Encyclopedia of Animal Cognition and Behavior

Living Edition
| Editors: Jennifer Vonk, Todd Shackelford


  • Swati MishraEmail author
  • Anubhav Pradeep
Living reference work entry
DOI: https://doi.org/10.1007/978-3-319-47829-6_496-1



Parsimony is a principle used as a means of keeping explanations as simple as possible by providing the simplest of explanations to describe an observation or an understanding.


Behavior is the way in which a living organism reacts to a particular situation. In psychology, behavior is thought of as an organism’s external reactions to its environmental stimuli. The analysis of behavior is a science based on the foundations and principles of behaviorism. It can be said that behavior is that particular response of an organism which reflects the kind of stimuli received from the environment. This behavior may be modified by using either positive or negative or manipulating reinforcements from the organism’s environment or according to self-directed intentions or impulses. Human behavior is more complex than animal. Society and culture plays a vital role in shaping human behavior although it is difficult to quantify the extent to which it influences behavior.

Behaviorism is a learning theory that only focuses on objectively observable behaviors and discounts any independent activities of the mind. Behavior theorists define learning as nothing more than the acquisition of new behavior based on environmental conditions (Philips and Soltis 1998). So here, we will discuss the role of the most established principle of parsimony in making conclusion regarding the causes of behavioral and cognitive/learning modifications.

Behaviorists identified conditioning as a universal learning process in different experimental efforts and found two different types of conditioning; each yields a different behavioral pattern. The first one is classical conditioning in which a natural reflex responds to a stimulus. Ivan Pavlov (1890) discovered it during his famous experiment with dogs. Every time Pavlov fed a dog, he rang a bell. Pavlov then rang the bell without feeding the dog, and the dog salivated at the sound of the bell. Pavlov had conditioned the dog to respond to the bell by salivating. Pavlov’s experiment served as the one of the cornerstones of behaviorism (Powell et al. 2001). The other one is behavioral or operant conditioning sometimes also called as instrumental conditioning where a response to a stimulus reinforces or operates through reward for good behavior and punishment for bad behavior.

An eminent behaviorist, B.F. Skinner, in 1977 used reinforcement techniques to teach pigeons to dance and bowl a ball in a mini-alley. Therefore, operant conditioning is a simple feedback system where reinforcement follows the response to a stimulus and then the response becomes more probable in the future (Epstein and Medalie 1983). Thus, behaviorism is based upon the idea that all behaviors are acquired through conditioning, via interaction with the environment. For example, in behavioral psychology, by applying the basic principle of conditioning, people who suffer from psychological disorders are retrained, while cognitive psychology deals with the acquisition, processing, and storing of information in the mind. These mental functions include learning, attention, memory, reasoning, conceptual development, language acquisition, perception, and decision-making.

According to Division 25 of the American Psychological Association, analysis of behavior can be done in three different ways:
  • Firstly, through the experimental investigation of behavior, i.e., by manipulating the environment under control conditions

  • Secondly, through applied behavior analysis (ABA), i.e., by applying the learning behavior principles to real-world situations to change the behavior

  • Finally, through the conceptual analysis of behavior which addresses the philosophical, historical, theoretical, and methodological issues in behavior analysis

All of these three areas of behavioral analysis implicate the fundamental principles, theories, and concepts, which are already well illustrated in the area of animal cognition and behavior. In each area of analysis, to test the economy of explanations involved in the analysis, parsimony plays its pivotal role instantaneously.

What Is Parsimony?

Parsimony is the well-established basic principle in the study of animal behavior, and in science, this principle is applied as discovery tool that guides researcher for the development of scientific models (Epstein 1984). The law of parsimony is introductory to all scientific disciplines and philosophy and in other applications that use logic (Anderson 1978). Parsimony is frequently equated with Occam’s razor, the law which stresses choosing simpler explanations if that simpler explanation fits in totality to the collected data. Therefore, the term parsimonious means the simplest explanation or theory with the least assumptions and variables but with the greatest explanatory power.

Further, the law of parsimony is accepted as an important criterion in science for judging the merits of a theory or an explanation, but it is not the only one. A theory, which is parsimonious, need not be “right” – that is to say, it may not be the most effective or useful description of the body of facts for which it is said to account (Sober and Lewontin 1982).


If one finds that, while exploring the causal factors that generate phenomenon Z, causal factor A accounts for 30% of Z, causal factor B accounts for 50%, and causal factor C accounts for 20%, we can conclude that Z = A + B + C and not worry over additional causal factors so long as the observed evidence is fully accounted for. To elucidate this idea, let’s take one more concrete example. Suppose Meera is trying to understand why her pencil falls to the ground when she lets it go from her hand. After some basic research, she concludes that Newton’s laws of gravity can fully explain this phenomenon of interest. Meera’s friend Danny, however, suggests that while the laws of gravity are responsible for some of the pencil falling to the ground, there also exist millions of invisible leprechauns that catch falling objects and guide them toward the ground. Danny and Meera both provide explanations of the same natural phenomenon, but Danny’s explanation adds unnecessary causal factors. In addition, Danny’s explanation is also very difficult to falsify, even though there is no evidence to support it. One hundred percent of Z can be accounted for by A (gravity), thus adding B (invisible leprechauns) adds nothing to our understanding of why the pencil falls to the ground. Because it adds nothing, parsimony suggests we drop it from our equation (Benjamin 2018).

Hence, parsimony is economy in the use of explanation in conformity with Occam’s razor. Thus, scientifically, parsimony dictates that any example of animal behavior should be interpreted at its simplest and at the most immediate level. It can be done by adding the smallest number of unsupported assumptions, by postulating the existence of the fewest entities and finally by citing the fewest unobservable constructs the simplest explanation

The law of parsimony is also termed as principle of economy or principle of parsimony. The principle of parsimony argues that the simplest of competing explanations is the one that is most likely to be correct. Moreover, this simplest explanation is not considered an undeniable means of deriving the logic or scientific results but affects the importance of simplifying explanations.

The first statement about this principle is credited to a fourteenth-century English scholastic and philosopher William of Ockham. He proposed a rule of logic that is called “Ockham’s razor” (Sober 1994).

By illustrating, an example of pet’s responsive behavior in specific circumstances could be better explained by behaviorists with the principle of parsimony (Thorndike 1911).

For example whenever a person goes out of town leaves her dog, Mason, with a close friend. Mason always defecates overnight in one particular spot in friend’s house. Mason will occasionally do this at her home, but not on a regular basis, and the dog is quite familiar with both friend’s and her home. She could not figure out any possible reason why Mason would be doing this and therefore concluded that it had to be because Mason was mad at her for leaving him. The reason behind this common tendency to jump on anthropomorphic explanations as the most likely reason for a pet’s behavior could be because they believe that these are the simplest explanation for their pets’ behaviors while in the point of behaviorists view it is the most complex one.

What might be some simpler explanations for Mason’s behavior? Mason’s schedule might be different in friend’s home, causing his patterns of elimination to shift. Her friend might not be in the habit of giving Mason a last potty break right before bed, or perhaps Sarah is giving him more treats than he usually gets at home. Mason might be afraid to go outside at friend’s place because of even one experience with a startling noise. Mason might be a bit anxious away from owner, even though Sarah is familiar to him. Perhaps, Mason doesn’t like the texture of what is available for elimination in the yard (Cherry 2018).

Therefore, the principle of parsimony emphasized that the simplest explanations are more straightforward than the other higher thought processes, which could be thought for nastiness to be the motivation for Mason’s defecation.

Debate on nature vs. nurture is one of the oldest philosophical issues within psychology. However, while we discuss about parsimony, nature versus nurture argument empowers the explanation of parsimony principle. The debate starts with certain basic question on behavior like the following: Do genetic or environmental factors have a greater influence on our behavior? Do inherited characters or life experiences play a greater role in shaping our personality?

To get answers to these queries, one must understand the meaning of nature and nurture. Nature refers to all of the genes and hereditary factors, while nurture refers to all the environmental variables including our childhood experiences, how we raised our social relationships, and our surrounding culture. It focuses on the relative contributions of genetic inheritance and environmental factors in human evolution (Breed and Sanchez 2010).

Earlier, a very one-sided approach suggested nature was more important which played pivotal role in the development, while other side suggested that nurture was more significant. Certain philosophers like Plato and Descartes in 2001 suggested that certain things are inborn that they occur naturally regardless of environmental influences, while according to John Locke everything that we are and all of our knowledge are determined by our experience. Theorist John B. Watson in 1915 believed that people could be trained to do and become anything regardless of their genetic background.

An instance of nature versus nurture argument could be that if a man abuses his wife and kids, is it because he was born with violent tendencies or is it something he learned by observing his own parent’s behavior? Another example is that all children are born with an instinctive mental capacity that allows them to learn and produce language but the behavior of a child is influenced by parenting styles and by learning through observation and reinforcement. While considering the views of both sides, the simplest and meaningful explanation of this argument is that genetic factors and environmental factors do play their role together and affect each other in a significant way, and researchers are looking forward for the factors and processes that influence their interactions. The reality is that there is no simple way to unravel the intermingled interactions of genetic factors and environmental factors such as social experiences and overall culture. The genetic factors interact with one another and modulate the influences of environmental factors.

As one school of thought, all differences between men and women are believed to be caused by societal and patriarchal forces. Again, societal influences on behavior are evident, and varying cultural gender labels have had profound and often negative impacts (particularly for women) on individuals throughout history. However, to suggest that all gender differences are the result of societal pressures lacks both parsimony and is factually wrong. What’s more, it offers the potential to be a useless and unproductive interpretation to adopt in many situations. Additionally, for example, the defensive behavior of women avoiding driving in risky areas can be explained by the fact that males of nearly all species are more likely to engage in risky behaviors in all facets of life. There would no need to change what is objectively a very smart and rational behavioral decision. The thought arguing about societal factors that they claim cause gender differences in this specific instance is simply wrong and reflects poorly on the general validity of the feminist movement and the important issues the movement seeks to address. Thus, viewing through the lens of law of parsimony, it must be suggested that the gender-specific protective and defensive behavior of women is the main behavioral cause for this and not any other (Benjamin 2018).

There are occasions where one can predict with confidence that a parsimonious theory is likely to be wrong. For example, Anderson in 1978, a cognitive psychologist, has noted that the most “parsimonious” computer program will probably not be the best one to represent cognition. There is no criterion of parsimony in evolution; redundant and supernumerary organs and mechanisms abound in nature. Further, there is no reason to believe that human cognition – or its counterpart in the real world, the nervous system – has been spared nature’s disinterest.


The principle is itself, ironically, an assertion, one that pervades science but that remains, for the most part, unexamined by scientists themselves. Since it is a criterion by which a theory is judged to be better or worse than another, it may have more value (Walsh 1979).

The principle of parsimony may be nothing more than an instantiation of the principle of “least effort,” and hence we might interpret Mach’s “least possible expenditure of thought” literally (Walsh 1979).

The argument in above examples is about gender differences where parsimony must be considered in the reasoning. It is also suggested that it should not add causal factors that add nothing to explain the phenomena, especially if the behavior can be fully explained in their absence.



  1. Anderson, J. R. (1978). Arguments concerning representations for mental imagery. Psychological Review, 85, 249–277.CrossRefGoogle Scholar
  2. Breed, M., & Sanchez, L. (2010). Both environment and genetic makeup influence behavior. Nature Education Knowledge, 3, 10–68.Google Scholar
  3. Epstein, R. (1984). The principle of parsimony and some applications in psychology. The Journal of Mind and Behavior, 5, 119–130.Google Scholar
  4. Epstein, R., & Medalie, S. M. (1983). The spontaneous use of a tool by a pigeon. Behaviour Analysis Letters, 3, 241–247.Google Scholar
  5. Mach, E. (1960). The science of mechanics: A critical and historical account of its development (6th English ed.). LaSalle: Open Court. (1st English ed., 1893).Google Scholar
  6. Phillips D. C., & Soltis J. F. (1998). Perspectives on learning, Chapter 3. Teachers College Press.Google Scholar
  7. Powell, J., Blakeley, D. W., & Powell, T. (Eds.). (2001). Biographical dictionary of literary influences: The nineteenth century, 1800–1914. Westport: Greenwood Publishing Group. Pavlov, Ivan Petrovich (1849–1936).Google Scholar
  8. Skinner, B. F. (1977). Why I am not a cognitive psychologist. Behaviorism, 5, 1–10.Google Scholar
  9. Sober, E. (1994). Let’s Razor Occam’s Razor. Knowles Dudley (Ed.), Explanation and it’s Limits. Cambridge University Press.Google Scholar
  10. Sober, E., & Lewontin, R. C. (1982). Artifact, cause and genic selection. Philosophy of Science, 49, 159–180.CrossRefGoogle Scholar
  11. Thorndike, E. L. (1911). Animal intelligence. New York: Macmillan.Google Scholar
  12. Walsh, D. (1979). Occam’s razor: A principle of intellectual elegance. American Philosophical Quarterly, 16, 241–244.Google Scholar

Copyright information

© Springer Nature Switzerland AG 2019

Authors and Affiliations

  1. 1.Banaras Hindu universityVaranasiIndia
  2. 2.University of Illinois at ChicagoChicagoUSA

Section editors and affiliations

  • Douglas Sellers
    • 1
  1. 1.Penn State Worthington ScrantonScrantonUSA