Psychology: Definition, Theories and Applications


Psychology is a field concerned with explaining, predicting, and improving how human beings act. Psychology helps people to attain a better understanding of themselves as well as others. While the main goal of psychology is to understand the mind and behavior, it is also used to help people improve various aspects of their lives. William Wundt is considered the father of psychology since he established the first laboratory to study mental states from a scientific viewpoint (Kalat, 2016). The field of psychology applies the scientific method to study the human mind and behavior. There are many approaches to psychology including biological, cognitive, social, and cultural. Similarly, there are numerous branches of psychology which have their various applications in society. This research paper provides a general overview of psychology and considers some of its introductory topics.

Advancement of Psychology

One of the most important questions in psychology is how to advance the field. Some people believe that psychology is merely a collection of beliefs and disregard it as unscientific. However, psychology is advanced through the scientific method, which is the step-by-step process of determining whether a relationship exists between two or more variables (Phan & Ngu, 2019). Psychologists usually propose explanations for and theories about human behavior. They then test those theories through scientific methods and determine whether their theories were correct or incorrect. In this way, psychology differs from the everyday observations and judgments that people make about social phenomena. It is essential to note that some of the pioneering concepts of psychology were dropped because they lacked scientific basis (Jhangiani et al., 2019). For instance, Sigmund Freud’s theory of the oedipal complex, the theory that adolescent boys are attracted to their mothers, is largely unscientific and has been abandoned. Psychology differentiates itself from pop-psychology through rigorous application of the scientific method.

The scientific method of advancing knowledge entails a number of steps. First, a researcher has to make an observation that piques their interest. This then becomes their subject of study and they formulate a research question around it. Second, the researcher will form a hypothesis about the topic under study. For instance, they may hypothesize that children from a two-parent household perform better in school in comparison with those from a one-parent household. Third, they would collect data using appropriate methods and use the data to test the formulated hypothesis (Jhangiani et al., 2019). Fourth, the researcher examines the results obtained and makes a conclusion about whether their hypothesis was correct. Finally, the researcher reports the results by publishing their findings, which enables other psychologists to replicate the study in future. In general, the scientific method is important to psychology because it differentiates objective conclusions from subjective or biased observations.

Theories of Psychology

The theories of psychology are also referred to as approaches or perspectives to psychology. The main perspectives include cognitive, behavioral, psychodynamic, humanistic, social, cultural, and biological (Phan & Ngu, 2019). Cognitive psychology attempts to understand the internal thought processes. It studies cognition to determine how thoughts influence actions. Cognitive psychology examines memory, perception, attention, creativity, reasoning, language, and problem-solving, among other mental processes. Behavioral psychology studies human behavior and deemphasizes unobservable processes such as thinking. For instance, this theory of psychology studies how behavior can be influenced by punishment or reinforcement. Psychodynamic psychology is one of the earliest theories, and it was advanced by Sigmund Freud. It emphasizes the role of early childhood experiences and the unconscious mind in explaining human behavior and treating mental conditions. The theory is not prominent in the modern era but had a large influence in the development of psychology.

The humanistic perspective, also known as positive psychology, posits that all human beings strive to become the best version of themselves. Psychologists Carl Rodgers and Abraham Maslow contributed heavily to this field (Phan & Ngu, 2019). For instance, the latter developed the Maslow’s hierarchy of needs. This model proposes that human beings have various categories of needs which motivate their behavior. Social psychology is a field which studies how individuals behave in the presence of others. For instance, a social psychologist could try to understand why a person, when in the presence of others, agrees to do something they would otherwise not consider. Cultural psychology studies the influence of culture on behavior. For instance, people in an individualistic culture such as that of the US have different social norms from those in a collectivistic culture such as Japan. Finally, biological psychology considers the influence of biology on behavior. For instance, a psychologist could propose that schizophrenia is caused by too much dopamine in the brain. It important to note that many psychologists take multiple perspectives to get a holistic understanding of the human mind and behavior.

Branches and Applications of Psychology

Many people assume that psychology is concerned with mental health only, but there are numerous branches or subfields of psychology. Nevertheless, clinical and counseling psychology is the largest field and has numerous professionals (Kalat, 2016). While clinical psychologists study behaviors that are considered abnormal, counseling involves working with people undergoing emotional or mental stress. For instance, a clinical psychologist studies mental disorders such as bipolar disorder, post-traumatic stress disorder, depression, and schizophrenia. They then use psychotherapy to develop a course of treatment for their patient. On the other hand, a counselor listens to and guides a person as they navigate life situations such as divorce, loss of employment, discrimination, and grief. Developmental psychology is concerned with the changes that occur during the life of a human being. For instance, a parent could consult a developmental psychologist to know if their child is developing at a normal rate. Developmental psychologists are concerned with the signs that show a person has achieved a given hallmark expected of their age.

Another branch of psychology is consumer psychology, which studies how human beings make decisions about what to buy. For instance, a consumer psychologist may posit that people are drawn to foods sold in yellow packets. This helps companies know how to appeal to consumers, and therefore, how to customize their products and marketing techniques (Phan & Ngu, 2019). Organizational or occupational psychology is a specialty that studies work performance. For instance, a psychologist in this field may help an organization determine how to improve employee morale. To do this, they would employ the various theories of motivation. For instance, one many hypothesize that a company’s employees are underperforming because the company does not pay them enough to meet their needs according to the Maslow’s hierarchy. They can also help increase employee retention as well as efficiency in production. Sport psychology is a branch of psychology which seeks to explain the factors that affect performance in physical activity. For example, a sport psychologist can help athletes improve their individual or group performance. Although it is mainly used to boost sport performance, it has applications in other situations that require physical perseverance and mental resilience.

Psychology can also be applied in law enforcement via a branch known as forensic psychology. For instance, a forensic psychologist could give expert testimony to help the court make its decision. They can also aid in matters such as determining whether a person is fit to stand trial. Forensic psychologists give insight into why people display aggression, commit crimes, and engage in other behaviors that deviate from social norms. Neuropsychology is a branch that combines neurology and psychology to understand disorders of the nervous system (Phan & Ngu, 2019). Psychologists in this field study the brain structure and the functions of the various components. Consequently, this helps them understand and develop treatment for neurological conditions such as dementia, autism spectrum disorders, seizures, and attention deficit hyperactivity disorder. There are many other branches of psychology and their corresponding applications. A psychologist can specialize in any of the fields discussed.


In summary, psychology is a field of study that is interested in how human beings think and act. It relies on the scientific method to advance knowledge, which makes psychology a scientific study. There are numerous perspectives that psychologists take to explain why human beings act the way they do. Examples of these theories include behavioral, cognitive, social, humanistic, and psychodynamic. There are also numerous branches of psychology, which show the many ways the field can be used to improve life. Applications range from improving work performance to catching criminals. Ultimately, the goal of psychology is to study the human mind and behavior in an attempt to improve the wellbeing of individuals and that of society.


Jhangiani, R. S., Chiang, I. C. A., Cuttler, C., & Leighton, D. C. (2019). Research methods in psychology. Kwantlen Polytechnic University.

Kalat, J. W. (2016). Introduction to psychology. Cengage Learning.

Phan, H. P., & Ngu, B. H. (2019). Teaching, learning and psychology. Oxford University Press.

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