Withdrawal behavior is characterized by the tendency to avoid the unfamiliar, either people, places, or situations. Though withdrawal, or avoidance, can be the result of a temperamental tendency toward inhibition to unfamiliar events, anxiety over the anticipation of a critical evaluation, or a conditioned avoidant response, often called a phobia, can produce withdrawal. These are three different …
Mental images are created by the brain from memories, imagination, or a combination of both. In the 1990s, scientists were gaining knowledge of how the brain forms these visual pictures without input from the eyes. According to researchers at Harvard University, the brain may generate these mental pictures in the area of the brain responsible for vision. Stephen Kosslyn, a psychologist, used posit…
In Erik Erikson's influential scheme of human development, middle age is the period in which an individual is presented with the developmental task of choosing between ego stagnation (self-interest) and generativity, the capacity to care for others and make a positive contribution to society by being productive in work, parenting, or other activities. Carl Jung characterized the middle year…
Military psychology, when defined broadly, can include a vast array of activities in psychological research, assessment, and treatment. Military psychologists may be either soldiers or civilians. The field can encompass every aspect of the human mind that interests the military., but researchers focus on the psychology of military organization, military life, and the psychology of combat. Military…
The basic coding procedure common to most mnemonic strategies is to mentally associate, in some manner, items of new or unfamiliar information with various interconnected parts of a familiar, known whole. Mnemonic devices range from the very simple to the remarkably complex. An example of a very simple mnemonic device is the use of the acronymic word HOMES to remember the names of the Great Lakes …
In statistics, the mode is a descriptive number that indicates the most frequently occurring score or scores in a group of numbers. Along with the mean and the median, the mode constitutes the grouping of descriptive statistics known as measures of central tendency. Although the mode is the easiest of the measures of central tendency to determine, it is the least used because it gives only a crude…
A mood, while relatively pervasive, is typically neither highly intense nor sustained over an extended period of time. Examples of mood include happiness, sadness, contemplativeness, and irritability. The definitions of phrases to describe moods—such as good mood and bad mood—are imprecise. In addition, the range of what is regarded as a normal or appropriate mood varies considerably…
The study of motivation is concerned with the influences that govern the initiation, direction, intensity, and persistence of behavior. Three categories of motives have been recognized by many researchers: primary or biological (hunger and the regulation of food intake); stimulus-seeking (internal needs for cognitive, physical, and emotional stimulation, or intrinsic and extrinsic rewards); and le…
Narcissism is the personality trait that features an exaggerated sense of the person's own importance and abilities. People with this trait believe themselves to be uniquely gifted and commonly engage in fantasies of fabulous success, power, or fame. Arrogant and egotistical, narcissistics are often snobs, defining themselves by their ability to associate with (or purchase the services of) …
A narcotic is a depressant that produces a stuporous state in the person who takes it. Narcotics, while often inducing a state of euphoria or feeling of extreme well being, are powerfully addictive. The body quickly builds a tolerance to narcotics, so that greater doses are required to achieve the same effect. Because of their addictive qualities, most countries have strict laws regarding the prod…
The nature-nurture controversy is an age-old dispute among behavioral psychologists, philosophers, theologians, and theorists of consciousness as to the source of the creation ofhuman personality: Does it develop primarily from biology (nature), or from the environments in which we are raised (nurture)? People have been pondering the role of nature and environmentsince the time of Hippocrates (c. …
Tales of near-death experiences (NDEs) are not unusual. Out-of-body experiences, the sensation of moving through a tunnel toward a light, the review of the events of one's life, and pleasurable glimpses of other worlds are relatively consistent features of people's "near death" reports. In fact, research suggests that almost one fifth of Americans report having almost d…
Negativism is a behavior characterized by the tendency to resist direction from others, and the refusal to comply with requests. Negativism appears and wanes at various stages of a person's development. Active negativism, that is, behavior characterized by doing the opposite of what is being asked, is commonly encountered with young children. For example, a parent may ask a toddler to come …
The neocortex, the exterior covering of the cerebral hemispheres of the brain, is approximately 2 millimeters thick and consists of six thin layers of cells. The cortex is convoluted, furrowed, and, if stretched out, would measure 1.5 square feet. In terms of function, the cortex is divided into four lobes distinguished by the lateral and central fissures: the frontal lobe; parietal lobe (which co…
Nerves form the network of connections that receive signals, known as sensory input, from the environment and within the body and transmit the body's responses, or instructions for action, to the muscles, organs, and glands. The central nervous system, comprised of the brain and spinal cord, sends information throughout the body over the network of nerves known collectively as the periphera…
The nervous system is responsible for the perception of external and internal conditions and the body's response to them. It has two major divisions: the central and peripheral nervous systems. The central nervous system (CNS), consisting of the brain and the spinal cord, is that part of the nervous system that is encased in bone; the brain is located in the cranial cavity of the skull, and…
Neurons are the basic working unit of the nervous system, sending, receiving, and storing signals through a unique blend of electricity and chemistry. The human brain has more than 100 billion neurons. Neurons that receive information and transmit it to the spinal cord or brain are classified as afferent or sensory; those that carry information from the brain or spinal cord to the muscles or gland…
The word neurosis means "nerve disorder," and was first coined in the late eighteenth century by William Cullen, a Scottish physician. Cullen's concept of neurosis encompassed those nervous disorders and symptoms that do not have a clear organic cause. Sigmund Freud later used the term anxiety neurosis to describe mental illness or distress with extreme anxiety as a defining f…
Communication at the synapses between neurons relies on chemicals called neurotransmitters. Secreted from a part of one neuron (the axon) into the synaptic gap between two others, neurotransmitters diffuse across this space and combine with specific proteins on the surface of the receiving cell, triggering an electrochemical response in the target cell. Afterward, neurotransmitters are either dest…
Nightmares—frightening dreams—are experienced by most everyone at one time or another. Nightmares are thought to be caused by a central nervous system response, and are related to other parasomnias such as sleepwalking. In children, nightmares begin between the ages of 18 months and three years and increase in frequency and intensity around the ages of four and five years. Children t…
An example of the bell-shaped curve of a normal distribution. Psychological research involves measurement of behavior. This measurement results in numbers that differ from one another individually but that are predictable as a group. One of the common patterns of numbers involves most of the measurements being clustered together near the mean of the distribution, with fewer cases occurring …
In testing, norms are figures describing the frequency with which particular scores appear. They provide information about whether a score is above or below average and about what percentage of the persons tested received that score. Norms may apply to tests of mental ability or achievement, such as IQ tests or SATs. They are also used in personality assessment to measure variables such as anxiety…
For statistical purposes, normal means whatever is average for a given group of people ("the norm"). Therefore, the term normal does include those group members who deviate significantly from the measures of central tendency (the mean, the median, or the mode) of a given distribution. The term normal is fundamentally statistical and quantitative. In testing and measuring, for example…
Individuals who are 20 percent overweight are considered slightly obese. Those who are 40 percent above standard weight are moderately obese, while those 50 percent above it are morbidly obese. Persons who exceed desired weight levels by 100 pounds (45 kg) or more are hyperobese. Obesity is a serious health problem in the United States. Studies suggests that between 10 and 20 percent of Americans …
Obsessive-compulsive disorder (OCD) is classified as a mental illness, and is characterized by the recurrence of intrusive, anxiety-producing thoughts (obsessions). The person with obsessive-compulsive disorder repeatedly and consistently tries to suppress these thoughts through the performance of certain irrational, often ritualistic, behaviors (compulsions). Although there are marked similaritie…
The terms "overachiever" and "underachiever," most often applied to school and academia, both refer to gaps between academic performance and IQ test scores. Generally, these terms are not used by either educators or psychologists. However, clinical psychologist Marilyn Sorenson in her book, Breaking the Chain of Low Self-Esteem, maintains that people with low self-estee…
Pain is a complex phenomenon that scientists are still struggling to understand. Its purpose is to alert the body of damage or danger to its system, yet scientists do not fully understand the level and intensity of pain sometimes experienced by people. Long-lasting, severe pain does not serve the same purpose as acute pain, which triggers an immediate physical response. Pain that persists without …
To diagnose an individual with a paraphilia, the psychologist or other diagnostician must confirm recurrent, intense, sexually arousing feelings, fantasies, or behaviors over a period of at least six months. According to the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV), it is not uncommon for an individual to have more than one paraphilia. Bestiality is a term that describes sexu…
Pedophilia is a subcategory of a larger group of sexual disorders commonly classified as paraphilias. These are defined as recurrent, intense, aphrodisiac fantasies, sexual urges, or behaviors, over a period of at least six months, which involve non-human objects, the suffering or humiliation of oneself or one's partner, or children or other non-consenting partners. If these recurrent fanta…
Peer mediation is a form of conflict resolution based on integrative negotiation and mediation. Disputing parties converse with the goal of finding a mutually satisfying solution to their disagreement, and a neutral third party facilitates the resolution process. The salient feature of peer mediation as opposed to traditional discipline measures and other forms of conflict resolution is that, outs…
Psychologists have identified two general ways in which humans perceive their environment. One involves what is called "top-down" processing. In this mode, what is perceived depends on such factors as expectations and knowledge. That is, sensory events are interpreted based on a combination of what occurs in the external world and on existing thoughts, experience, and expectations. W…
Perfectionism is a psychological orientation which, depending on the severity, may have biological and/or environmental causes. To an educated observer, a perfectionist orientation is usually evident by the preschool years, though it may not cause problems until the college years. The perfectionist orientation has two components: impossibly high standards, and the behaviors intended to help achiev…
Personality is fundamental to the study of psychology. The major systems evolved by psychiatrists and psychologists since Sigmund Freud to explain human mental and behavioral processes can be considered theories of personality. These theories generally provide ways of describing personal characteristics and behavior, establish an overall framework for organizing a wide range of information, and ad…
The concept of personality refers to the profile of stable beliefs, moods, and behaviors that differentiate among children (and adults) who live in a particular society. The profiles that differentiate children across cultures of different historical times will not be the same because the most adaptive profiles vary with the values of the society and the historical era. An essay on personality dev…
Unlike generalized anxiety, phobias involve specific, identifiable but usually irrational fears. Phobias are common occurrences among a large segment of the population. People with phobias recognize that their fears are irrational, yet avoid the source to spare themselves of the resultinganxiety. Phobias are classified as disorders only when they interfere substantially with a person's dail…
Although people recognize the brain as the center of mental processes, this contemporary view has not always been accepted. Philosophers and scientists have proposed different ideas throughout history about the process of thinking that have since been rejected as inaccurate. One such rejected approach was phrenology. Phrenologists believed that our different mental capacities were controlled by sp…
Placebos are substances with no known pharmacological value that are given to members of a control group in an experiment. In studies determining the effectiveness of a particular drug, for example, the experimental group is given the drug being studied and the control group is given a placebo, which is made to look exactly like the actual drug. Neither group, nor the researchers, knows which rece…
While the term "play" may refer to an extremely varied range of activities, certain broad, defining characteristics have been noted. Perhaps the most basic one is that play is something that is not required. Although the enjoyment derived from it may be needed emotionally, no single play activity itself is necessary for survival. Thus, play is referred to as "autotelic"…
Among other principles, Freudian psychology states that there is a basic human tendency to seek pleasure and avoid pain. It arises from the desire for unrestrained expression of both the life instinct (Eros) associated with sexuality and the death instinct (Thanatos) associated with aggression and destructiveness. Freud described the pleasure principle in terms of the need to discharge or reduce t…
There is an obvious and necessary imprecision in this definition of the term pornography, in the sense that what is considered to be sexually obscene behavior, and, for that matter, what might sexually arouse an audience, vary quite widely from time to time, from place to place, and from individual to individual. Nearly all modern societies have laws that prohibit the possession or distribution of…
Power may be defined in both personal and interpersonal terms. In the first sense, it refers to one's physical, intellectual, or moral capacity to act. In the second, it denotes the ability to influence the behavior of others. Philosophers have often described power as an integral facet of human existence. Psychologist Harry Stack Sullivan (1892-1949) has claimed that power is a more crucia…
Sigmund Freud theorized that the human mind was divided into three parts: the conscious, preconscious, and unconscious. This schema first appeared in his earliest model of mental functioning, published in his classic work, The Interpretation of Dreams (1900). Freud believed that the preconscious functions as an intermediate or transitional level of the mind—between the unconscious and the c…
Prejudice has cognitive, affective, and behavioral components. Based on beliefs, it can affect one's emotions and behavior, sometimes leading to discrimination. Prejudiced beliefs primarily take the form of stereotypes, overall impressions based on the assumption that all members of a group possess similar attributes. Various theories have been proposed to explain the causes and dynamics of…
Premenstrual syndrome (PMS) exhibits both physiological and psychological symptoms. The primary physiological symptoms are water retention and bloating, slightly enlarged and tender breasts, and food cravings. Psychological symptoms include irritability and depression. The full range of symptoms that have been attributed to PMS is extremely broad: as many as 150 have been identified. Because the s…
Projective techniques involve asking subjects to interpret or fill in visual stimuli, complete sentences, or report what associations particular words bring to mind. Because of the leeway provided by the tests, subjects project their own personalities onto the stimulus, often revealing personal conflicts, motivations, coping styles, and other characteristics. The best known projective test is the …
The term psyche actually takes its meaning from ancient myth. In Roman mythology, Psyche represented the human spirit and was portrayed as a beautiful girl with butterfly wings. Psyche was a beautiful mortal desired by Cupid, to the dismay of Cupid's mother Venus. Venus demanded that her son order Psyche to fall in love with the ugliest man in the world. Cupid refused and loved Psyche himse…
The role of psychoactive drugs, also called psychotherapeutic agents or psychotropic drugs, in the treatment of mental illness is dependent on the disorder for which they are prescribed. In cases where mental illness is considered biological in nature, such as with a diagnosis of bipolar disorder or schizophrenia, pharmaceutical therapy with psychotherapeutic drugs is recommended as a primary meth…
Punishment is defined as the administration of aversive stimulus to reduce or eliminate unwanted behavior. It can be either physical or nonphysical. Punishment differs from negative reinforcement in that the latter increases the frequency of behavior by removing a negative event. Punishment can be as simple as giving electric shocks to lab rats to prevent them from touching a lever or as complex&#…
Research psychologists can collect two kinds of information: quantitative data and qualitative data. Quantitative data are often represented numerically in the form of means, percentages, or frequency counts. Such data are often referred to as "measurement" data, referring to the fact that we often like to measure the amount or extent of some behavior, trait, or disposition. For exam…
Throughout human history, people have tended to divide each other into groups. Most often, physical characteristics are used to distinguish between groups, and the groups are called races. Some people have long believed that many characteristics about a person could be determined by simply looking at the person's race. Intelligence is one trait that has been studied in an attempt to correla…
Racism is most commonly used to describe the belief that members of one's own race are superior physically, mentally, culturally, and morally to members of other races. Racist beliefs provide the foundation for extending special rights, privileges, and opportunities to the race that is believed to be superior, and to withholding rights, privileges, and opportunities from the races believed …
Rape is essentially an act of power and dominance. Although an estimated 15 to 40 percent of American women are victims of rape or attempted rape, men are raped as well. Women are more likely to be raped by someone they know; between 50 and 70 percent of all rapes occur within the context of a romantic relationship, and more than half the time the assault takes place in the victim's home. R…
First described in 1953 by Nathaniel Kleitman and Eugene Aserinsky, rapid eye movement (REM) sleep is also called active sleep because the EEG (electroencephalogram) patterns in this stage are similar to the patterns during the awake stage. The four stages of slow-wave, or non-REM, sleep are accompanied by deep breathing, a relatively slow heartbeat, and lowered blood pressure. In contrast, levels…
Several categories of reaction time, such as simple reaction time, have been established and studied in experimental psychology. In a simple reaction time experiment, the subject is presented with one simple stimulus, such as a light, and instructed to perform one simple response, such as pressing a button. In a discrimination reaction time experiment, the subject is presented with one of two or m…
Very often in Western culture, listening is considered to be the passive part of a conversation while speaking is seen as active. Reflective listening practices requires focus, intent, and very active participation. The term stems from work done by psychologist Carl Rogers who developed client-centered therapy. Rogers believed that by listening intently to the client, a therapist could determine b…
In a simple reflex, a sensory receptor initiates a nerve impulse in an afferent sensory nerve fiber which conducts it to the spinal cord. In the gray matter of the spinal cord, the afferent nerve impulse is fired over the synaptic gap to an efferent motor fiber which passes along the impulse to the appropriate muscle, producing the reflex. There are other reflexes which involve neural pathways con…
Rehabilitation begins once a debilitating condition has been evaluated and treatment is either in progress or completed. Impairments are evaluated for their effects on the individual's psychological, social, and vocational functioning. Depending on the type of disability involved, "self-sufficiency" may mean a full-time job, employment in a sheltered workshop, or simply an ind…
In classical (Pavlovian) conditioning, where the response has no effect on whether the stimulus will occur, reinforcement produces an immediate response without any training or conditioning. When meat is offered to a hungry dog, it does not learn to salivate, the behavior occurs spontaneously. Similarly, a negative reinforcer, such as an electric shock, produces an immediate, unconditioned escape …
Psychologists have long studied religion and religious practices. Using principles of traditional psychology, researchers try to understand religious experience, including prayer, cults, and mystical experiences. The study of religion and psychology began in the early twentieth century, but faded before it was revived in the 1980s, when the American Psychological Association began to formally inve…
Psychologists use a wide variety of techniques to answer research questions. The most commonly used techniques include experiments, correlational studies, observational studies, case studies, and archival research. Each approach has its own strengths and weaknesses. Psychologists have developed a diversity of research strategies because a single approach cannot answer all types of questions that p…
RNA consists of a five-carbon sugar (ribose), phosphate, and four nitrogenous bases (adenine, guanine, cytosine, and uracil). In an RNA molecule, the sugar and phosphate combine to form a structure to Computer-generated image of ribonucleic acid. (Photo by Ken Eward. National Audubon Society Collection/Photo Researchers, Inc. Reproduced by permission.) which the nitrogenous bases are attach…
In normal human adults, each hemisphere of the brain, working in concert with the other, performs certain types of functions more efficiently than the other. While the left-brain hemisphere is dominant in the areas of language and logic, the right-brain hemisphere is the center of nonverbal, intuitive, holistic modes of thinking. Each hemisphere mostly receives perceptions from and controls the ac…
In ancient times, there were rituals of scapegoating. A tribe or person would literally sacrifice an animal to the gods, or send an animal into the desert declaring that that animal was carrying away the tribe's sins. In today's culture, psychology uses the term to discuss certain forms of victimization. A particular child of an alcoholic family can be deemed the scapegoat, for insta…
The scientific method involves a wide array of approaches and is better seen as an overall perspective rather than a single, specific method. The scientific method that has been adopted was initially based on the concept of positivism, which involved the search for general descriptive laws that could be used to predict natural phenomena. Once predictions were possible, scientists could attempt to …
Security objects are items, usually soft and easily held or carried, that offer a young child comfort. Security objects are also referred to as attachment objects, inanimate attachment agents, nonsocial attachments, comfort habits, transitional objects, not-me possessions, substitute objects, cuddlies, treasured possessions, soothers, pacifiers, special soft objects, Linus phenomenon, and security…
The term self-actualization was used most extensively by Abraham Maslow, who placed it at the apex of his hierarchy of human motives, which is conceived as a pyramid ascending from the most basic biological needs, such as hunger and thirst, to increasingly complex ones, such as belongingness and self-esteem. The needs at each level must be at least partially satisfied before those at the next can …
Self-concept—the way in which one perceives oneself—can be divided into categories, such as personal self-concept (facts or one's own opinions about oneself, such as "I have brown eyes" or "I am attractive"); social self-concept (one's perceptions about how one is regarded by others: "people think I have a great sense of humor")…
Succeeding or failing to meet the standards, rules, and goals of one's group or society determines how well an individual forms relationships with other members of the group. Living up to one's own internalized set of standards—or failing to live up to them—is the basis of complex emotions. The so-called self-conscious emotions, such as guilt, pride, shame, and hubris, …
Psychologists who write about self-esteem generally discuss it in terms of two key components: the feeling of being loved and accepted by others and a sense of competence and mastery in performing tasks and solving problems independently. Much research has been conducted in the area of developing self-esteem in children. Martin Seligman claims that in order for children to feel good about themselv…
One's beliefs about other people determine how one acts towards them, and thus play a role in determining the behavior that results. Experiments have demonstrated this process in a variety of settings. In one of the best-known examples, teachers were told (falsely) that certain students in their class were "bloomers" on the verge of dramatic intellectual development. When the …
The most basic question of sex differences is whether the differences between the sexes are a result of our sex chromosomes, and genetic in nature, or did humans learn them from our social and cultural environments? This argument, usually referred to as the nature-nurture controversy, is one that is common in psychological work. Most psychologists attribute our differences to a combination of natu…
Men and women are different not only in anatomy, but also in terms of how they behave and in the interests they express. Certain behavioral differences are believed to be biologically determined. For example, the male sex hormone testosterone is believed to be the reason why males are considered more aggressive than females. However, many nonanatomical differences appear to be based on sex roles t…
Sexual abuse includes any sexual act or experience which is forced upon a person or which occurs as a result of coercion. In general, any sexual experience or exposure that occurs between a child and an older child, an adolescent, or an adult, for the gratification of the older individual, is considered to be sexual abuse. Sexual abuse includes rape, incest, inappropriate touching, exhibitionism, …
Components of identity include a sense of personal continuity and of uniqueness from other people. In addition to carving out a personal identity based on the need for uniqueness, people also acquire a social identity based on their membership in various groups—familial, ethnic, occupational, and others. These group identities, in addition to satisfying the need for affiliation, help people…
Sigmund Freud believed that human personality consisted of three components: the id, the ego, and the superego. The id is the part of the personality that includes such basic biological impulses or drives as eating, drinking, eliminating wastes, avoiding pain, attaining sexual pleasure, and aggression. The id operates on the "pleasure principle," seeking to satisfy these basic urges …
While sex is not necessary for an individual's survival, without it a species would cease to exist. The determinants of sexual motivation and behavior include an individual's physiology, learned behavior, the physical environment, and the social environment. A person's sex is determined at conception by whether one out of the 23 chromosomes in the father's sperm is eith…
Imagination involves the synthetic combining of aspects of memories or experiences into a mental construction that differs from past or present perceived reality, and may anticipate future reality. Generally regarded as one of the "higher mental functions," it is not thought to be present in animals. Imagination may be fantastic, fanciful, wishful, or problem-solving, and may differ …
While the incest taboo is nearly universal and exists in nearly all societies, notions of kinship vary greatly from culture to culture. Thus, some cultures would consider sexual relations between first cousins incest, while others would not. The same premise holds true for inter-course between a stepfather and stepdaughter. The very rare exceptions to incest, such as those found in ancient Egyptia…
Most people, from social recluses to the rich and famous, probably have experienced feelings of shyness at various times in their lives. Physiological symptoms may include blushing, increased heart rate, sweating, and shaking. Just as these outward manifestations vary in type and intensity from person to person, so do the inner feelings. Anxious thoughts and worries, low self-esteem, self-criticis…
In experimental research, psychologists create two or more groups that are as similar as possible except for a single change that the psychologist makes from one group to the next. That single element that varies across groups is called the independent variable. In more complex research, the experimenter may include more than one independent variable. In one experiment dealing with eyewitness test…
One of the early goals of psychologists was to measure the sensitivity of our sensory systems. This activity led to the development of the idea of a threshold, the least intense amount of stimulation needed for a person to be able to see, hear, feel, or detect the stimulus. Unfortunately, one of the problems with this concept was that even though the level of stimulation remained constant, people …
When a child uses inductive thinking or reasoning, he or she engages in the evaluation and comparison of facts to reach a conclusion. Inductive reasoning progresses from observations of individual cases to the development of a generality. (Inductive reasoning, or induction, is often confused with deductive thinking; in the latter, general principles or conditions are applied to specific instances …
When researchers measure a behavior, they often compare groups to determine whether they differ on that behavior. The ultimate goal is to determine whether the difference would occur if the measurements were administered a second time, or whether the difference is accidental and not likely to recur. The degree of reliability relates to the concept of significance level. The significance level refe…
A healthy adult sleeps an average of 7.5 hours each night and most people (approximately 95 percent) sleep between 6.5 and 8.5 hours. Tracking brain waves with the aid of electroencephalographs (EEGs), researchers have identified six stages of sleep (including a pre-sleep stage), each characterized by distinctive brain-wave frequencies. Stage 0 is the prelude to sleep, which is characterized by lo…
The term "inferiority complex" was coined in the 1920s by French psychologist Alfred Adler, a one-time follower of Sigmund Freud who became disenchanted with Freud's emphasis on the influence of unconscious factors as motivators in human behavior. While Adler subscribed to the notion that underlying motivations play a part in directing personality, he introduced the notion of …
The information-processing theory is associated with the development of high-speed computers in the 1950s. Researchers—most notably Herbert Simon and his colleagues—demonstrated that computers could be used to simulate human intelligence. This development led to the realization that computer-oriented information-processing models could provide new insight into how the human mind rece…
Olfaction is one of the two chemical senses: smell and taste. Both arise from interaction between chemical and receptor cells. In olfaction, the chemical is volatile, or airborne. Breathed in through the nostrils or taken in via the throat by chewing and swallowing, it passes through either the nose or an opening in the palate at the back of the mouth, and moves toward receptor cells located in th…
Social competence refers to the social, emotional, and cognitive skills and behaviors that children need for successful social adaptation. Despite this simple definition, social competence is an elusive concept, because the skills and behaviors required for healthy social development vary with the age of the child and with the demands of particular situations. A socially competent preschool child …
The insanity defense allows a mentally ill person to avoid being imprisoned for a crime on the assumption that he or she was not capable of distinguishing right from wrong. Often, the sentence will substitute psychiatric treatment in place of jail time. The idea that some people with mental illness should not be held responsible for crimes they commit dates back to the Roman Empire, if not earlier…
Human behavior is influenced by other people in countless ways and on a variety of levels. The mere presence of others—as co-actors or spectators—can stimulate or improve one's performance of a task, a process known as social facilitation (and also observed in non-human species). However, the increased level of arousal responsible for this phenomenon can backfire and create so…
Behavior is considered instinctive only if it occurs in the same form in all members of a species. Instincts must be unlearned and characteristic of a specific species. Animals provide the best examples of instinctive behavior. Birds naturally build nests without being taught and feed and protect their young in the exact same ways. Other animals, such as squirrels or dogs, behave in manners charac…
Our views of mental institutions are often colored by media's portrayal of them, such as in the movies One Flew Over the Cuckoo's Nest and Girl, Interrupted. With an emphasis on care and treatment, the best institutions offer emotionally disturbed people a better chance at life. They can learn new skills, improve behavioral and psychological problems, and develop healthier self-estee…
Researchers have confirmed the conventional wisdom that first impressions are important. Studies show that first impressions are easily formed, difficult to change, and have a long-lasting influence. Rather than absorbing each piece of new information about an individual in a vacuum, it is common for people to invoke a preexisting prototype or schema based on some aspect of the person (for example…
Instrumental behavior is a concept that grew out of the behavior therapy movement, originating in the 1950s with the work of H.J. Eysenck. Behavior therapy asserts that neuroses are not the symptoms of underlying disorders (as Sigmund Freud theorized), but are in fact disorders in and of themselves. Further, these disorders are learned responses to traumatic experiences in much the same way that a…
Several theories about intelligence emerged in the 20th century and with them debate about the nature of intelligence, whether it is hereditary, environmental or both. As methods developed to assess intelligence, theorizing occurred about the measurability of intelligence, its accuracy and this field known as psychometrics. As the 20th century drew to a close, publication of The Bell Curve by Rich…
Although intelligence quotient (IQ) tests are still widely used in the United States, there has been increasing doubt voiced about their ability to measure the mental capacities that determine success in life. IQ testing has also been criticized for being biased with regard to race and gender. In modern times, the first scientist to test mental ability was Alfred Binet, a French psychologist who d…
Holistic healthcare, the concept that the body is not just a collection of separate and distinct parts but rather an assemblage of interrelated components that form a unified whole, is at the root of interdisciplinary treatment. The holistic viewpoint is that mental health is related to and interdependent on physical well-being, and viceversa. An interdisciplinary treatment team has the ability to…
An interest inventory is a testing instrument designed for the purpose of measuring and evaluating the level of an individual's interest in, or preference for, a variety of activities; also known as interest test. Testing methods include direct observation of behavior, ability tests, and self-reporting inventories of interest in educational, social, recreational, and vocational activities. …
Special education refers to a range of services, including social work services and rehabilitative counseling, provided to individuals with disabilities from ages 3-21 through the public school system, including instruction given in the classroom, at home, or in institutions. Special education classes are taught by teachers with professional certification. Some teachers specialize in working with …
Individuals who are quiet, reserved, thoughtful, and self-reliant are often referred to as "introverts." They are likely to prefer solitary work and leisure activities. In comparison with extroverts, who draw most of their energy from social interaction and respond to external stimuli immediately and directly, introverts tend to mull things over before formulating a reaction, and the…
Speech perception, the process by which we employ cognitive, motor, and sensory processes to hear and understand speech, is a product of innate preparation ("nature") and sensitivity to experience ("nurture") as demonstrated in infants' abilities to perceive speech. Studies of infants from birth have shown that they respond to speech signals in a special way, sug…
Jealousy is a combination of emotional reactions, including fear, anger, and anxiety. Studies have shown that men and women tend to feel jealous for different reasons; for instance, physical attractiveness in a perceived rival is more likely to incite jealousy in a woman than in a man. Everyone occasionally experiences normal jealousy; caring about anyone or anything means that one will become unc…
Psychologists have demonstrated that even simple human tasks, like thinking of a word when viewing an object, involve separate subtasks within the brain. These smaller tasks involve identifying the object, assessing its use, remembering what other objects are related to it, determining how many syllables are in the word associated with the object, and so on. People do not realize the complexity of…
When we try to compare two different objects to see if they are the same or different on some dimension (e.g., weight), the difference between the two that is barely big enough to be noticed is called the just noticeable difference (JND). Just noticeable differences have been studied for many dimensions (e.g., brightness of lights, loudness of sounds, weight, line length, and others). The human se…
According to the Federal Bureau of Investigation (FBI) and the Centers for Disease Control (CDC), the arrest rate of American juveniles (persons 18 years of age or younger) committing violent crimes increased from 137 percent in 1965 to 430 percent in 1990. While teenagers are the population most likely to commit crimes, their delinquency is related to the overall incidence of crime in society: te…
Some people believe and perpetuate stereotypes about particular ethnic groups: Italians are emotionally sensitive, loud, and talk with their hands; Irish people drink too much; Germans are serious and intelligent. While such characteristics may apply to few members of that ethnic group, some people characterize all people in a certain group to share these traits. Psychologists have also noted the …
Kinesthesis refers to sensory input that occurs within the body. Postural and movement information are communicated via sensory systems by tension and compression of muscles in the body. Even when the body remains stationary, the kinesthetic sense can monitor its position. Humans possess three specialized types of neurons responsive to touch and stretching that help keep track of body movement and…
Stimulants are used for the treatment of certain psychiatric conditions and also used (and abused) for recreational purposes, enhanced levels of energy, and weight loss. They may be prescription or over-the-counter medications, illegal street drugs, or ingredients in commonly ingested substances, such as the caffeine in coffee or the nicotine in cigarettes. Whatever their form, stimulants increase…
While there is little consensus among psychologists about the exact definition of stress, it is agreed that stress results when demands placed on an organism cause unusual physical, psychological, or emotional responses. In humans, stress originates from a multitude of sources and causes a wide variety of responses, both positive and negative. Despite its negative connotation, many experts believe…
The term subliminal is derived from the Latin words sub (below) and limen (threshold). The threshold, in this case, is the threshold of conscious awareness. Can we be influenced by stimuli that are so faint or brief that we are unaware of their presence? In other words, can people be affected by invisible stimuli? This controversial notion has intrigued scientists and the public for decades. A pub…
The annual death toll from suicide worldwide is 120,000, and it is the eighth leading cause of death in the United States, accounting for one percent of all deaths. Between 240,000 and 600,000 people in the U.S. and Canada attempt suicide every year, and over 30,000 succeed. The suicide rate is three times higher for men than for women in the United States, although females make three times as man…
The superego is one of three basic components of human personality, according to Sigmund Freud. The id is the most primitive, consisting of largely unconscious biological impulses. The ego uses reality and its consequences to modify the behavior being urged by the id. The superego judges actions as right or wrong based on the person's internal value system. Freud believed that a child devel…
The study of psychology generally does not include any emphasis on these seemingly irrational beliefs that motivate behavior. Nevertheless, superstitious actions are common in our society. Avoiding walking under ladders in order to ward off disaster, crossing fingers for good luck, and knocking on wood surfaces to ensure continued prosperity or avoid tragedy are examples of commonplace superstitio…
Every thought, movement, and sensation occurs due to communication between different neurons, which provide information throughout the nervous system. Within a single neuron, information proceeds through electrical signals, but when information must be transmitted from one neuron to a succeeding neuron, the transmission is chemical. For two neurons to communicate, chemical messengers, or neurotran…
Taste, or gustation, is one of the two senses triggered by chemical stimuli (the other is olfaction). A person has approximately 10,000 taste buds. Most are on the tongue, but some are located in the back of the throat. Grouped together in bumps or papillae on the surface of the tongue, the taste buds contain receptors that respond to four basic tastes: sweet, salty, sour, and bitter. (It has also…
Individual variations in temperament are most readily observed in newborn babies. Even immediately after birth, some babies are calm while others cry a lot. Some respond favorably to being held while others squirm and protest. Some are soothed by soft music and others do not stop crying long enough to hear it. Because of these immediately observable variations, temperament is often considered a bi…
Psychologists have been interested in the factors that are important in behavior change and control since psychology emerged as a discipline. One of the first principles associated with learning and behavior was the Law of Effect, which states that behaviors that lead to satisfying outcomes are likely to be repeated, whereas behaviors that lead to undesired outcomes are less likely to recur. This …
In any group of people, there are those who step forward to organize people and events to achieve a specific result. In organized activities, leaders can be designated and, in informal contexts, such as a party, they may emerge naturally. What makes certain people into leaders is open to debate. Luella Cole and Irma Nelson Hall have written that leadership "seems to consist of a cluster …
The thalamus is a relatively large collection of cell body clusters shaped like two small footballs. It is involved in receiving sensory information from the eyes and other sense organs, processing that information, and then transmitting it to primary sensory zones in the cerebral cortex. The thalamus also processes pain signals from the spinal cord as well as information from different parts of t…
The sense of touch is located in the skin, which is composed of three layers: the epidermis, dermis, and hypodermis. Different types of sensory receptors, varying in size, shape, number, and distribution within the skin, are responsible for relaying information about pressure, temperature, and pain. The largest touch sensor, the Pacinian corpuscle, is located in the hypodermis, the innermost thick…
The left-brain hemisphere neurologically controls the right side of the body and is connected to the right-brain hemisphere by an extensive bundle of over a million nerve fibers called the corpus callosum. Scientific study of the brain hemispheres dates back to the 1800s. In the 1860s, French physician Paul Broca (1824-1880) observed speech dysfunction in patients with lesions on the left frontal …
Traits include such personality characteristics as introversion, aggressiveness, generosity, nervousness, and creativity. Systems that address personality as a combination of qualities or dimensions are called trait theories. The first comprehensive trait theory was that of Gordon Allport (1897-1967). Over a period of thirty years, Allport investigated over 18,000 separate traits, proposing severa…
Transference is the tendency for a client in psychotherapy, known as the analysand, to transfer emotional responses to their therapists that reflect feelings the analysand has for other significant people in his or her life. Transference often echoes clients' relationships with their parents or with other persons who played a central role in their childhood. They may become excessively depe…
The term libido, which Sigmund Freud used as early as 1894 and as late as the 1930s, underwent changes as he expanded, developed, and revised his theories of sexuality, personality development, and motivation. In Freud's early works, it is associated specifically with sexuality. Libido is central to the theory of psychosexual development outlined in Three Essays on the Theory of Sexuality (…
Transgender, or transsexualism, a condition in which the individual defines him or herself as male or female in opposition to their physical gender, or feels strongly that he or she wants to live as a member of the other gender, is rare. By some estimates, no more than 1 person in 350,000 believes he or she was born the wrong gender. As they progress through childhood, their inability to relate to…
Theories of localization first gained scientific credence in the 1860s with Paul Broca's discovery that damage to a specific part of the brain—the left frontal lobe—was associated with speech impairment. Other discoveries followed: in 1874, Carl Wernicke identified the part of the brain responsible for receptive speech (the upper rear part of the left temporal lobe, known as W…
In the 1970s, psychologists started investigating possible links between personality and health. Initial research seemed to indicate that persons with a type A Personality were at higher risk for coronary heart disease—a medical condition that consists of a narrowing of the blood vessels that supply blood to the heart. Type A people are achievement oriented, irritable, impatient with delays…
One of the highly developed abilities that humans and other animals possess is the ability to determine where a sensory input originates. The capacity to localize a sound, for example, depends on two general mechanisms. The first is relevant for low frequency (i.e., low pitch) sounds and involves the fact that sound coming from a given source arrives at our ears at slightly different times. The se…
Sigmund Freud assumed that the human mind was divided into three divisions: the id, ego, and superego, which, in turn, had both conscious and unconscious portions. The id, motivated by two biological drives—sex and aggression—operates according to the pleasure principle, seeking satisfaction and avoiding pain. Guided by the reality principle, the ego's goal is to find safe and…
Unconscious motivation plays a prominent role in Sigmund Freud's theories of human behavior. According to Freud and his followers, most human behavior is the result of desires, impulses, and memories that have been repressed into an unconscious state, yet still influence actions. Freud believed that the human mind consists of a tiny, conscious part that is available for direct observation a…
If a person with an internal locus of control does badly on a test, she is likely to blame either her own lack of ability or preparation for the test. By comparison, a person with an external locus of control will tend to explain a low grade by saying that the test was too hard or that the teacher graded unfairly. The concept of locus of control was developed by psychologist Julian Rotter, who dev…
Regarded as a universal human trait, the ability to think logically, following the rules of logical inference, has traditionally been defined as a higher cognitive skill. The field of cognitive child psychology was dominated for more than half a century by the Swiss philosopher and psychologist Jean Piaget, whose studies are considered fundamental. Piaget identified four stages of cognitive develo…
The high incidence of violence in the United States is of great concern to citizens, lawmakers, and law enforcement agencies alike. Between 1960 and 1991, violent crime in the U.S. rose over 370 percent, and over 600,000 Americans are victimized by handgun crimes annually. Violent acts committed by juveniles are of particular concern: the number of American adolescents arrested for homicide has in…
Researchers in such fields as developmental psychology use longitudinal studies to study changes in individual or group behavior over an extended period of time by repeatedly monitoring the same subjects. In longitudinal research, results are recorded for the same group of subjects, referred to as a cohort, throughout the course of the study. An example of a longitudinal study might be an examinat…
The human eye is sensitive to only a limited range of radiation, consisting of wavelengths between approximately 400 to 750 nanometers (billionths of a meter). How the eye works. (Hans & Cassidy. Gale Research. Reproduced with permission.) The full spectrum of visible color is contained within this range, with violet at the low end and red at the high end. Light is converted into neu…
There are many kinds of loss and each has its own kind of grief. People lose loved ones like spouses, partners, children, family members, and friends. Even pet losses can cause grief. Job or property loss can be painful. Mourning is the conventional cultural behavior for those experiencing a loss. Grief reactions are those personal reactions to a loss, independent of expected cultural standards. E…
Cannabis, in the form of marijuana, hashish (a dried resinous material that seeps from cannabis leaves and is more potent than marijuana), or other cannabinoids, is probably the most often used illegal substance in the world. In the United States, marijuana use became widespread among young people in the 1960s. By 1979, 68 percent of young adults between the ages of 18 and 25 had experimented with…
