The mind is not a physical entity, therefore it cannot be defined scientifically. The mind is generally considered to be the awareness of consciousness and the manifestations of thought, perception, emotion, determination, memory, and imagination that takes place within the brain. The human brain has three principal structures. The cerebrum, which is the biggest structure, is the center for intelligence and reasoning. The cerebellum, at the back of the skull, is involved in keeping balance and posture. The medulla, which is a stem leading to the spinal column, handles involuntary functions such as respiration.
The functionality of the brain is hard to study because it is a complex dynamic system. It is theorized that memories in the brain are stored as chemical structures and as a neural network, with the information represented as a specific set of synaptic connections. The operation of the brain depends not only on the electrical signals passed by the neurons, but also on the influence of various neurotransmitting substances whose presence or absence can cause sleepiness, depression or even schizophrenia. Experiments have shown that rats kept in a complex, challenging environment develop more neural connections in the cerebral cortex than those kept in dull and uninteresting environments. Experiments have also shown that untrained fish that are fed the brains of fish trained to avoid the dark, also avoid the dark. It is possible that there are many learning mechanisms, each adapted to the brain structure of the learner.
The cerebrum consists of two cerebral hemispheres connected by the corpus callosum, which makes it possible for our left side to know what the right side is doing. This is necessary because most of the sensory organs and motor control on the left side of the body are connected to the right hemisphere, and vice-versa. The only exception seems to be the sense of smell where the right and left nostril sensors are connected to the right and left hemispheres, respectively. The cerebrum has four distinct sections called the frontal, parietal, temporal, and occipital lobes. The frontal lobe plays a part in planning, judgment, language, memory, motor function, problem solving, sexual behaviour, socialization and spontaneity. The parietal lobe integrates sensory information and helps in the manipulation of objects. The temporal lobe is involved in spatial perception and auditory processing. The occipital lobe is the visual processing center. The cells in this lobe are arranged as a spatial map of the retinal field. Extensive psychological and physiological studies of normal people using imaging technologies and studies of people who have had injuries or suffered strokes in portions of their brain have shown that verbal ability (writing, speaking) and logical ability (arithmetic) are dominant in the left side of the brain, even for left-handed people. Whereas the right side of the brain is responsible for three-dimensional vision, pattern recognition (including recognition of faces), musical ability and holistic reasoning. Thus, there is the popular notion that a "rational" person is a "left-brain" person, whereas an "intuitive" person relies mostly on the right part of the brain.
What is important for us is not the biological structure of the brain, but rather what it is capable of doing. The totality of the conscious and unconscious functionality of the brain and central nervous system is called the mind and, sometimes, the psyche.
The mind is a storehouse of information. Some of this information is learned and some of it is carried as part of our genetic constitution. Our senses provide input that is analyzed, interpreted, and stored in our mind. Sometimes the input from the senses conflicts with what the mind knows to be true. These illusions are common with sight. If we look at a grid of white lines on a black background, the eye perceives gray spots at the intersections of the horizontal and the vertical lines. Straight parallel lines drawn equidistant to a point from which straight lines radiate will be seem to curve away from the point. On the stage a magician says, "The hand is quicker than the eye", and proceeds to apparently pull cards out of thin air. Indeed, an image in the eye persists for about 1/30th of a second leading to many illusions. Still pictures projected at thirty frames per second are perceived as continuous motion and provide the foundation of the television and the movie industry.
It is necessary to understand the limitations of our senses so that our mind will not be fooled, and it is necessary to understand the limitations of our mind so that we know when to trust our senses.
The two senses that we use the most are sight and sound. Touch is used in familiar situations. Smell is used in close quarters, and taste is used when we eat. Eyeglasses may influence what we see. Most glasses will filter out some part of the visible spectrum, specially tinted glasses or sunglasses. Yellow sunglasses, for instance, make it difficult or impossible to distinguish blue from green highway signs. White flowers and yellow flowers cannot be differentiated either. Wearing this type of glasses is like getting a case of color blindness. Glasses also create distortions or reflections, and they can fog, obscuring visibility. Noisy environments can impair hearing. Hearing aids, which sometimes become necessary for older people, do not yet have the ability to focus on the sounds that are of interest to their users.
Memory is essential to our survival. Memory encodes our perceptions through the various senses. Recall is the ability to remember an event without any aids. Recognition is being able to remember something from the past when perceived again. Recollection involves remembering with the aid of stimuli that serve as clues. Looking at a pressed flower, for example, may bring memories of the events that happened when we put the flower between the pages of a book. Skills acquired through conscious effort, and repeated frequently, eventually become automatic so that it is not necessary to "remember" how to drive a car or where the letters of a keyboard are located. Memory is volatile and can be manipulated. It is not unusual for a person to think that he or she remembers something when authoritative individuals, such as psychiatrists, police detectives, or hypnotists, pressure someone into admitting knowledge about incidents that the person may not have experienced. The person's imagination creates images that persist and can be remembered as if they had actually happened.
Clear your mind and try not to think of a circus elephant. Are you visualizing a circus elephant anyway? If you imagine that you ride on top of the elephant can you see the ground? Do you feel the wobble as it walks? Mental simulations such as this, can create mental images that can be reinforced by adding realistic detail, such as times, dates, smells, etc. There may come a time when some individuals may actually think that they remember riding a circus elephant even if they never have. Techniques like these can be used to plant memories or to modify behavior. False memories and specific behavior may be induced in a person subjected to stress, sleep deprivation, or other stimuli that may trigger Pavlovian responses.
You are touring a country where you have never been before, and all of a sudden, the place where you are seems familiar, as if you had been here before. That is déjà vu. What triggers these memory episodes? Was it a childhood experience? Was it a magazine that you read? Was it a movie that you saw? The answers can never be determined externally. Your memories are only yours and not shared by anyone else. Psychologists have set up experiments where they position several witnesses in a location where an incident is staged. Then they ask the witnesses to report what they saw. Witnesses frequently make mistakes in the events and the sequences of events that they report. If the interrogators provide the witnesses with photographs of events that actually happened and events that were staged at a different time, sometimes the witnesses will say that they "remember" events that they did not actually see. Memory decays with time. The longer the time elapsed between an event and when we recall it, the less vivid and less detail that we will remember.
Hallucinogens, intoxicants, and other drugs can play havoc with memory and other mental functions. It is amazing to see someone do something outrageous while intoxicated and the next day act as if nothing had happened. Such is human memory! Deprivation of sleep, food, or water can cause hallucinations and altered perceptions. So can illnesses accompanied by high fevers. Moods that we feel such as frustration, anger, fear, are generally mediated by the mind. However, there are reactions that are unexpected even to us. These are the instinctive reactions built into our organism. We may jump at the sight of a spider or snake and stomp our feet. Fear is known to cause lack of control of the bowels and the erection of the hair at the nape of the neck. We vomit at the taste of something awful or at a gory sight. These are instinctive reactions that have allowed our species to survive. We do not have to think about them. We cannot even predict the situations that may trigger them.
There are many types of heuristics employed by the mind as shortcuts for assessing information quickly. Several mechanisms of social cognition enable us to make inferences from social information. If you meet a used car salesman at a party, you may immediately feel distrust because the stereotype of used car salesmen is that they lie and cheat. The pattern-matching ability of the mind is exceptional, but it tends to perceive what it is seeking. If you are hungry, many things will remind you of food. If you are looking for a face you will find one, whether it is in the formations of the clouds, the print of a flowery towel, or the surface of the moon. In an experiment, horoscopes were distributed to persons attending a class. The students were told that each horoscope had been made especially for each of them, and they were asked to rate its correctness. Most participants agreed that the horoscopes were fairly accurate for each of them. The students were then asked to pass their horoscope to the person next to them. They were amazed to find out that all of them had received exactly the same horoscope. This willingness to apply a general description with no specific data to one's own life is called "subjective validation" and it results from our search for relevance in the information that we process.
We spend approximately one third of our life sleeping. What does the mind do during this time? Why do we need so much sleep? Encephalographic (EEG) research has shown three distinct patterns of electrical activity of the mind: awake, asleep, and dreaming. Studies of sleeping subjects have identified different stages of sleep. Dreaming occurs only during some of these stages, and there is evidence to believe that other mammals besides man dream. Sleep refreshes the organism. Dreaming is thought to be caused by perceptions and ideas to which a person is exposed during waking hours. Some people use a technique of "problem immersion", which is to study a problem and its possible solutions in excruciating detail for several days, to force the dreaming mind to examine solutions that may not be apparent to the conscious mind. Dreaming seems to take disconnected ideas and permute them regardless of whether it is logical to do so or not. Feasible solutions are sometimes obtained. Many scientists have reported that their great ideas have been conceived in dreams. Inspiration and creativity may result when these processes occur while we are awake. Some dreams may be caused by fears or other needs. You may dream that your arm has been infested by bees that are making holes in it, only to wake up and find your arm tingling because the circulation stopped as you were lying on it. Some schools of psychiatry use dreams as a portal into the mind of a patient and try to interpret dreams as a way to help patients overcome their problems. Mystics view dreams as visions into the future or revelations from God. The book of Genesis provides at least four instances of dreams being used by God or his messengers as a means for communicating with people.
The capability for solving complex logical problems may be what differentiates humans, more than anything else, from other living beings. Logic is what makes us understand that things are not what they seem. Our ability to visualize hypothetical situations makes it possible to develop solutions to problems. Once we have visualized a solution, our analytical skills can lead us toward practical solutions. We may not be able to see in the ultraviolet range, but we may design instruments to do so. We may not be able to see atoms, but we can design experiments that enable us to know their properties. Each stage of scientific advancement has usually been made by trying to reach a logical conclusion consistent with our observations. We no longer believe in demons as the cause of disease. We now believe in viruses, bacteria, genetic defects, and environmental pollution as the real causes of disease. Our irrational and unfounded "superstitions" have given way to "knowledge".
Subliminal perception and communication is one of the most interesting phenomena for anyone wanting to increase their psychic potential. The word "subliminal" means beyond the range of conscious perception. In other words, if a note is played beyond your range of hearing, or a visual image is flashed too fast, you will not be able to perceive it. However, experiments have shown that such subliminal messages do influence the decisions that we make. Subliminal messages may also be encoded, not by having stimuli beyond the limits of our perception, but by imbedding them in an unexpected context. Advertisers have used slim women and tough cowboys for promoting tobacco products. "You too can be like this" or "This is sexy" is the message. Subliminal messages do work. Nobody is immune to them. The transition from subliminal to conscious may never happen, but sometimes we get premonitions. We get the feeling that something is going to happen, but we do not know and cannot explain why we think so. This may be the assimilation of various subliminal perceptions that are trying to reach the conscious level.
There was once a horse named "Hans" that was reputed to be able to solve arithmetic problems. When asked to multiply two times two, the horse would tap its hoof four times. The horse had a successful mathematical career until scientists started to study it. When the horse was separated from its trainer it lost its ability to solve problems. After some experiments, it became apparent that the horse observed the expression of the trainer and stopped tapping its hoof when the trainer looked satisfied and became relaxed. Some dogs have been found to sense on-coming epileptic seizures in people, and can be trained to get help.
If animals can do it, people can do it too within the limits of their perception. The best palm readers can hold your hand and look at your face as they speak and thus feel your tensions and your emotions. They watch your pupils as they hold your hand and say "Let me see what you came to see me about ... love ... or work". Your reaction will give you away. The expression in your eyes, the dilation of your pupils, the tension of your hand, or the way you breathe can give a good observer clues about your interests. Besides, the palm reader is choosing two topics that are important to everybody. There is no way to go wrong! The polygraph, or lie-detector, automates the perception of these small clues to provide a more scientific basis for determining what a person is thinking about.
Oral and written communication have a huge effect on the mind. Earlier chapters discussed language as inputs and outputs from the body. The power of words cannot be underestimated. Words have the power to move nations into revolution. Words can be used to heal. Words can be used to hypnotize. Words can be used to pass messages to future generations. Voices from the past affect our daily lives today. More than 2300 years ago, Euclid developed exercises in geometry that are still used today, and Aristotle wrote about the five senses of the human body. Although we focus on "words" as a means of communication, we have to recognize that there are different kinds of languages. We could say that smells comprise a language. Bad smells mean "don't eat me", good smells mean "good to eat". There are specialized languages for mathematics. The inputs and outputs of an electronic calculator comprise a mathematical language. Although the mind is capable of working with many different language representations, visual and oral forms are the most common.