“Confidence is a feeling, which reflects the coherence of the information and the cognitive ease of processing it.”

What does it mean?

Confidence is not a quiet calculation of how likely you are to be right. It is a feeling, fed by how well the information hangs together and how easily it is processed. The usual reading connects the sentence to WYSIATI: a coherent fragment feels certain. A competing reading still treats a confident expert as someone who has seen more, which is sometimes true and not what the feeling measures. The sentence is chapter 20. Cognitive ease is the fluency of the thought. Fluency is not a census of the evidence.

Did Daniel Kahneman really say this?

The library’s label is Well attested. His English. Page 212 of the 2011 Farrar, Straus and Giroux edition, in the chapter on the illusion of validity. He adds that declarations of high confidence tell you a coherent story has been built, not that the story is true.

Where it comes from

Thinking, Fast and Slow (2011), chapter 20, The Illusion of Validity, p. 212

Approximate date: 2011.

How to use it

A consultant in a London trust who answers at once, and sounds sure, has given you the feeling he describes. Ask what would have made the story harder to process. Difficulty is not proof. Ease is not proof either, which is the sentence.

A mindset reading

Take admitted uncertainty more seriously than a smooth declaration, which is his own advice in the same passage. Do not hear that as a ban on being sure when the evidence is actually full.

Understand the philosophy

Chapter 20 is 'The Illusion of Validity'. The key claim is that confidence is a feeling. Chapter 7 supplies the story that feels easy. The library's entry on overconfidence is the bias this sentence is naming, and the profile links it. The planning fallacy is the same family of optimism, applied to a timetable.

Related

• “System 1 operates automatically and quickly, with little or no effort and no sense of voluntary control. System 2 allocates attention to the effortful mental activities that demand it, including complex computations.”

  Well attested

• “I will use a cumbersome abbreviation for it: WYSIATI, which stands for what you see is all there is.”

  Well attested

• “It is the consistency of the information that matters for a good story, not its completeness. Indeed, you will often find that knowing little makes it easier to fit everything you know into a coherent pattern.”

  Well attested

Related bias. Availability bias. Availability bias judges how common something is by how easily examples come to mind. Vivid, recent, or personal cases feel frequent. A dull record of ordinary cases is harder to recall and gets underweighted.

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