Thinking, Fast and Slow

by Daniel Kahneman

In the first phase, a tentative plan comes to mind by an automatic function of ass...

The next phase is a deliberate process in which the plan is mentally simulated to check if it will w...

Herbert Simon, perhaps the only scholar who is recognized and admired as a hero and founding figure by all the competing clans and tribes in the study of decision making.

but it will make more sense when I repeat it now: “The situation has provided a cue; this cue has given the expert access to information stored in memory, and the information provides the answer. Intuition is nothing more and nothing less than recognition.”

If you want to be an expert at something knowing information , formulas , algorithms arent enough. You need to keep repeating and experiencing all available scenarios so that your brain stores those moments and ties the relative solutions to those moments. So that when a familiar situation accurs the solution is recognized.

The moral of Simon’s remark is that the mystery of knowing without knowing is not a distinctive feature of intuition; it is the norm of mental life.

How does the information that supports intuition get “stored in memory”?

We have inherited from our ancestors a great facility to learn when to be afraid.

All of us tense up when we approach a spot in which an unpleasant event occurred, even when there is no reason to expect it to happen again.

On many occasions, however, you may feel uneasy in a particular place or when someone uses a particular turn of phrase without having a conscious memory of the triggering event. In hindsight, you will label that unease an intuition if it is followed by a bad experience.

What Pavlov’s dogs learned can be described as a learned hope. Learned fears are even more easily acquired.

Fear can also be learned—quite easily, in fact—by words rather than by experience.

Emotional learning may be quick, but what we consider as “expertise” usually takes a long time to develop.

The acquisition of expertise in complex tasks such as high-level chess, professional basketball, or firefighting is intricate and slow because expertise in a domain is not a single skill but rather a large collection of miniskills.

Learning high-level chess can be compared to learning to read. A first grader works hard at recognizing individual letters and assembling them into syllables and words, but a good adult reader perceives entire clauses.

An expert reader has also acquired the ability to assemble familiar elements in a new pattern and can quickly “recognize” and correctly pronounce a word that she has never seen before.

In chess, recurrent patterns of interacting pieces play the role of letters, and a chess position ...

After thousands of hours of practice, however, chess masters are able to read a chess situation at a glance. The few moves that come to their mind are almost always strong and sometimes creative. They can deal with a “word” they have never encountered, and they can find a new way to interpret a familiar one.

Klein and I quickly found that we agreed both on the nature of intuitive skill and on how it is acquired.

When can you trust a self-confident professional who claims to have an intuition?

Klein had spent much time with fireground commanders, clinical nurses, and other professionals who have real expertise.

I had spent more time thinking about clinicians, stock pickers, and political scientists trying to make unsupportable long-term forecasts.

his d...

attitude was trust and respect; mine w...

He was more willing to trust experts who claim an intuition because, as he told me, true experts know ...

I argued that there are many pseudo-experts who have no idea that they do not know what they are doing (the illusion of validity), and that as a general proposition subjective confid...

We are confident when the story we tell ourselves comes easily to mind, with no contradiction and no competing scenario.

Klein and I eventually agreed on an important principle: the confidence that people have in their intuitions is not a reliable guide to their validity.

If subjective confidence is not to be trusted, how can we evaluate the probable validity of an intuitive judgment? When do judgments reflect true expertise? When do they display an illusion of validity? The answer comes from the two basic conditions for acquiring a skill:

an environment that is sufficiently regular to be predictable an opportunity to learn these regularities through prolonged practice

When both these conditions are satisfied, intuitions are li...

The accurate intuitions that Gary Klein has described are due to highly valid cues that the expert’s System 1 has learned to use, even if System 2 has not learned to name them.

stock pickers and political scientists who make long-term forecasts operate in a zero-validity environment. Their failures reflect the basic unpredictability of the events that they try to forecast.

Some environments are worse than irregular. Robin Hogarth described “wicked” environments, in which professionals are likely to lea...

Lewis Thomas the example of a physician in the early twentieth century who often had intuitions about patients who were about to develop typhoid. Unfortunately, he tested his hunch by palpating the patient’s tongue, without washing his hands between patients. When patient after patient became ill, the physician developed a sense of clinical infallibil...

An extreme failure of this kind is unlikely because human learning is normally efficient. If a strong predictive cue exists, human observers will find it, given a decent opportunity to do so.

Statistical algorithms greatly outdo humans in noisy environments for two reasons: they are more likely than human judges to detect weakly valid cues and much more likely to maintain a modest level of accuracy by using such cues consistently.

It is wrong to blame anyone for failing to forecast accurately in an...

Claims for correct intuitions in an unpredictable situation are self-delusional at best, sometimes worse. In the absence of valid cues, intuitive “hits” are due either to luck or to lies.

Remember this rule: intuition cannot be trusted in the absence of stable regularities in the environment.

Expertise is not a single skill; it is a collection of skills, and the same professional may be highly expert in some of the tasks in her domain while remaining a novice in others.

Surgeons can be much more proficient in some operations than in others.

Among medical specialties, anesthesiologists benefit from good feedback, because the effects of their actions are likely to be quickly evident.

In contrast, radiologists obtain little information about the accuracy of the diagnoses they make and about the pathologies they fail to detect.

Anesthesiologists are therefore in a better position to develop useful intuitive skills. If an anesthesiologist says, “I have a feeling something is wrong,” everyone in the ope...

Similarly, a financial expert may have skills in many aspects of his trade but not in picking stocks, and an expert in the Middle East knows many things but not the future.

The unrecognized limits of professional skill help explain why experts are often overconfident.

conclusion was that for the most part it is possible to distinguish intuitions that are likely to be valid from those that are likely to be bogus.

If the environment is sufficiently regular and if the judge has had a chance to learn its regularities, the associative machinery will recognize situations and generate quick and accurate predictions and decisions. You can trust someone’s intuitions if these conditions are met.

Unfortunately, associative memory also generates subjectively compelling intuitions that are false. Anyone who has watched the chess progress of a talented youngster knows well that skill does not become perfect all at once, and that on the way to near perfection some mistakes are made with great confidence.

In a less regular, or low-validity, environment, the heuristics of judgment are invoked. System 1 is often able to produce quick answers to difficult questions by substitution, creating coherence where there is none.