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,…
Abnormal behavior is defined as behavior that is considered to be maladaptive or deviant by the social culture in which it occurs. Though disagreement exists regarding which particular behaviors can be classified as abnormal, psychologists have defined several criteria for purposes of classification. One is that the behavior occurs infrequently and thus deviates from statistical norms. Another is …
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…
Spelling tests, timed arithmetic tests, and map quizzes are all examples of achievement tests. Each measures how well students can demonstrate their knowledge of a particular academic subject or skill. Achievement tests on a small scale like these are administered frequently in schools. Less frequently, students are given more inclusive achievement tests that cover a broader spectrum of informatio…
Nathan Ward Ackerman was born in Bessarabia, Russia on November 22, 1908. His parents were pharmacist David Ackerman and Bertha (Greenberg) Ackerman. They came to the United States in 1912, and were naturalized in 1920. He was married to Gwendolyn Hill on October 10, 1937. They had two daughters, Jeanne and Deborah. Ackerman attended a public school in New York City. In 1929 he was awarded a B.A. …
Since Acquired Immune Deficiency Syndrome (AIDS) manifests itself in a number of different diseases and conditions, it has been difficult to arrive at a formal definition. In an attempt to standardize the definition of AIDS, the Centers for Disease Control in 1992 included among its diagnostic criteria a count of 200 or fewer CD4T lymphocyte cells per cubic ml of blood (a sign of severe immune sys…
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…
Adjustment disorders are maladpative, or unhealthy, responses to stressful or psychologically distressing life events, such as the end of a romantic relationship or being terminated from a job. The American Psychiatric Association has identified and categorized several varieties of adjustment disorders, depending on accompanying symptoms and their duration. These subtypes include adjustment disord…
Alfred Adler was born in a suburb of Vienna, Austria, in 1870. After graduating from the University of Vienna medical school in 1895, he at first practiced ophthalmology but later switched to psychiatry. In 1902, Adler joined the discussion group that later became the Vienna Psychoanalytic Society. Sigmund Freud was also a member. Adler eventually became president and editor of its journal. After …
In the study of child development, adolescence refers to the second decade of the life span, roughly from ages 10 to 20. The word adolescence is Latin in origin, derived from the verb adolescere, which means "to grow into adulthood." In all societies, adolescence is a time of growing up, of moving from the immaturity of childhood into the maturity of adulthood. Population projections…
An adult assumes the role of parent for a child other than his or her own biological offspring in the process of adoption. Informal adoptions occur when a relative or stepparent assumes permanent parental responsibilities without court involvement. However, legally recognized adoptions require a court or other government agency to award permanent custody of a child (or, occasionally, an older indi…
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…
Mary D. Satler Ainsworth graduated from the University of Toronto in 1935 and earned her Ph.D. in psychology from that same institution in 1939. She is best known for her landmark work in assessing the security of infant attachment and linking attachment security to aspects of maternal care giving. Ainsworth began her career teaching at the University of Toronto before joining the Canadian Women&#…
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…
Gordon Willard Allport was one of the great personality theorists of the twentieth century. His work was a synthesis of individual personality traits and the traditional psychology of William James, which emphasized psychological traits that are common among humans. He also examined complex social interactions. As a humanistic psychologist, he opposed both behavioral and psychoanalytical theories …
Alzheimer's disease is the most common degenerative brain disorder, although onset of the disease is rare before the age of 60. After that age, the incidence of Alzheimer's disease increases steadily, and more than one-quarter of all individuals above the age of 85 have this disease. In addition, Alzheimer's disease is the cause of about three-quarters of all cases of dementia…
The Academy was established in 1953 as the American Academy of Child Psychiatry with fewer than 100 members. Today the AACAP is a dynamic, growing organization whose mission is to direct and respond quickly to new developments in the health care environment, particularly as they affect the needs of children, adolescents, and their families. The Academy sponsors over 45 committees which work to inc…
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. …
People make sense out of visual scenes by relying on various cues. The Ames Room is a specially constructed space that demonstrates the power of these cues. Normally, people use monocular depth cues such as relative size and height in the visual plane as indicators of depth. If two people of similar size stand a distance part, the one closer to the viewer appears larger. Similarly, the person fart…
There are numerous causes of amnesia, including stroke, injury to the brain, surgery, alcoholism, encephalitis, and electroconvulsive therapy. Contrary to the popular notion of amnesia—in which a person suffers a severe blow to the head, for example, and cannot recall his or her past life and experiences—the principal symptom of amnesia is the inability to retain new information, beg…
The oldest medical specialty society in the United States, the American Psychiatric Association was founded in October 1844, when thirteen physicians who specialized in the treatment of mental and emotional disorders met in Philadelphia and founded the Association of Medical Superintendents of American Institutions for the Insane. (It is interesting to note that this forerunner of the American Psy…
The program of the APA is organized in four directorates, namely Science, Practice, Public Interest, and Education, all of which contribute to the goal of seeking ways to increase human wellness through an understanding of behavior. The Science Directorate promotes the exchange of ideas and research findings through conventions, conferences, publications, and traveling museum exhibits. It also hel…