Rationality Test

Assess your critical thinking and identify your cognitive biases

20-90 minutes
Detailed feedback
Scientifically validated
Completely freeOpen sourceAnonymousIn the public interest

What is rationality?

Rationality is the ability to form beliefs that accurately reflect reality (epistemic rationality) and make decisions that maximize your goals (instrumental rationality).

While intelligence (IQ) measures cognitive capacity, rationality measures how effectively you use that capacity. Whether rational thinking can be lastingly improved remains scientifically debated, although some targeted interventions show short-term effects.

This test evaluates several key dimensions of rational thinking: probabilistic reasoning, scientific reasoning, resistance to cognitive biases, and the ability to update your beliefs in light of new evidence.

What this test measures

Scientific Foundations

This test is inspired by the CART (Comprehensive Assessment of Rational Thinking) developed by Professors Keith E. Stanovich, Richard F. West, and Maggie E. Toplak, published by MIT Press in 2016.

CART is based on over 40 years of research in cognitive psychology on biases and heuristics, notably the pioneering work of Daniel Kahneman (2002 Nobel Prize in Economics) and Amos Tversky.

Key References:

  • Stanovich, K. E. (2009). What Intelligence Tests Miss: The Psychology of Rational Thought. Yale University Press.
  • Stanovich, K. E., West, R. F., & Toplak, M. E. (2016). The Rationality Quotient: Toward a Test of Rational Thinking. MIT Press.
  • Kahneman, D. (2011). Thinking, Fast and Slow. Farrar, Straus and Giroux.
  • Frederick, S. (2005). Cognitive Reflection and Decision Making. Journal of Economic Perspectives, 19(4), 25-42.

Note: This test is a free educational adaptation. It uses public domain questions and original variants inspired by scientific literature.

Choose your version

Express Version

~20 min

6 essential modules

  • Quick overview of your biases
  • Personalized feedback
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RECOMMENDED

Full Version

~90 min

17 in-depth modules

  • Comprehensive assessment
  • Detailed analysis + charts
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💡 Tip: Choose a quiet time when you are well-rested

This test is a free and open-source project :)

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Rationality Test | CART Adapted