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Are We Rational Animals?

Are We Rational Animals?Aristotle held the belief that man is a rational animal. A growing body of research suggests otherwise.

Rational: of or based on reasoning (from Webster’s New World Dictionary).  This ambiguous definition is similar to what is given by many people when asked to define rational.  This type of definition is virtually worthless as it becomes open to a plethora of interpretations.  In order to teach and express the importance of rational thinking it is imperative to precisely define the concept.

What is rationality?

Rationality is concerned with two key things: what is true and what to do (Manktelow, 2004).  In order for our beliefs to be rational they must be in agreement with evidence.  In order for our actions to be rational they must be conducive to obtaining our goals.

Cognitive scientists generally identify two types of rationality: instrumental and epistemic (Stanovich, 2009). Instrumental rationality can be defined as adopting appropriate goals, and behaving in a manner that optimizes one’s ability to achieve goals. Epistemic rationality can be defined as holding beliefs that are commensurate with available evidence. This type of rationality is concerned with how well our beliefs map onto the structure of the world.   Epistemic rationality is sometimes called evidential rationality or theoretical rationality. Instrumental and epistemic rationality are related.  In order to optimize rationality one needs adequate knowledge in the domains of logic, scientific thinking, and probabilistic thinking.   A wide variety of cognitive skills fall within these broad domains of knowledge.

Characteristics of rational thought

  • Adaptive behavioral acts
  • Judicious decision-making
  • Efficient behavioral regulation
  • Realistic goal prioritization
  • Proper belief formation
  • Reflectivity

(Characteristics taken from Stanovich, 2009, p.15)

Irrationality and intelligence

Why do we act and behave irrationally?

There are two issues that contribute to our irrational behavior — a processing problem and a content problem. The processing problem refers to how our brain processes new, incoming information. When choosing what strategies to apply when solving a problem, we generally choose the fast, computationally inexpensive strategy — the one that takes our brain less energy to figure out.

Although we have strategies that have great power, they are more computationally expensive, are slower, and require more concentration than the faster cognitively thrifty strategies. Humans naturally default to the processing mechanisms that require less effort, even if they are less accurate. Individuals with high IQs are no less likely to be cognitive misers than those with lower IQs.

A second source of irrational thinkingthe content problem — can occur when we lack specific knowledge to think and behave rationally. David Perkins, a Harvard cognitive scientist, refers to “mindware” as rules, strategies, and other cognitive tools that must be retrieved from memory to think rationally (Perkins, 1995; Stanovich, 2009). Think of “mindware” as a human being’s software — the programming that makes our brains run.

The absence of knowledge in areas important to rational thought creates a mindware gap. These important areas are not adequately assessed by typical intelligence tests. Mindware necessary for rational thinking is often missing from the formal education curriculum. It is not unusual for individuals to graduate from college with minimal knowledge in areas that are crucial for the development of rational thinking. Another type of content problem, mindware contamination, occurs when one has acquired mindware that thwarts our goals and causes irrational action.

There have been a variety of tests developed to assess rational thinking skills. Utilizing tests of rationality are just as important as using intelligence tests. Rational thinking skills can be learned, and with the development of rational thinking skills we can expect better judgment and decision making in everyday life.

Irrational thinking has a big impact in our lives. Because of irrational thinking “physicians choose less effective medical treatments; people fail to accurately assess risks in their environment; information is misused in legal proceedings;” (Stanovich, 2009), millions of dollars are spent on useless programs, services and products in government and private industry; millions and millions of dollars are spent on dietary supplements; and the list goes on.

Stay tuned for part two, in which I’ll discuss intelligence as a predictor of rationality and implications for research.


Manktelow, K. I. (2004). Reasoning and rationality: The pure and the practical. In K. I. Manktelow & M. C. Chung (Eds.), Psychology of reasoning: Theoretical and historical perspectives (pp. 157-177). Hove, England: Psychology Press.

Perkins, D. (1995). Outsmarting IQ: The emerging science of learnable intelligence. New York: Free Press.

Stanovich, K. E. (2009). What intelligence tests miss: The psychology of rational thought. New Haven, CT: Yale University Press.

Photo by Yuri Samoilov, available under a Creative Commons attribution license.

Are We Rational Animals?

Jamie Hale, M.S.

Jamie Hale, MS., is a researcher specializing in eating behavior, cognitive science (various aspects) and scientific reasoning. Jamie has written seven books and co-authored one. He is a member of the World Martial Arts Hall of Fame (recognition of my strength and conditioning work with martial artists), college instructor, learning / memory consultant and board member of Kentucky Council Against Health Fraud.

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APA Reference
Hale, J. (2016). Are We Rational Animals?. Psych Central. Retrieved on May 27, 2018, from https://psychcentral.com/blog/are-we-rational-animals/


Scientifically Reviewed
Last updated: 14 Jun 2016
Last reviewed: By John M. Grohol, Psy.D. on 14 Jun 2016
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