57 pages • 1 hour read
Thinking, Fast and Slow
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Themes
Human Judgment Is Often Unconscious and Irrational
The idea that human judgment is rarely conscious or rational is central to the book and the hook on which Kahneman hangs the entire work. He establishes this purpose in the Introduction, where he explains that “[we] believe [we] know what goes on in [our] mind, which often consists of one conscious thought leading in an orderly way to another. But that is not the only way the mind works, nor indeed is that the typical way” (3). In short, Kahneman asserts that people generally do not understand how their minds work. This book is his effort to educate readers about the workings of the human mind, beginning with the systems of judgment that inform decision-making.
According to Kahneman, the mind has two systems of judgment. System 1 is fast-thinking and intuitive, while the slow-thinking System 2 is more rational and deliberative. The intuitive nature of System 1 leads to errors of judgment, resulting in unconscious, irrational decisions. There are several factors that contribute to this. For example, System 1’s quest for causal explanation means it tends to perceive the world at face value, a phenomenon Kahneman calls “what you see is all there is,” or WYSIATI. Its reliance on past experience and associations also leads to inaccurate judgments and poor decisions. While System 2 is triggered in situations that require careful evaluation or deliberation, this system requires significantly more energy and concentration. Thus, the mind defaults to System 1, even though it is susceptible to bias, ignorance, associative reasoning, and other shortcomings.
Because the mind prefers cognitive ease, System 1 is the dominant process through which we make decisions. Absent an unexpected anomaly that it cannot resolve, System 1 will generally run the brain on auto-pilot. This status quo suits System 2 because it seeks to avoid committing effort to action. Thus, while System 2 has the potential to correct many common mistakes, it is unlikely to do so without a catalyst.
Psychology Can Improve Decision-Making and Well-Being
Kahneman believes that an understanding of human psychology can improve individual well-being. By clarifying how the mind works, he aims to improve the reader’s understanding of human decision-making, empowering them to make more rational decisions to achieve better outcomes and improved quality of life. That mission is reflected in the book’s very structure, as it is organized to educate readers about the two systems of judgment, demonstrate how those systems affect behavior, examine other factors that influence judgment, and consider how this knowledge can improve our decisions in the future.
Kahneman cites several examples to support his argument, including his work with Amos Tversky in developing prospect theory, which supplanted the erroneous assumptions about economic decision-making that prevailed prior to the 1970s. Economists had long adhered to theories of rationality that envisioned humans as wholly rational and selfish economic actors. However, these “Econs” were unlike the humans that psychologists know because humans “have a System 1. Their view of the world is limited by information that is available at a given moment […] and therefore they cannot be as logical and consistent as Econs” (269). By accounting for humanity’s irrational, intuitive tendencies, prospect theory laid the foundation for modern behavioral economics.
Another example is the Apgar test, which shows how an understanding of the tendencies of the human mind can improve outcomes on the individual level. The test, which uses variables and scores to assess the health of newborn infants, created a formulaic standard that was much more consistent and accurate than assessments based on intuition or expertise. The test is credited with reducing infant mortality and is still used today.
Ultimately, Kahneman hopes that the vocabulary and framework detailed in this book will “bring together in memory everything we know about a bias, its causes, its effects, and what can be done about it” (418), so that we can make better decisions and thus improve our well-being and quality of life.
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