2. Physiological psychology
5. Gestalt psychology
7. Tests and Measurements
8. Development psychology
9. Social psychology
10. Psychiatry and mental health
11. Forensic psychology and criminology
12. Psychology, religion and phenomenology
14. Industrial Psychology
Psychology, scientific study of behavior and experience—that is, the study of how human beings and animals sense, think, learn, and know. Modern psychology is devoted to collecting facts about behavior and experience and systematically organizing such facts into psychological theories. These theories aid in understanding and explaining people’s behavior and sometimes in predicting and influencing their future behavior.
Psychology, historically, has been divided into many subfields of study; these fields, however, are interrelated and frequently overlap. Physiological psychologists, for instance, study the functioning of the brain and the nervous system, and experimental psychologists devise tests and conduct research to discover how people learn and remember. Subfields of psychology may also be described in terms of areas of application. Social psychologists, for example, are interested in the ways in which people influence one another and the way they act in groups. Industrial psychologists study the behavior of people at work and the effects of the work environment. School psychologists help students make educational and career decisions. Clinical psychologists assist those who have problems in daily life or who are mentally ill.
History. The science of psychology developed from many diverse sources, but its origins as a science may be traced to ancient Greece.
Philosophical Beginnings. Plato and Aristotle, as well as other Greek philosophers, took up some of the basic questions of psychology that are still under study: Are people born with certain skills, abilities, and personality, or do all these develop as a result of experience? How do people come to know the world? Are certain ideas and feelings innate, or are they all learned?
Such questions were debated for many centuries, but the roots of modern psychological theory are found in the 17th century in the works of the French philosopher Ren Descartes and the British philosophers Thomas Hobbes and John Locke. Descartes argued that the bodies of people are like clockwork machines, but that their minds (or souls) are separate and unique. He maintained that minds have certain inborn, or innate, ideas and that these ideas are crucial in organizing people’s experiencing of the world. Hobbes and Locke, on the other hand, stressed the role of experience as the source of human knowledge. Locke believed that all information about the physical world comes through the senses and that all correct ideas can be traced to the sensory information on which they are based.
Most modern psychology developed along the lines of Locke’s view. Some European psychologists who studied perception, however, held onto Descartes’s idea that some mental organization is innate, and the concept still plays a role in theories of perception and cognition.
Against this philosophical background, the field that contributed most to the development of scientific psychology was physiology—the study of the functions of the various organ systems of the body. The German physiologist Johannes Miller tried to relate sensory experience both to events in the nervous system and to events in the organism’s physical environment. The first true experimental psychologists were the German physicist Gustav Theodor Fechner and the German physiologist Wilhelm Wundt. Fechner developed experimental methods for measuring sensations in terms of the physical magnitude of the stimuli producing them. Wundt, who in 1879 founded the first laboratory of experimental psychology in Leipzig, Germany, trained students from around the world in this new science.
Physicians who became concerned with mental illness also contributed to the development of modern psychological theories. Thus, the systematic classification of mental disorders developed by the German psychiatric pioneer Emil Kraepelin remains the basis for methods of classification that are now in use. Far better known, however, is the work of Sigmund Freud, who devised the system of investigation and treatment known as psychoanalysis. In his work, Freud called attention to instinctual drives and unconscious motivational processes that determine people’s behavior. This stress on the contents of thought, on the dynamics of motivation rather than the nature of cognition in itself, exerted a strong influence on the course of modern psychology.
Modern psychology still retains many aspects of the fields and kinds of speculation from which it grew. Some psychologists, for example, are primarily interested in physiological research, others are medically oriented, and a few try to develop a more encompassing, philosophical understanding of psychology as a whole. Although some practitioners still insist that psychology should be concerned only with behavior—and may even deny the meaningfulness of an inner, mental life—more and more psychologists would now agree that mental life or experience is a valid psychological concern.
The areas of modern psychology range from the biological sciences to the social sciences.
2. Physiological psychology
The study of underlying physiological bases of psychological functions is known as physiological psychology. The two major communication systems of the body—the nervous system and the circulatory system—are the focus of most research in this area.
The nervous system consists of the central nervous system (the brain and the spinal cord) and its outlying neural network, the peripheral nervous system; the latter communicates with the glands and muscles and includes the sensory receptors for seeing, hearing, smelling, tasting, touching, feeling pain, and sensing stimuli within the body. The circulatory system circulates the blood and also carries the important chemical agents known as hormones from the glands to all parts of the body. Both these communication systems are very important in overall human behavior.
The smallest unit of the nervous system is the single nerve cell, or neuron. When a neuron is properly stimulated, it transmits electrochemical signals from one place in the system to another. The nervous system has 12.5 billion neurons, of which about 10 billion are in the brain itself.
One part of the peripheral nervous system, the somatic system, transmits sensations into the central nervous system and carries commands from the central system to the muscles involved in movement. Another part of the peripheral nervous system, the autonomic system, consists of two divisions that have opposing functions. The sympathetic division arouses the body by speeding the heartbeat, dilating the pupils of the eye, and releasing adrenaline into the blood. The parasympathetic division operates to calm the body by reversing these processes.
A simple example of communication within the nervous system is the spinal arc, which is seen in the knee-jerk reflex. A tap on the patellar tendon, just below the kneecap, sends a signal to the spinal cord via sensory neurons. This signal activates motor neurons that trigger a contraction of the muscle attached to the tendon; the contraction, in turn, causes the leg to jerk. Thus, a stimulus can lead to a response without involving the brain, via a connection through the spinal cord.
Circulatory communication is ordinarily slower than nervous-system communication. The hormones secreted by the body’s endocrine glands circulate through the body, influencing both structural and behavioral changes . The sex hormones, for example, that are released during adolescence effect many changes in body growth and development as well as changes in behavior, such as the emergence of specific sexual activity and the increase of interest in the opposite sex. Other hormones may have more direct, short-term effects; for instance, adrenaline, which is secreted when a person faces an emergency, prepares the body for a quick response—whether fighting or flight.
Psychoanalysis, name applied to a specific method of investigating unconscious mental processes and to a form of psychotherapy. The term refers, as well, to the systematic structure of psychoanalytic theory, which is based on the relation of conscious and unconscious psychological processes.
Theory of Psychoanalysis
The technique of psychoanalysis and much of the psychoanalytic theory based on its application were developed by Sigmund Freud. His work concerning the structure and the functioning of the human mind had far-reaching significance, both practically and scientifically, and it continues to influence contemporary thought.
The first of Freud’s innovations was his recognition of unconscious psychiatric processes that follow laws different from those that govern conscious experience. Under the influence of the unconscious, thoughts and feelings that belong together may be shifted or displaced out of context; two disparate ideas or images may be condensed into one; thoughts may be dramatized in the form of images rather than expressed as abstract concepts; and certain objects may be represented symbolically by images of other objects, although the resemblance between the symbol and the original object may be vague or farfetched. The laws of logic, indispensable for conscious thinking, do not apply to these unconscious mental productions.
Recognition of these modes of operation in unconscious mental processes made possible the understanding of such previously incomprehensible psychological phenomena as dreaming. Through analysis of unconscious processes, Freud saw dreams as serving to protect sleep against disturbing impulses arising from within and related to early life experiences. Thus, unacceptable impulses and thoughts, called the latent dream content, are transformed into a conscious, although no longer immediately comprehensible, experience called the manifest dream. Knowledge of these unconscious mechanisms permits the analyst to reverse the so-called dream work, that is, the process by which the latent dream is transformed into the manifest dream, and through dream interpretation, to recognize its underlying meaning.
A basic assumption of Freudian theory is that the unconscious conflicts involve instinctual impulses, or drives, that originate in childhood. As these unconscious conflicts are recognized by the patient through analysis, his or her adult mind can find solutions that were unattainable to the immature mind of the child. This depiction of the role of instinctual drives in human life is a unique feature of Freudian theory.
According to Freud’s doctrine of infantile sexuality, adult sexuality is an end product of a complex process of development, beginning in childhood, involving a variety of body functions or areas (oral, anal, and genital zones), and corresponding to various stages in the relation of the child to adults, especially to parents. Of crucial importance is the so-called Oedipal period, occurring at about four to six years of age, because at this stage of development the child for the first time becomes capable of an emotional attachment to the parent of the opposite sex that is similar to the adult’s relationship to a mate; the child simultaneously reacts as a rival to the parent of the same sex. Physical immaturity dooms the child’s desires to frustration and his or her first step toward adulthood to failure. Intellectual immaturity further complicates the situation because it makes children afraid of their own fantasies. The extent to which the child overcomes these emotional upheavals and to which these attachments, fears, and fantasies continue to live on in the unconscious greatly influences later life, especially love relationships.
The conflicts occurring in the earlier developmental stages are no less significant as a formative influence, because these problems represent the earliest prototypes of such basic human situations as dependency on others and relationship to authority. Also basic in molding the personality of the individual is the behavior of the parents toward the child during these stages of development. The fact that the child reacts, not only to objective reality, but also to fantasy distortions of reality, however, greatly complicates even the best-intentioned educational efforts.
Id, Ego, and Superego
The effort to clarify the bewildering number of interrelated observations uncovered by psychoanalytic exploration led to the development of a model of the structure of the psychic system. Three functional systems are distinguished that are conveniently designated as the id, ego, and superego.
The first system refers to the sexual and aggressive tendencies that arise from the body, as distinguished from the mind. Freud called these tendencies Triebe, which literally means “drives,” but which is often inaccurately translated as “instincts” to indicate their innate character. These inherent drives claim immediate satisfaction, which is experienced as pleasurable; the id thus is dominated by the pleasure principle. In his later writings, Freud tended more toward psychological rather than biological conceptualization of the drives.
How the conditions for satisfaction are to be brought about is the task of the second system, the ego, which is the domain of such functions as perception, thinking, and motor control that can accurately assess environmental conditions. In order to fulfill its function of adaptation, or reality testing, the ego must be capable of enforcing the postponement of satisfaction of the instinctual impulses originating in the id. To defend itself against unacceptable impulses, the ego develops specific psychic means, known as defense mechanisms. These include repression, the exclusion of impulses from conscious awareness; projection, the process of ascribing to others one’s own unacknowledged desires; and reaction formation, the establishment of a pattern of behavior directly opposed to a strong unconscious need. Such defense mechanisms are put into operation whenever anxiety signals a danger that the original unacceptable impulses may reemerge.
An id impulse becomes unacceptable, not only as a result of a temporary need for postponing its satisfaction until suitable reality conditions can be found, but more often because of a prohibition imposed on the individual by others, originally the parents. The totality of these demands and prohibitions constitutes the major content of the third system, the superego, the function of which is to control the ego in accordance with the internalized standards of parental figures. If the demands of the superego are not fulfilled, the person may feel shame or guilt. Because the superego, in Freudian theory, originates in the struggle to overcome the Oedipal conflict, it has a power akin to an instinctual drive, is in part unconscious, and can give rise to feelings of guilt not justified by any conscious transgression. The ego, having to mediate among the demands of the id, the superego, and the outside world, may not be strong enough to reconcile these conflicting forces. The more the ego is impeded in its development because of being enmeshed in its earlier conflicts, called fixations or complexes, or the more it reverts to earlier satisfactions and archaic modes of functioning, known as regression, the greater is the likelihood of succumbing to these pressures. Unable to function normally, it can maintain its limited control and integrity only at the price of symptom formation, in which the tensions are expressed in neurotic symptoms.
A cornerstone of modern psychoanalytic theory and practice is the concept of anxiety, which institutes appropriate mechanisms of defense against certain danger situations. These danger situations, as described by Freud, are the fear of abandonment by or the loss of the loved one (the object), the risk of losing the object’s love, the danger of retaliation and punishment, and, finally, the hazard of reproach by the superego. Thus, symptom formation, character and impulse disorders, and perversions, as well as sublimations, represent compromise formations—different forms of an adaptive integration that the ego tries to achieve through more or less successfully reconciling the different conflicting forces in the mind.
Various psychoanalytic schools have adopted other names for their doctrines to indicate deviations from Freudian theory.
Carl Gustav Jung, one of the earliest pupils of Freud, eventually created a school that he preferred to call analytical psychology. Like Freud, Jung used the concept of the libido; however, to him it meant not only sexual drives, but a composite of all creative instincts and impulses and the entire motivating force of human conduct. According to his theories, the unconscious is composed of two parts; the personal unconscious, which contains the results of the individual’s entire experience, and the collective unconscious, the reservoir of the experience of the human race. In the collective unconscious exist a number of primordial images, or archetypes, common to all individuals of a given country or historical era. Archetypes take the form of bits of intuitive knowledge or apprehension and normally exist only in the collective unconscious of the individual. When the conscious mind contains no images, however, as in sleep, or when the consciousness is caught off guard, the archetypes commence to function. Archetypes are primitive modes of thought and tend to personify natural processes in terms of such mythological concepts as good and evil spirits, fairies, and dragons. The mother and the father also serve as prominent archetypes.