What Is Reductionism?

How psychologists use reductionism to understand behavior

Reductionism is a theory in psychology centered on reducing complex phenomena into their most basic parts. It is often contrasted with holism, which is focused on looking at things as a whole.

The purpose of reductionism is to simplify psychological events and processes by looking at their smallest elements, thus “reducing” something rather complex into its most simple.

These two approaches are often pitted against one another. Where a reductionist would propose that the best way to understand something is to look at what it is made up of, a holist would argue that the sum product is more than simply the sum of its parts.

A Closer Look

Reductionism is an approach that is used in many disciplines, including psychology, that is centered on the belief that we can best explain something by breaking it down into its individual parts.

If you want to understand something, the reductionist approach would propose simply taking a look at each of its constituent pieces. If you wanted to understand a car, for instance, you would look at each part of the engine, body, and interior.

The big question in psychology is not whether or not reductionism has value—it is to what extent it can be useful.

It can be quite helpful in some types of research, but in many cases, the sum is much more than simply the total of its pieces. The complete item in question has what are known as emergent properties that are simply not present in its smaller pieces.

In the example of a car, looking at each individual component can tell you a great deal about the mechanics of the vehicle, but you will not know other details such as how comfortable the interior is, how smooth the ride is, or how good the gas mileage will be until the pieces are reassembled back into the whole.

How It's Used

When trying to understand human behavior, scientists using this perspective would say that the best way to understand it would be to look at the parts that make up each system of the human brain and body. By knowing how each part works, reductionists suggests that we can then form an understanding of the whole based on what we know about each element that contributes to how the whole functions.

Within psychology, there also exist different areas in which reductionism operates.

At its most basic level, reductionism might focus on the neurons and neurological processes that impact how people think and act.

Another very basic level of reductionism would involve looking at DNA and genes to determine how human behaviors are influenced by genetics. This level of reductionism might also focus on the different parts of the brain and how each structure in the brain affects different processes and behaviors.

Another level of reductionism would focus on how behavior can be reduced to stimulus-response cycles (ie, behaviorism).

The cognitive approach would also represent another aspect of reductionism centered on understanding how people gather, store, process, and use information.

Higher levels of the reductionist approach might take a broader look at how specific things such as social interactions and culture impact how people think and act.

As you can see in each of these examples, reductionism involves taking psychological topics and breaking it down into a much more narrow focus.


So why would researchers choose to take a reductionist approach when looking at different psychological phenomena? While this process often involves oversimplifying things, there are reasons why reductionism can be useful.


One of the major benefits of reductionism is that it allows researchers to look at things that can be incredibly varied and complex such as the human mind and behavior, and break them down into smaller parts that are easier to investigate. It allows researchers to focus on a specific problem.

For example, researchers might utilize the reductionism approach when studying a psychiatric condition such as depression. Rather than trying to account for all of the many different forces that may contribute to depression, a reductionist perspective might suggest that depression is caused by biological processes within the body.

Make the Complicated Less Intimidating

When approaching a truly difficult problem, it can be all too easy to become overwhelmed by all the questions and information that are available. When studying psychological issues, for example, researchers might struggle to even form a basic hypothesis unless they find some way to focus their attention on a very small aspect of a phenomenon.

While this point of view neglects other factors that might contribute, such as genetics, social relationships, and environmental variables, it gives researchers a more narrow focus of their studies. By using reductionism to simplify what they want to study, researchers can explore a component is much greater depth.


While reductionism has some important benefits, it also has a few significant downsides that should be noted.

Ignores All Factors Contributing to a Problem

The clear downside of reductionism is that it is so totally focused on the smaller elements that contribute to a phenomenon that it fails to account for other forces that might play a role as well.

In our above example, researchers taking a biological approach for explaining depression might focus their studies on chemical reactions and balances within the body that contribute to symptoms of depression. While this type of research might lead to important medical advances in the treatment of depression, it excludes other variables such as cognitions, hereditary influences, personal problems, substance abuse, and other variables.

Does Not Account for the Whole

While reductionism can lead to exploring components of a phenomenon in greater depth, it also misses how these variables interact with one another. Few things have only one simple cause. Reductionism might allow researchers to look at each component individually, but it does not really explore how each of these smaller elements work together.

Complex systems are dynamic and always changing, and it is often by looking at how things work together as a whole that we can gain a clearer picture of how something works.

Examples in Psychology

There are a number of different approaches to psychology that are reflective of a reductionist approach to science. These include:


The biological approach to psychology is centered on understanding how the underlying biological processes contribute to human behavior. This represents a type of reductionism because researchers are focused on a smaller part of the human experience.

When approaching a psychological condition, for example, biopsychologists would suggest that the problem is the result of a biological process in the brain and body. To treat the condition, they would recommend medications that treat the problem at the physiological level.


The behaviorist approach to psychology focuses on how interactions with the environment contribute to learning and human behavior. At its strictest, behaviorism suggests that all human behaviors can be thought of in terms of conditioning and reinforcement. This reductionism approach ignores other factors such as cognitions and biology in favor of simply focusing on environmental influences.

A behaviorist might look at a psychological condition in terms of how present behavior has been caused by past learning. To treat the condition, a behaviorist would recommend utilizing behavior modification techniques to weaken old associations and form new ones.

Cognitive Psychology

The cognitive approach focuses on studying how internal mental processes can be carefully and objectively studied. This approach is reductionist because it focuses only on cognitions and neglects other factors that might contribute to a behavior.

A cognitive psychologist might explain a psychological condition in terms of the underlying thought patterns that contribute to the person’s feelings and behaviors. They might recommend a treatment approach centered on changing the unhealthy cognitions in order to replace them with more positive, realistic ones.

Reductionism vs. Holism

The reductionist approach to science is frequently contrasted with the holistic approach, which approaches things as a whole rather than focusing on the individual parts. The holistic approach does not discount the importance of each individual component but instead suggests that understanding the whole requires looking at how these parts work on different levels as well as how they interact and influence one another.

There are many areas of psychology that tend to take a more holistic approach to the science of human thought and behavior.

Social psychology, humanistic psychology, and positive psychology, for example, are more focused on understanding how people function on the whole rather than simply looking at a tiny slice of the human experience.

A Word From Verywell

Critics of reductionism often suggest that his approach oversimplifies complex things, but this does not mean that the reductionist approach is not useful. Human behavior is often so varied and complex that breaking certain things down into smaller parts allows researchers a way to understand problems in different ways.

While relying solely on reductionism might lead to gaps in knowledge, using this approach to learn more about some topics can be quite useful and informative. Whether a more reductionist or holistic approach would be the most beneficial way to think about the problem often depends upon the specific topic and situation.

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