain is the claim that humans use only about 10 percent of their brain capacity. Medical doctors and psychologists insist that the statement is not supported by any scientific evidence.
Memory is the ability to retain and to recall personal experiences, information, and various skills and habits. While memory is easy to define, there is no agreement among researchers to explain how it works, and scientists have not yet established a model for the actual mechanics of memory that is consistent with the subjective nature of consciousness.
Professor Nathaniel Kleitman (1895–1999), a University of Chicago physiologist and co-conductor of the Kleitman-Dement dream research findings, is known as the father of modern sleep research. Kleitman said that dreams are hard to remember because the higher centers of the brain are deactivated during sleep—or are operating at a much slower pace than during hours of consciousness.
Dr. John Lorber (1915–1996), neurology professor at the University of Sheffield in the United Kingdom, recalled the time in the 1970s when the campus doctor asked him to examine a student whose head was a bit larger than normal.
A phobia is a persistent irrational fear that causes a person to feel extreme anxiety. When people have a phobic reaction to a situation, a condition, or a thing, they may experience sweating, increased heart rate, difficulty in breathing, and an overwhelming desire to run away.
A placebo is a tablet or a liquid with no medical qualities that physicians will give to calm the anxieties of patients who insist upon receiving drugs when none are deemed necessary. In other instances, pharmacologists who wish to test the effects of a new drug may give placebos to a control group and the real drug to another as a method of gaining a more accurate determination of the effectiveness of the drug under development.
An altered state of consciousness is a brain state wherein one loses the sense of identity with one's body or with one's normal sense perceptions. A person may enter an altered state of consciousness through such things as sensory deprivation or overload, neurochemical imbalance, fever, or trauma.
Extrasensory perception—ESP—is defined by parapsychologists as the acquisition by a human or animal mind of information it could not have received by normal, sensory means. Some researchers, however, take issue with the term "extrasensory perception." They protest that the phenomena may not be "perception" at all, as the receiver of this information does not know if the knowledge is right or wrong when he or she first perceives it.
An opinion poll conducted in Canada in October 2002 discovered that 40 percent of Canadians believe that certain individuals have extrasensory perception that enable them to see into the future. The poll also revealed that 30 percent of the respondents had consulted with a medium, a psychic, or an astrologer.
In their biennial report on the state of science understanding released in April 2002, the National Science Foundation found that 60 percent of adults in the United States agreed or strongly agreed that some people possess psychic powers or extrasensory perception (ESP). In June 2002, the Consumer Analysis Group conducted the most extensive survey ever done in the United Kingdom and revealed that 67 percent of adults believed in psychic powers.