Cognitive Limits: Thinking, Fast and Slow May 11 2020, 0 Comments

Do we want our students to adopt the reasoning that scientists do? Well, of course we do.

The first thing to recognize about rational thinking is that is not “natural,” except in its most primitive forms. Rational thinking is highly cultural. In order for a human being to become a reasoning being, the act of reasoning must be learned, and sustained, in a way that is similar to the way one learns a language. We acquire language (and reasoning) by imitating our competent speakers and thinkers among our family and community. We become competent at language (and reasoning) by practicing, thousands of times, in everyday situations. And we become expert at language (and reasoning) by studying them explicitly.

Science, of course, is a discipline which requires a capacity to reason effectively. So… if a young person is attempting to learn science, that person must simultaneously learn how to reason.

But this brings us to a very important educational problem. Children do not find reasoning easy to do, or easy to learn. This difficulty is dissected  in Daniel Kahneman’s book “Thinking, Fast And Slow”. Kahneman points out that we possess two quite distinct modes of thinking: Rational thinking, and intuitive thinking. They are quite different, as summarized in the table below.

Intuitive Thinking

Rational Thinking



Easy – little energy required; faint evidence of raised glucose / oxygen consumption

Difficult – takes a lot of biological energy, high glucose / oxygen consumption

Occurs almost without effort

Requires intense effort to push to a conclusion

Pleasant – ends with very positive feelings

Unpleasant – evokes strong feelings of stress

Positive facial expressions: raised eyebrows, relaxed smile, open eyes

Negative facial expressions: forehead frown, downturned mouth, squinted eyes

May be impacted by senses, but proceeds to conclusion without registering a disturbance.

Easily distracted by senses. People close eyes, seek quiet place, still their bodies, etc.

Quite convincing to thinker. Feels “right.” Seldom followed by spontaneous resort to rational confirmation or disconfirmation.

Not always convincing to thinker. Often followed by appeal to intuitive thinking to confirm or disconfirm rational conclusion

Brain activity is global, includes more frontal cortex, less language, motor planning centers

Prominent brain activity in language centers, motor planning centers in brain

Associative reasoning: Given an input, neurons seek associated memories, feelings, instances, etc. and aggregate them toward a largely confirmatory conclusion.

Differential reasoning: comparing parallel situations, comparing statements with recalled facts, limited number of operations, looks for nature of differences, etc.


From Kahneman, “Thinking, Fast and Slow”



  1. What are the takeaway points here?

First – One goal of science instruction is student competency in the second kind of reasoning - rational thinking. And adolescent human brains can be expected to avoid rational thinking, thus making student competency a very challenging task. Any curriculum that teachers create must directly address this difficulty.

Second – Intuitive thinking interferes with rational thinking. Faced with a lab setup or a textbook problem, a student is more likely to grasp for meaning using intuition, than to force his brain into rational mode. Intuitive thinking can easily disrupt the student’s effort at rational reasoning. Any curriculum that we design must directly address this likelihood.

Third – Science is a physical. It deals with real things in the real world. Students’ intuitive thinking about the real world takes place in the same mental space that governs their own physical movement in the real world. This mental space is called the “body-schema” by a number of researchers. Based upon my own observations, I believe that high school students use a small number of predictive / explanatory schematic strategies to guide their intuitive thinking as they attempt to make sense of an unfamiliar physical situation. When we plan science curriculum, we must anticipate that students will use “body-schematic strategies” to make sense of our instructions.

The IntuitivScience curriculum materials are designed with these three things in mind. Follow along. I will develop these ideas in future blogs.