The capacity to learn, commonly known as aptitude, and the demonstration of skills and knowledge already learned, called achievement, are among the factors used to evaluate intelligence. When evaluating or comparing subjects, two kinds of abilities are considered: verbal ability, including reading comprehension, ability to converse, vocabulary, and the use of language; and problem-solving ability,…
Abortion is the final consequence of a woman's decision to terminate her pregnancy. In the U.S., more than 50% of the pregnancies are unintended, and 50% of these end in abortion. More than half (53%) of the unplanned pregnancies happen among the 10% of women who practice no contraception. Most women getting abortions are young: 55% are under 25, including 21% teenagers. Between five a…
The method of testing for the absolute threshold is similar for different sensory systems. Thus, the tester can briefly present a light or a sound (or any other kind of stimulus) at different, low intensities until the observer is unable to detect the presence of the stimulus. In such a task, the person may undergo thousands of trials before the researcher can determine the threshold. While the ab…
Acculturation is the process of learning about and adapting to a new culture. A new culture may require adjustments in all or some of the aspects of daily living, including language, work, shopping, housing, children's schooling, health care, recreation, and social life. Relocation to a society that is similar to one's own requires less acculturation than moving to a society where cu…
An action potential is transmitted along a nerve fiber as a wave of changing electrical charge. This wave travels at a speed that ranges from about five feet (1.5 m) per second to about 350 feet (107 m) per second, depending on various properties of the nerve fiber involved and other factors. An action potential occurs in about one millisecond. During an action potential, there is a change in volt…
Adaptation describes the process of change in organisms or species to accommodate to a particular environment, enabling their survival. Adaptation is crucial to the process of natural selection. Ethologists, scientists who study the behavior of animals in their natural habitats from an evolutionary perspective, have documented two main types of adaptive behavior. Some behaviors, known as "c…
Addiction has come to refer to a wide and complex range of behaviors. In addition to familiar addictions, such as alcohol dependence, drug dependence, and smoking, addictive behavior has also been associated with food, exercise, work, and even relationships with others (codependency). Some experts describe the spectrum of behaviors designated as addictive in terms of five interrelated concepts: pa…
A person's affect is the expression of emotion or feelings displayed to others through facial expressions, hand gestures, voice tone, and other emotional signs such as laughter or tears. Individual affect fluctuates according to emotional state. What is considered a normal range of affect, called the broad effect, varies from culture to culture, and even within a culture. Certain individual…
The need to form attachments with others is termed affiliation. Attachment is one of 20 psychological needs measured by the Thematic Apperception Test, a projective personality test developed at Harvard University in 1935 by Henry Murray. Subjects look at a series of up to 20 pictures of people in a variety of recognizable settings and construct a story about what is happening in each one. The nee…
Aggressive behavior is often used to claim status, precedent, or access to an object or territory. While aggression is primarily thought of as physical, verbal attacks aimed at causing psychological harm also constitute aggression. In addition, fantasies involving hurting others can also be considered aggressive. The key component in aggression is that it is deliberate—accidental injuries a…
Psychological studies of aging populations began in earnest in the late nineteenth century when psychologists found that mental abilities deteriorated with age. These abilities included memory and the types of mental performance measured in IQ tests. In some individuals, verbal abilities were shown to deteriorate with advanced age, although at a slower rate than other skills; with others, verbal a…
The American Psychiatric Association ranks alcohol dependence and abuse into three categories (what society normally thinks of as "alcoholics"): 1) individuals who consume alcohol regularly, usually daily, in large amounts 2) those who consume alcohol regularly and heavily, but, unlike the first group, have the control to confine their excessive drinking to times when there are fewer…
Compound of the Branch Davidians in Waco, Texas. Feelings of alienation sometimes lead people to form small, close-knit groups such as cults. (AP/Wide World Photos. Reproduced with permission.) Alienation is a powerful feeling of isolation and loneliness, and stems from a variety of causes. Alienation may occur in response to certain events or situations in society or in one's person…
In 1990, approximately 40 million Americans could be classified as having one or more physical or mental disabilities. The Americans with Disabilities Act (ADA) was enacted to legally address the widespread and serious social problem of discrimination against these individuals in employment, housing, public accommodations, education, transportation, communication, public service, and other areas. …
Anger is usually caused by the frustration of attempts to attain a goal, or by hostile or disturbing actions such as insults, injuries, or threats that do not come from a feared source. The sources of anger are different for people at different periods in their lives. The most common cause of anger in infants, for example, is restraint of activity. Children commonly become angry due to restrictive…
The two most common types of antidepressants are tricyclic antidepressants (TCAs) and selective serotonin re-uptake inhibitors (SSRIs). Examples of TCAs include nortriptyline (also known by the brand name Pamelor), imipramine (Tofranil), and desipramine (Norpramin). Examples of SSRIs include fluoxetine (Prozac), sertraline (Zoloft), and paroxetine (Paxil). Clinical studies have shown that some peo…
Archetypes are primordial images and symbols found in the collective unconscious, which—in contrast to the personal unconscious—gathers together and passes on the experiences of previous generations, preserving traces of humanity's evolutionary development over time. Carl Jung began to evolve his theory of archetypes around 1910 while working with patients at the Burghö…
The study of artificial intelligence, referred to as AI, has accelerated in recent years as advancements in computer technology have made it possible to create more and more sophisticated machines and software programs. The field of AI is dominated by computer scientists, but it has important ramifications for psychologists as well because in creating machines that replicate human thought, much is…
Advanced primarily by a succession of 18th- and 19th-century British philosophers, associationism anticipated developments in the modern field of psychology in a variety of ways. In its original empiricist context, it was a reaction against the Platonic philosophy of innate ideas that determined, rather than derived from, experience. Instead, the associationists proposed that ideas originated in e…
Many developmental psychologists view attachment—the special relationship between infant and care-giver—as an important building block for later relationships and adult personality. Since attachment plays a central role in theories of social and emotional development, the scientific study of attachment has remained in the forefront of developmental psychology for the past several dec…
Attention describes the focusing of perceptive awareness on a particular stimulus or set of stimuli that results in the relative exclusion of other stimuli and is often accompanied by an increase in the readiness to receive and to respond to the stimulus or set of stimuli involved. A state of attention may be produced initially in many ways, including as a conscious, intentional decision, as a nor…
People hold complex relationships between attitudes and behavior that are further complicated by the social factors influencing both. Behaviors usually, but not always, reflect established beliefs and attitudes. For example, a man who believes strongly in abstinence before marriage may choose to remain a virgin until his wedding night. Under other circumstances, that same man may engage in premari…
Attitudes have three main components: cognitive, affective, and behavioral. The cognitive component concerns one's beliefs; the affective component involves feelings and evaluations; and the behavioral component consists of ways of acting toward the attitude object. The cognitive aspects of attitude are generally measured by surveys, interviews, and other reporting methods, while the affect…
Both personal characteristics and environment play a role in interpersonal attraction. A major determinant of attraction is propinquity, or physical proximity. People who come into contact regularly and have no prior negative feelings about each other generally become attracted to each other as their degree of mutual familiarity and comfort level increases. The situation in which people first meet…
Adolf Hitler and his troops. Authoritarian personality types project their own weaknesses onto groups they denigrate as inferior. (Reproduced with permission.) Theodor Adorno (1903-1969) led a team of researchers at the University of California, Berkeley, to determine whether there was a correlation between anti-Semitism and certain personality traits. While the original goal had been the i…
Autoeroticism is the scientific term used to describe masturbation, the stimulation of the genital organs to achieve orgasm. Although masturbation was widely condemned in most premodern societies, and has been the subject of remarkable and persistent superstitions and extreme taboos, there is evidence that contemporary attitudes toward masturbation are becoming increasingly tolerant of this behavi…
The nervous system consists of two main structures, the central nervous system (the brain and the spinal cord) and the peripheral nervous system (the sense organs and the nerves linking the sense organs, muscles, and glands to the central nervous system). The structures of the peripheral nervous system are further subdivided into the autonomic nervous system (automatic bodily processes) and the so…
The cause of avoidant personality disorder is not clearly defined, and may be influenced by a combination of social, genetic, and biological factors. Avoidant personality traits typically appear in childhood, with the appearance of excessive shyness and fear of new people and situations. However, these characteristics are also developmentally appropriate emotions for children, and do not necessari…
Behaviorism is a psychological theory of human development that posits that humans can be trained, or conditioned, to respond in specific ways to specific stimuli and that given the correct stimuli, personalities and behaviors of individuals, and even entire civilizations, can be codified and controlled. Edward Thorndike (1874-1949) initially proposed that humans and animals acquire behaviors thro…
The language rights of ethnic minorities in the United States have been a source of public controversy for close to two decades. The 1970s saw record levels of immigration, bringing an estimated 4 million legal and 8 million illegal immigrants into the country. To accommodate this dramatic surge in the nation's population of foreign language speakers, language assistance has been mandated o…
Binocular depth cues are based on the simple fact that a person's eyes are located in different places. One cue, binocular disparity, refers to the fact that different optical images are produced on the retinas of both eyes when viewing an object. By processing information about the degree of disparity between the images it receives, the brain produces the impression of a single object that…
Biofeedback originated with the field of psychophysiology, which measures physiological responses as a way of studying human behavior. Types of behavior that may be studied in this way range from basic emotional responses to higher cognitive functions. Today, biofeedback is also associated with behavioral medicine, which combines behavioral and biomedical science in both clinical and research sett…
There is no single accepted definition of bisexuality. Some define it narrowly as sexual involvement with members of both sexes concurrently (within a twelve-month period or less). Others define bisexuality more broadly as any sexual attraction to or involvement with members of both sexes at any time in one's life. However, few people qualify as bisexual in its narrow definition. A comprehe…
Humans have the unique ability to form abstract conceptions about themselves and to gaze at themselves as both the seer and the object seen. Conflict occurs when the seer places unrealistic demands on him or herself and the body. Body image considers physical appearance and may include body functions or other features. Body image is linked to internal sensations, emotional experiences, fantasies, …
Borderline individuals have a history of unstable interpersonal relationships. They have difficulty seeing the "shades of gray" in the world, and view significant people in their lives as either completely flawless or extremely unfair and uncaring (a phenomena known as splitting). These alternating feelings of idealization and devaluation are the hallmark feature of borderline person…
Everyone, at one time or another, feels bored. Children, however, may report boredom more frequently because they have not yet learned to alleviate it for themselves. Infants and toddlers rarely experience boredom. Infants spend large blocks of time asleep and much of their waking time feeding. Toddlers have a nearly unlimited curiosity to explore a world that is still new to them. Preschool and s…
The brain, with the spinal cord and network of nerves, controls information flow throughout the body, voluntary actions, such as walking, reading, and talking, and involuntary reactions, such as breathing and heartbeat. The human brain is a soft, shiny, grayish white, mushroom-shaped structure. Encased within the skull, the brain of an average adult weight about 3 lb (1.4 kg). At birth, the averag…
Brainwashing has been used predominantly in reference to severe programs of political indoctrination, although it is used occasionally in connection with certain religious, especially cultic, practices. Brainwashing works primarily by making the victim's existing beliefs and attitudes nonfunctional and replacing them with new ones that will be useful in the environment created by the captor…
The term bystander effect, or bystander apathy, was first employed by psychologists in the early 1960s. The 1964 murder of New Yorker Kitty Genovese provides an illustration of this phenomenon. Genovese, who was being savagely attacked outside her apartment building, screamed for help for over 30 minutes. Although 40 neighbors heard Genovese's desperate cries, no one came to her aid or even…
A case study (or case history) consists of an intensive, detailed description and analysis of a particular individual, group, or event. Information may be obtained by means of careful observation, interviews, psychological tests, or archival records. Case study research is useful when the researcher is starting to investigate a new area in which there is little information available. Case studies …
The term catharsis originated from the Greek word katharsis, meaning to purge, or purgation. In psychology, the term was first employed by Sigmund Freud's colleague Josef Breuer (1842-1925), who developed a "cathartic" treatment for persons suffering from hysterical symptoms through the use of hypnosis. While under hypnosis, Breuer's patients were able to recall traumat…
The English word for cathexis—which replaces the German besetzung—is derived from the Greek word for "I occupy." Through the process of cathexis, which Sigmund Freud saw as analogous to the channeling of an electrical charge, the psychic energy of the id is bound to a selection of objects. An infant's earliest cathected objects are his mother's breast, his…
The central nervous system contains billions of nerve cells, called neurons, and a greater number of support cells, or glia. Until recently, scientists thought that the only function of glial cells—whose name means "glue"—was to hold the neurons together, but current research suggests a more active role in facilitating communication. The neurons, which consist of three …
Character is most often used in reference to a set of basic innate, developed, and acquired motivations that shape an individual's behavior. These qualities of an individual's motivation are shaped during all stages of childhood. By late adolescence, around age 17, the traits that make up individual's character are normally integrated into a unique and distinctive whole. The t…
Classical conditioning is an important concept in the school of psychology known as behaviorism, and it forms the basis for some of the techniques used in behavior therapy. Classical conditioning was pioneered by the Russian physiologist Ivan Pavlov (1849-1936) in the 1890s in the course of experiments on the digestive systems of dogs (work which won him the Nobel Prize in 1904). Noticing that the…
Developed in the 1930s by the American psychologist Carl Rogers, client-centered therapy—also known as non-directive or Rogerian therapy—departed from the typically formal, detached role of the therapist common to psychoanalysis and other forms of treatment. Rogers believed that therapy should take place in the supportive environment created by a close personal relationship between c…
Clinical psychologists apply research findings in the fields of mental and physical health to explain dysfunctional behavior in terms of normal processes. The problems they address are diverse and include mental illness, mental retardation, marital and family issues, criminal behavior, and chemical dependency. The clinical psychologist may also address less serious problems of adjustment similar t…
The term clique has two levels of significance. In its neutral usage by social researchers, it denotes a group of people who interact with each other more intensively than with other peers in the same setting. In its more popular form it has negative connotations. It is used to describe an adolescent social group that excludes others on the basis of superficial differences, exercising greater than…
The concept of codependence was first developed in relation to alcohol and other substance abuse addictions. The alcoholic or drug abuser was the dependent, and the person involved with the dependent person in any intimate way (spouse, lover, child, sibling, etc.) was the codependent. The definition of the term has been expanded to include anyone showing an extreme degree of certain personality tr…
Cognition depends on the ability to imagine or represent objects and events that are not physically present at a given moment. Cognitive functions include attention, perception, thinking, judging, decision making, problem solving, memory, and linguistic ability. One of the most basic cognitive functions is the ability to conceptualize, or group individual items together as instances of a single co…
Historically, the cognitive development of children has been studied in a variety of ways. The oldest is through intelligence tests, such as the widely used Stanford Binet Intelligence Quotient, or IQ, test first adopted for use in the United States by psychologist Lewis Terman (1877-1956) in 1916 from a French model pioneered in 1905. IQ scoring is based on the concept of "mental age,�…
First proposed by Leon Festinger in 1957, the theory of cognitive dissonance is based on the principle that people prefer their cognitions, or beliefs, to be consistent with each other and with their own behavior. Inconsistency, or dissonance, among their own ideas makes people uneasy enough to alter these ideas so that they will agree with each other. For example, smokers forced to deal with the …
The cognitive psychologist studies human perceptions and the ways in which cognitive processes operate to produce responses. Cognitive processes (which may involve language, symbols, or imagery) include perceiving, recognizing, remembering, imagining, conceptualizing, judging, reasoning, and processing information for planning, problem-solving, and other applications. Some cognitive psychologists …
Psychologist Aaron Beck developed the cognitive therapy concept in the 1960s. The treatment is based on the principle that maladaptive behavior (ineffective, self-defeating behavior) is triggered by inappropriate or irrational thinking patterns, called automatic thoughts. Instead of reacting to the reality of a situation, an individual automatically reacts to his or her own distorted viewpoint of …
Color vision is a function of the brain's ability to interpret the complex way in which light is reflected off every object in nature. What the human eye sees as color is not a quality of an object itself, nor a quality of the light reflected off the object; it is actually an effect of the stimulation of different parts of the brain's visual system by the varying wavelengths of light…
A coma may be induced by a severe neurological injury—either temporary or permanent—or by other physical trauma. A comatose individual cannot be aroused by even the most intense stimuli, although he or she may show some automatic movements in response to pain. Comas often occur just before death in the course of many diseases. The affected brain cells may be either near the surface (…
Combat neurosis describes any personality disturbance that represents a response to the stress of war. It is closely related to post-traumatic stress disorder, and is often characterized under that term. Symptoms of the disturbance may appear during the battle itself, or may appear days, weeks, months, or even years later. An estimated ten percent of all personnel who fought in World War II experi…
Studies of animal behavior have taken two main directions in the twentieth century. The type of research most often practiced in the United States has been animal research, involving the study of animals in laboratories and emphasizing the effects of environment on behavior. European research, by comparison, has been more closely associated with the area of inquiry known as ethology, which concent…
Defendants in a criminal trial must have the ability (i.e., the competence) to understand the charges, to consult with an attorney, and to have a rational grasp of the courtroom proceedings. This requirement is a longstanding and fundamental principle of criminal law. Its purpose is to ensure that defendants can participate meaningfully in their own defense. The requirement refers to the defendant…
Psychologists have long been in disagreement as to whether competition is a learned or a genetic component of human behavior. Perhaps what first comes to mind when thinking of competition is athletics. It would be a mistake, however, not to recognize the effect competition has in the areas of academics, work, and many other areas of contemporary life. This is especially true in the United States, …
Along with anxiety and depression, conduct disorder is one of the most frequently diagnosed childhood psychological disorders. Depending on the population, rates of the disorder range from 6-16% in males and 2-9% in females and are expected to increase as antisocial behavior increases. Symptoms of conduct disorder include aggression, destruction of property, deceitfulness or theft, Depending on th…
"Conflict" from the Latin root "to strike together" can be defined as any situation where incompatible activities, feelings, or intentions occur together. Conflict may take place within one person, between two or more people who know each other, or between large groups of people who do not know each other. It may involve actual confrontation between persons, or merely s…
Conformity describes the adaptation of behavior that occurs in response to unspoken group pressure. It differs from compliance, which is adaptation of behavior resulting from overt pressure. Individuals conform to or comply with group behavior in an attempt to "fit in" or to follow the norms of the social group. In most cases, conforming to social norms is so natural that people aren…
Wilhelm Wundt's investigations of consciousness, begun in 1879, were central to the development of psychology as a field of study. Wundt's approach, called structuralism, sought to determine the structure of consciousness by recording the verbal descriptions provided by laboratory subjects to various stimuli, a method that became known as introspection. The next major approach to the…
Consumer psychology seeks to explain human, or consumer behavior, in two basic ways: what the consumer wants and what the consumer needs. The logical explanation for fulfilling the needs is a simple one. If a person lives in New York, that person needs a winter coat to survive the cold outside. But why the person buys a particular style or color hinges on the more complex issues of why a particula…
Scientists often study how a particular condition or factor influences an outcome. In such an experiment, in which there are two groups of subjects, the group that is exposed to the condition or factor is called the experimental group. The other group, which provides a basis for comparison, is called the control group. For example, in a hypothetical study of the influence of the presence of loud m…
The term convergent thinking was coined J. P. Guilford, a psychologist well-known for his research on creativity. Guilford posited that a prime component of creativity is divergent thinking, the capacity to arrive at unique and original solutions and the tendency to consider problems in terms of multiple solutions rather than just one. Convergent thinking, which narrows all options to one solution…
Psychologists are often interested in deciding whether two behaviors tend to occur together. One means of making this assessment involves using correlations. Sometimes two measurements are associated so that when the value of one increases, so does the other— a positive correlation. On the other hand, one value may increase systematically as the other decreases—a negative correlation…