Psychology

Psychology is the scientific study of the mind and behavior. It looks at how humans and animals act, both conscious and unconscious thoughts, and mental processes such as thoughts, feelings, and motives. It is a broad subject that sits between the natural and social sciences. For other uses of the word, see Psychology (disambiguation). Psychology is not the same as physiology.

A person who works in psychology, either as a helper or a researcher, is called a psychologist. Some psychologists are also behavioral or cognitive scientists. Some study how the mind works in a single person and in groups of people, in social behavior. Others study the body and brain processes behind thinking and behavior. Biological psychologists try to understand how brains work as a whole, which connects their work to neuroscience. As social scientists, psychologists want to understand how individuals and groups behave.

Psychology is a field that draws on many other subjects. It studies how we perceive the world, how we think (cognition), how we pay attention, how we feel (emotion), intelligence, subjective experiences, motivation, how the brain works, and personality. Psychologists also study interpersonal relationships, psychological resilience, family resilience, and other topics within social psychology. They also think about the unconscious mind. Research psychologists use empirical methods to find causal and correlational connections between variables involving the mind and society. Some clinical and counseling psychologists use symbolic interpretation, though not all do.

Psychological knowledge is often used to help people with mental health problems, and it is also used to understand and solve problems in many parts of life. Psychology aims to help society. Many psychologists help people directly, using psychotherapy in clinics, counseling offices, or schools. Others carry out scientific research on many topics about the mind and behavior, usually at universities, medical schools, or hospitals. Another group works in industrial and organizational settings, and others work on human development, aging, sports, health, forensic science, education, and the media.

Etymology and definitions

The word psychology comes from the Greek word psyche, which means spirit or soul. The end of the word comes from -logia, which means "study" or "research." The word was first used during the Renaissance. The Latin form psychiologia was first used by the Croatian humanist and Latinist Marko Marulić in his book Psichiologia de ratione animae humanae (Psychology, on the Nature of the Human Soul) in the years 1510–1520. The earliest known use of the word psychology in English was by Steven Blankaart in 1694, in The Physical Dictionary. It said that Anatomy studies the body, and psychology studies the soul.

The Greek letter Ψ (psi), the first letter of psyche, is often linked with psychology. In 1890, William James described psychology as "the science of mental life, both of its thoughts and actions and the reasons behind them." This idea was used for many decades. However, in 1913 John B. Watson challenged it. He described psychology as a science of behavior, based only on things that can be observed and tested, like other branches of natural science. He used a methodological behaviorist view, and he said its goal is "the prediction and control of behavior." Since James's definition, the word has more strongly suggested scientific experiments. Folk psychology is the understanding that ordinary people have of the mental states and behaviors of others. This is different from the understanding of psychology professionals.

History

Main article: History of psychology

For a chronological guide, see Timeline of psychology.

People in ancient Egypt, Greece, China, India, and Persia studied the mind through philosophy. Greek thinkers such as Plato and Aristotle wrote about how the mind works. The doctor Hippocrates taught that mental disorders had physical causes, not supernatural ones. In China, thinkers such as Laozi and Confucius, along with Buddhism, shaped early ideas about the mind. Later, Enlightenment thinkers in Europe began to treat psychology as its own field of study. At first, many people did not think the mind could be studied through experiments. Over time, scientists started testing ideas about how we notice things and how we act in laboratories. Wilhelm Wundt set up a psychology laboratory at Leipzig University, which helped bring experimental psychology to the world.

Psychology then spread to many countries, including the United States. New schools of thought appeared, such as Gestalt psychology, which holds that people experience things as whole pictures. Psychologists also studied learning. Ivan Pavlov discovered a learning process in dogs that was later called "classical conditioning." During World War I and World War II, governments and armies paid for psychology research. Women also made important contributions to the field, including Anna Freud, Mary Ainsworth, and Martha Bernal, who was the first Latina woman to earn a Ph.D. in psychology.

Wilhelm Wundt (seated), a German psychologist, with colleagues in his psychological laboratory, the first of its kind, c. 1880

Main articles: List of women psychologists and Female psychology

Disciplinary organizations

In 1920, Édouard Claparède and Pierre Bovet started a group for applied psychology. It later became the International Association of Applied Psychology, which is considered the oldest international psychology group. In 1941, female psychologists in the U.S. formed their own group because men held most of the power in the field. Other groups, such as the Association of Black Psychologists, were formed so that non-European racial groups would be included. The International Union of Psychological Science (IUPsyS) was founded in 1951 under UNESCO. It is a worldwide group of national psychology societies. The American Psychological Association has 54 divisions. These include the Society for the Psychological Study of Social Issues and the American Psychology–Law Society. The Interamerican Psychological Society, founded in 1951, works to promote psychology across the Western Hemisphere.

Early experimental psychologists kept their work separate from parapsychology, which was popular in the late 1800s. Topics like hypnotism and psychism were also discussed at early meetings. By about 1905, though, people working in these areas had been pushed out of the field. For a long time, psychology has had to answer the claim that it is a "soft" science. In 1962, philosopher of science Thomas Kuhn said that psychology did not yet have the shared big theories found in fields like chemistry and physics. Critics also said that because some research uses self-reports, psychology cannot be fully objective. Feminist critics argued that the field's idea of objectivity hid the views of mostly male researchers. One scholar claimed that psychological research had supported a patriarchal agenda.

Major schools of thought

Neuropsychology and Neurosciences

Main articles: Neuropsychology and Neurosciences

Neuropsychology studies how the brain and behavior are connected. It looks at how certain brain regions help with memory, language, attention, and feelings. Researchers learn a lot by studying people who have had brain injuries or neurodegenerative diseases.

Comparative and Evolutionary

Main articles: Comparative psychology and Evolutionary psychology

Evolutionary psychology suggests that many human thoughts and behaviors developed through natural selection over the course of human history. Comparative psychology studies behavior and mental processes across different species. It traces its roots to the work of Charles Darwin.

Behaviorist

Main articles: Behaviorism, Psychological behaviorism, and Radical behaviorism

Behaviorists believe that much of human and animal behavior is learned. They developed behavior modification to help people replace unwanted behaviors with helpful ones. Important figures include Ivan Pavlov and B.F. Skinner. Later, Noam Chomsky criticized behaviorism, and this made it less important within psychology.

Cognitive

Main article: Cognitive psychology

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The Stroop effect is the fact that naming the color of the first set of words is easier and quicker than the second set.

Cognitive psychology studies mental processes such as perception, attention, memory, and problem solving. In the 1950s, it became a major part of psychology and grew into the wider field of cognitive science. Researchers also study cognitive bias, which is a kind of unhelpful thinking. Ideas from behaviorism and cognitive psychology were combined to form cognitive behavioral therapy.

Main article: Social psychology

Psychoanalytic

Main articles: Psychodynamics and psychoanalysis

Psychoanalysis is a set of ideas and methods that aim to explore the unconscious mind. It began in the 1890s with Sigmund Freud. Many later thinkers, including Carl Jung and Anna Freud, developed their own ideas. Some critics say psychoanalysis cannot be tested or proven wrong, so they do not think it is truly scientific.

Existential-humanistic

Main articles: Existential psychology and Humanistic psychology

Humanistic psychology began in the 1950s as a response to behaviorism and psychoanalysis. It focuses on the whole person, free will, and self-actualization. Abraham Maslow and Carl Rogers were among its founders. Later, positive psychology studied what helps people feel happy and well.

Existential psychology focuses on the meaning of life and the choices people make. Viktor Frankl used his own experiences to create logotherapy, which focuses on searching for meaning in one's life.

Themes

Main article: Personality psychology See also: Unconscious mind § Psychology Main article: Motivation Main article: Developmental psychology Main article: Behavioural genetics

Psychologists study personality. Personality is the set of patterns in how people behave, think, and feel, and these patterns tend to last over time. Different groups of psychologists have different ideas about personality. Freud said that personality comes from three parts working together: the id, ego, and super-ego. Trait theorists describe personality using key traits. The Big Five became an important trait theory starting in the 1980s.

Psychologists also study the unconscious mind. This is the part of the mind that we are not aware of, but it may still affect our thoughts and actions. Freud made this idea popular. Pierre Janet spoke of a subconscious mind. Some experiments suggest that the brain begins to consider taking actions before we become aware of them. Researchers John Bargh, Daniel Wegner, and Ellen Langer describe free will as an illusion.

Motivation is the study of why people and animals start, continue, or stop a behavior. Animals are often motivated by hunger, thirst, and fear. Humans seem to have a more complex set of motivations.

Developmental psychology is the study of how people's thoughts, emotions, and behaviors change over their lives. It began mainly with the work of Jean Piaget. Today it studies many stages of life, from babyhood to old age. Psychologists in this field often study children through games and observations. The games are fun for the child and useful for science.

The study of genes and environment looks at how both shape psychological traits. These two influences are often mixed together. To tell them apart, researchers use methods such as twin studies and adoption or cross-fostering studies. Research has found that many psychological traits are polygenic. This means that many genetic variants, each with a small effect, contribute to them.

Applications

Further information: Outline of psychology, List of psychology disciplines, Applied psychology, and Subfields of psychology

Psychology has many subfields. Each one studies the mind and behavior in its own way. Psychological testing is very old. It goes back to 2200 BCE, when examinations for the Chinese civil service were used. Later, Francis Galton helped create modern mental testing, which is also called psychometrics. Today, many people of all ages take mental tests in Western societies. Clinical psychology is the largest area of psychology. It helps people understand, prevent, and ease mental illness and emotional distress.

See also: Psychometrics and social statistics

Research methods

Main articles: Psychological research and List of psychological research methods

Many psychologists use numbers and statistics to test ideas. Quantitative psychological research often uses randomized and controlled experiments in laboratories. These experiments can only study a small range of short-term events. Some psychologists use less strictly controlled but more ecologically valid field experiments, which take place in real-life settings. In a true experiment, people are randomly placed into different groups. This helps researchers make strong claims about cause and effect. Researchers change one or more independent variables and measure the results. Other methods include surveys, observational studies, and longitudinal studies that follow the same people over time. Meta-analysis combines the results of many studies. Psychologists also study the brain with tools such as the electroencephalogram and functional magnetic resonance imaging. They also use computer simulation to model behavior.

Fewer psychologists use qualitative research. This can involve interviews, questionnaires, and first-hand observation. This type of research helps explain thoughts, feelings, and behaviors. It can also help researchers understand why some programs succeed and others fail. Psychologists also study animals to learn about human behavior, since animals can be easier to control in experiments. Sometimes psychologists watch people in everyday life through naturalistic observation. Finally, program evaluation checks whether projects, policies, and programs are working as intended.

Contemporary issues

Further information: Replication crisis § In psychology

Further information: Misuse of statistics and Misuse of p-values

Metascience is the study of science itself, using scientific methods. It has found some problems in psychology research. Some studies have shown bias, weak reproducibility, and misuse of statistics. In 1959, statistician Theodore Sterling found that 97% of the psychology studies he looked at supported their starting ideas. This may be a sign of publication bias. Later, Fanelli (2010) found that psychiatry and psychology studies confirmed their expected results much more often than studies in fields like space science or geosciences.

Many well-known findings in social psychology have not been repeated successfully. This is called the replication crisis. A Reproducibility Project from the Center for Open Science found that many highly publicized psychology findings could not be repeated. To help, 295 journals have adopted result-blind peer review. In this method, studies are judged by their planned methods rather than their results. Some critics also think statistical hypothesis testing is used the wrong way. In 1994, Jacob Cohen wrote that psychologists often confuse statistical significance with practical importance. Some psychologists now also use effect size statistics.

In 2010, Henrich and colleagues pointed out that many psychology studies use people from "WEIRD" ("Western, Educated, Industrialized, Rich, and Democratic") societies. These groups make up only a small part of the world's population. Researchers such as Arnett said this is a serious problem, because results from these groups may not apply everywhere. Starting in 2020, researchers who study non-human behavior have also started to notice that their conclusions might be affected by STRANGE bias. Some people also worry that mental health training programs are teaching fewer scientific skills. They also say that some unsupported practices, such as facilitated communication for infantile autism, body work, rebirthing, and reparenting, may be doubtful or even harmful, even though they are popular.

Ethics

Ethical rules for psychology have changed over time. Some famous studies from the past are now seen as unethical and against established codes, such as the Canadian Code of Conduct for Research Involving Humans and the Belmont Report. After World War II, the Nuremberg Code was created because of harmful experiments done by the Nazis. Later, most countries and science journals adopted the Declaration of Helsinki. In the U.S., the National Institutes of Health set up the Institutional Review Board in 1966. In 1974, it adopted the National Research Act. These rules encouraged researchers to get informed consent from people who take part in studies. Several questionable studies helped lead to this rule. They include the MIT-Harvard Fernald School radioisotope studies, the Thalidomide scandal, the Willowbrook hepatitis study, Stanley Milgram's studies of obedience to authority, and the Stanford Prison Experiment.

The ethics code of the American Psychological Association began in 1951. It has guided licensing laws in most American states. Its five general principles encourage psychologists to do no harm, to be responsible and honest, to be fair, and to respect people's rights and dignity. Psychologists must take extra care to protect groups such as children and people in prison. Informed consent means that a patient or research subject understands a procedure and freely chooses to take part. Psychologists must also keep patients' information private. They must avoid inappropriate relationships with patients. University ethics committees check research plans, and a study cannot go ahead without their approval. These committees also oversee animal research. Animal research is only accepted when the benefits outweigh the harm to the animals.

In the 1970s, comparative psychologist Harry Harlow faced strong criticism for his isolation experiments on rhesus macaque monkeys at the University of Wisconsin–Madison. The experiments aimed to create an animal model of clinical depression. In 1974, American literary critic Wayne C. Booth wrote that Harlow's work showed that social creatures can be harmed when their social bonds are broken.