What Is a Theory?

A theory describes a behavior and make predictions about future behaviors. khoa vu/Moment/Getty Images

The term theory is used with surprising frequency in everyday language. It is often used in to mean a guess, hunch, or supposition. You may even hear people dismiss certain information because it is "only a theory." It is important to note as you study psychology and other scientific topics, that a theory in science is not the same as the colloquial use of the term.

What Exactly Is a Theory?

A theory is a based upon a hypothesis and backed by evidence.

A theory presents a concept or idea that is testable.

In science, a theory is not merely a guess. A theory is a fact-based framework for describing a phenomenon. In psychology, theories are used to provide a model for understanding human thoughts, emotions, and behaviors.

A psychological theory has two key components:

  1. It must describe a behavior
  2. It must make predictions about future behaviors

Examples of Psychology Theories

Throughout psychology's history, a number of theories have been proposed to explain and predict various aspects of human behavior. Some of these theories have stood the test of time and remain well-accepted today. Others have not held up under close scientific scrutiny and may have been rejected altogether or only partially accepted by researchers today.

If you are looking for an example of a psychological theory, consider the following:

Each theory has helped contribute to our knowledge base of the human mind and behavior. Some theories such as classical conditioning are still well-accepted today. Others, like Freud's theories, have not held up so well and have been mostly replaced by new theories that better explain human development.

Types of Psychology Theories

There are many psychology theories, but most can be categorized as one of four key types:

Developmental Theories

Developmental theories provide a set of guiding principles and concepts that describe and explain human development. Some developmental theories focus on the formation of a particular quality, such as Kohlberg's theory of moral development. Other developmental theories focus on growth that happens throughout the lifespan, such as Erikson's theory of psychosocial development.

Grand Theories

Grand theories are those comprehensive ideas often proposed by major thinkers such as Sigmund Freud, Erik Erikson, and Jean Piaget.

Grand theories of development include psychoanalytic theory, learning theory and cognitive theory. These theories seek to explain much of human behavior but are often considered outdated and incomplete in the face of modern research. Psychologists and researchers often use grand theories as a basis for exploration, but consider smaller theories and recent research as well.


Mini-theories describe a small, very particular aspect of development. A mini-theory might explain relatively narrow behaviors, such as how self-esteem is formed or early childhood socialization. These theories are often rooted in the ideas established by grand theories, but they do not seek to describe and explain the whole of human behavior and growth.

Emergent Theories

Emergent theories are those that have been created relatively recently and are often formed by systematically combining various mini-theories. These theories often draw on research and ideas from different disciplines but are not yet as broad or far-reaching as grand theories.

The sociocultural theory proposed by theorist Lev Vygotsky is a good example of an emergent theory of development.

Reasons to Study Psychology Theories

In your psychology courses, you may find yourself questioning how necessary it is to learn about different psychology theories, especially those that are considered inaccurate or outdated. However, all of these theories provide valuable information about the history of psychology, the progression of thought on a particular topic and a deeper understanding of current theories.

By understanding how thinking has progressed, you can get a better idea not only of where psychology has been, but where it might be going in the future.

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