What Is the Principle of Parsimony in Psychology?

Karen Doll, Author
Updated on April 11, 2024

The law of parsimony, a problem-solving principle, states that the simplest explanation for something is typically the most likely. Putting this into practice requires focusing on the most impactful and effective evidence and data, without considering extraneous factors.

parsimony psychology

When discussed in the context of psychology, parsimony refers to seeking explanations and theories that are practical, with clear conclusions, to address mental health issues. The approach can be very helpful, as often, people who seek out psychological help find the unnecessary complexity in breaking down their underlying issues overwhelming. For clinicians and researchers, parsimony can be used to narrow down the most likely causes and factors between variables they are trying to understand.

Defining Parsimony

The term “parsimony” was derived from the Latin word parser, meaning to be sparing. The general meaning of the word is excessive thriftiness or frugality. In some contexts, this has a negative connotation, suggesting a lack of generosity or miserliness. However, there is also value in the concept of parsimony. Parsimony in psychology entails identifying the simplest and most accurate explanation for brain processes and human behaviors

The law of parsimony suggests identifying the simplest, least complicated explanation of a situation or observation. Even philosopher Aristotle supported this method, saying “The more limited, if accurate, is always preferable.”

The law of parsimony is often referred to as Occam’s razor. It was named after theologian William of Ockham in the 1300s, who authored the term “numquam ponenda est pluralitas sine necessitate.” This means “Plurality must never be posited without necessity.”

Years later, scientist Sir William Hamilton named the phrase “Occam’s razor” to describe the process of “shaving away” unnecessary or peripheral assumptions in logical reasoning. Subsequently, scientists in varying fields adopted this practice in their studies. It involves using the fewest steps, with minimal resources, leading to the optimal conclusion.

Benefits of Applying Parsimony in Psychology

Brain function is complex and much of it remains a mystery. While scientists are committed to simplifying the study of psychology and human behavior, there is still a gap in understanding. Parsimony can make psychology less abstract and more tangible. A good therapist or mental health professional can use this framework to provide accurate and valid explanations that are relatable and easy to understand.

Parsimony psychology ensures that explanations are simple and helpful, and do not rely on unsupported assumptions. It also relies on tangible observations and proven data with replicable results. Parsimonious descriptions may include physical objectives, activities, facial expressions, or test results.

Parsimony is not about taking the fastest route. Rather, it’s about finding the most efficient, comprehensive, and effective path possible. If there is a simpler yet equally thorough solution, this is the desired choice. This simplicity also makes communication easier, therefore increasing the chances that concepts are understood. 

In the spirit of parsimony, let’s break it down. Parsimony is all about:

  1. Using the fewest assumptions.
  2. Choosing the simplest explanation that fits the evidence.

What the Critics Say

Sounds simple enough, right? It may sound straightforward, but it requires discipline to apply effectively. Unfortunately, it’s easy for psychologists to overcomplicate things. Critics worry that there is a broad gray area in the process of parsimony psychology, and this can make it difficult to explain complicated behaviors and cognitive processes.

Final Thoughts

In trying to understand a problem experts can often have a bias toward the more interesting, complicated, or familiar explanations. While they may be correct, it’s wise to begin by considering the simplest possible solution and testing that first. If the most obvious answers prove to be incorrect, it then makes sense for the explanations to increase in complexity as the straightforward ones are dismissed.


Karen Doll, Author

Karen Doll has been a Licensed Psychologist in the Twin Cities for 20 years, working in organizational consulting. She leverages her education in Clinical Psychology with her leadership assessment expertise in her practice. She is an executive coach focusing on helping people maximize their potential.

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