In psychology, breaking complex things down into simple parts can be helpful for looking at behavior from a different perspective.

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Reductionism, or reductionist theory, is the idea that complicated behaviors and phenomena can be better explained by “reducing” them into small, simple pieces.

The goal of reductionism is to make sense of the world around us rather than simply getting lost in the details. However, reductionism may garner different opinions, depending on whom you ask.

Reductionist theory competes with holism, a contrasting idea that focuses on looking at something as a whole sum.

Some psychologists appreciate how reductionism can break down human behaviors and feelings into smaller components that might be more easily understood. For others, reductionism may seem like a failure in looking at a person or situation completely or holistically.

Reductionism is a philosophical theory hypothesizing that phenomena may be easier to understand when they are broken down — or reduced — into smaller parts.

It’s possible to apply the theory of reductionism to anything, such as:

  • explanations
  • other theories
  • problems
  • objects
  • meanings

Reductionist theory is used in many scholarly disciplines, including:

  • all sciences
  • mathematics and computer science
  • religion and theology
  • philosophy
  • linguistics

A benefit of reductionism is that this theory’s application may make very complex or intimidating problems more approachable. Reductionists argue that this could also help solve specific problems more easily.

Types of reductionism

Reductionism can be divided into three parts in philosophy:

  • Ontological reductionism: the belief that everything in the world is made up of only a few components
  • Methodological reductionism: an idea that everything in the world can be broken down and explained into the smallest possible components
  • Theory reductionism: a philosophical belief that special theories or sub-theories can be absorbed into a more general, overarching theory

The reductionist theory can be used in many fields of psychology. Reductionists use the theory’s basic framework to break down possible explanations for all types of psychological phenomena, such as personality or mental health conditions.

Some angles of reductionist theory applied to psychology might investigate factors such as:

  • physiological
  • behavioral
  • social
  • cognitive
  • sociocultural

Reductionism is commonly reflected in psychology, and there are numerous ways the theory can be applied to the discipline. Specific healing modalities and even entire branches of psychology can be described as “reductionist.”

Personality tests

Personality tests are a typical example of how reductionism can be applied to psychology.

Numerous personality tests have been developed over the years, with different tests focusing on specific aspects of the personality.

Some examples of popular personality tests include:

  • Myers-Briggs
  • Enneagram
  • The Minnesota Multiphasic Personality Inventory-2 Restructured Form (MMPI-2-RF)

The Myers-Briggs personality test is a particularly good example of reductionism within personality testing. This particular modality breaks down the personality into four parts, explaining these phenomena as four “dimensions” used to describe a “type” of individual.

These personality assessments typically include multiple-choice questions designed to determine socially related answers, such as how you may handle conflict or what job field would be best for you.

Cognitive psychology

Cognitive psychology is a branch of psychology that looks at how mental processes and patterns may lead to particular behaviors or experiences.

Approaching psychology from a cognitive perspective can be considered reductionism because it focuses only on cognition. However, centering on the mental aspect of psychology could potentially leave out other important factors that may explain psychological phenomena.


Behaviorism is a reductionist theory in psychology and sociology that focuses on how someone’s interactions with their environment might reinforce behavior, choices, and overall social learning.

Explaining most — if not all — of human behavior in terms of conditioning and reinforcement is a common example of the reductionist lens in behaviorism.

However, a major downfall of reductionism with behaviorist thought is that this may ignore other factors that could be as important as environment, such as cognition and physiology or biology.

A typical behaviorist may recommend only behavioral modifications to treat a condition instead of considering other options such as medication. This could be considered a reductionist approach, as well.

Commonly used terms relating to an individual’s behavior include:

  • stimulus
  • response
  • punishment as a basis


Also called physiological psychology, biopsychology is a branch of psychology that studies the brain-body connection, focusing on biological factors. This is considered a reductionist interdisciplinary study of psychology because it considers only one essential part of the human experience.

In approaching mental health conditions and other psychological phenomena, biopsychology may highlight only physiological explanations, such as:

  • genes
  • assigned gender at birth
  • brain structure

A biopsychologist might exclusively suggest medications or treatments that could treat certain conditions at their physiological level. This can also be considered a reductionist approach to treatment.

Holism is a contrasting philosophical theory that is considered the antithesis of reductionism. The theory of holism is based on the idea that it is more effective and accurate to examine complex phenomena as a whole rather than breaking them down into less-complicated pieces.

Holism’s purpose is to look at all parts of something together, studying how each factor might fit together to make a sum whole. Holism acknowledges that each singular factor has its purpose, but how each interacts with one another may be more important.

Some scientists and researchers prefer holism over reductionism. Many argue that reductionism may risk oversimplification of key details, potentially devaluing the overall view.

In psychology, many disciplines of study are considered holist, including:

  • social
  • humanistic
  • positive

These branches of psychology view people and concepts as whole experiences rather than focusing on particular facets.

Reductionism is a philosophical theory used in many scientific disciplines, including psychology. It is based on the idea that all phenomena can be reduced into smaller aspects, including your behavior and feelings.

With reductionism, breaking down complex problems could simplify the process of examining and solving them. This framework can be applied to psychology as an approach to investigating and treating mental health conditions.

However, not everyone agrees that reductionism is the best way to look at things. Some researchers and scientists argue that the reductionist theory may risk gaps in information and knowledge by oversimplifying complex topics.

Holism, a competing theory, suggests investigating phenomena as a whole sum of its parts is a more effective and accurate way to solve problems.

Ultimately, there are pros and cons to both theories, and each can be quite useful. Whether you choose to apply a reductionist or holist lens to an issue largely depends on the topic or problem.