Why Your Judgment Sucks // Summary of Daniel Kahneman’s Thinking, Fast and Slow (2011)

Israeli-American psychologist Daniel Kahneman’s bestselling Thinking, Fast and Slow (2011) describes the finer points of decision-making. It’s an engaging showcase of the innate biases of the mind and unthinking approaches to decision-making.

Human Beings are Intuitive Thinkers

Kahneman is a behavioral economics pioneer and the winner of the 2002 Nobel Memorial Prize in Economic Sciences. His lifelong collaboration with Amos Tversky (1937–96) has molded humans’ thinking about human error, risk, judgment, decision-making, happiness, and more. Tversky died in 1996, so he did not share in the Nobel.

Thinking, Fast and Slow explores what Kahneman calls the “mind’s machinery” as two coexisting modes of thought (“fast and slow,” as the title says.) Kahneman splits the brain into two radically divergent ways, employing a two-tier model of cognition.

• System One makes judgments instantly, intuitively, and automatically, as when a cricket batsman decides whether to cut or pull. A significant part of System One is “evolved heuristics” that lets us read a person’s expression in a microsecond from a block away, for example. And it can’t be switched off. System One’s thinking is fast and effortless. It often jumps to the wrong conclusions, relies on hunches and biases, and perhaps overconfident.
• System Two is slower, conscious, calculated, and deliberate, like long division. Its operations require attention. System Two is what we think of as “thinking”—slow, tiring, and essential. It’s what makes us human. Even if System Two believes it is on top of things, System One makes many of our decisions.

System One Isn’t All Flawed

In a world that often necessitates swift judgment and rapid decision-making (e.g., fight or flight,) a person who solely relies on deliberative thinking (System Two) wouldn’t last long. Doctors and firefighters, for example, through training and repetition, develop what’s called “expert intuition” that helps them identify patterns and impulsively devise the right response to a complex emergency.

We as humans are not simple rational agents. Consequently, our thinking boils down to two “Systems” of thinking/processing. As we strive to make better decisions in our work and personal lives, it benefits us to slow down and use a more deliberate System 2 way of thinking. Learn to doubt your fast/quick way of thinking!

Human Intuition is Imperfect

Thinking, Fast and Slow is an eye-opener in various ways. It can be a frightening catalog of the biases, shortcuts, and cognitive illusions that come to err our judgment—the endowment effect, priming, halo effect, anchoring effect, conjugation fallacy, the narrative fallacy, and the rest. Such mental processes are not intrinsically flawed; they are heuristics—rules of thumb, stereotypes, shortcuts. They are strategies the mind embraces to find a path in a tsunami of data.

Kahneman teaches how to recognize situations that require slower, deliberative thinking. Kahneman asserts that the value of the book is to give people the vocabulary to spot biases and to criticize the decisions of others: “Ultimately, a richer language is essential to the skill of constructive criticism.”

Recommendation: Read Daniel Kahneman’s Thinking, Fast and Slow (2011.) As one of the most popular non-fiction books in the last decade, it’ll open your eyes to the quirky and error-prone ways in which you can be influenced in ways you don’t suspect.

The conceptions behind behavioral economics make Thinking, Fast and Slow a laborious read. Many chapters are bogged down by hair-splitting details of his rigorous scientific work and academic gobbledygook. It’s a commanding survey of this field, but it’s superbly written and intelligible to non-experts.

Complement with Rolf Dobelli’s accessible The Art of Thinking Clearly (2013.)