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Thinking, Fast and Slow Summary

About Thinking, Fast and Slow Book

Major New York Times bestseller
Winner of the National Academy of Sciences Best Book Award in 2012
Selected by the New York Times Book Review as one of the ten best books of 2011
A Globe and Mail Best Books of the Year 2011 Title
One of The Economist's 2011 Books of the Year
One of The Wall Street Journal's Best Nonfiction Books of the Year 2011
2013 Presidential Medal of Freedom Recipient
Kahneman's work with Amos Tversky is the subject of Michael Lewis's The Undoing Project: A Friendship That Changed Our Minds

In his mega bestseller, Thinking, Fast and Slow, Daniel Kahneman, the renowned psychologist and winner of the Nobel Prize in Economics, takes us on a groundbreaking tour of the mind and explains the two systems that drive the way we think.

System 1 is fast, intuitive, and emotional; System 2 is slower, more deliberative, and more logical. The impact of overconfidence on corporate strategies, the difficulties of predicting what will make us happy in the future, the profound effect of cognitive biases on everything from playing the stock market to planning our next vacation—each of these can be understood only by knowing how the two systems shape our judgments and decisions.

Engaging the reader in a lively conversation about how we think, Kahneman reveals where we can and cannot trust our intuitions and how we can tap into the benefits of slow thinking. He offers practical and enlightening insights into how choices are made in both our business and our personal lives—and how we can use different techniques to guard against the mental glitches that often get us into trouble. Winner of the National Academy of Sciences Best Book Award and the Los Angeles Times Book Prize and selected by The New York Times Book Review as one of the ten best books of 2011, Thinking, Fast and Slow is destined to be a classic.

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Thinking, Fast and Slow by Daniel Kahneman
How Humans Think

How Humans Think

"Thinking, Fast and Slow" is an extensive introduction to the biases and inner mechanisms of the human brain.

While primarily a behavioral economics book, you will also find out about your limitations, how to more efficiently convince people, and understand why people make certain decisions despite feeling they are irrational.

All the conclusions are validated through experiments that Kahneman performed along the years.


Two Systems

Two Systems

The human brain is controlled by two separate systems:

  • System 1 - Very fast, it works on intuition and evolves as we encounter common situations;
  • System 2 - Slower. We tend to avoid using it too much, but it is mandatory for complex problems that can't be answered by System 1, such as math problems.

You are not aware of which system is controlling the brain unless you make a conscious effort.

The following few ideas rely on this dual system distinction.


Priming and Anchoring

Priming and Anchoring

An answer to a number question can be influenced by previous information (even if it is completely unrelated to it). Using this strategy to influence decisions is called priming.

It acts as an anchoring effect, the human starts from the real answer he/she would give and goes up/down towards the number that was proposed (accidentally or not). This anchoring can be more or less strong (e.g. when the actual answer is 10, the suggested one is 5, and the person answers 8, it had a 20% impact).



“Nothing in life is as important as you think it is, while you are thinking about it”



Understanding 2 Systems

Understanding 2 Systems

System 1 comprises the oldest parts of the brain. It operates automatically and involuntarily. This system is always functioning and is responsible for most of the day-to-day activities. It is also responsible for our reactions to danger, novelty, and intuition.

System 2 allocates attention and completes tasks that require effort. System 2 is a newly evolved part of the brain, and only humans have a highly developed prefrontal cortex.


Bat and Ball Problem

Bat and Ball Problem

Try to solve this problem -

"A bat and a ball cost $1.10 in total. The bat costs $1.00 more than the ball. How much does the ball cost?"
If you say $1 for the bat and 10 cent for the ball, then it's wrong because you just used the system - 1.
(Answer is given in the last idea of the article.)


System One and System Two

Our brains have two "systems" that complement eachother, with their own capabilities, limitations and functions.

  • System One is fast, automated and precise, but can be easily tricked and has a small working window.
  • System Two is slower, can make complex thoughts achieved in a specific algorithm and takes control over it's brother when he needs to with it's long but limited attention buffer.


System One

With it's lighting fast reactions, System One is present in almost every common situation. It's actions are sometimes unstoppable and can be trained to steal tasks from the second System.

Depending on the complexity, here are some tasks that System One makes:

  • Solves simple math like 2+2
  • Recognizes a good chess move (if you are a chess expert)
  • Reads words on big ads
  • Drives the car on a empty road
  • Makes you look in the direction of a sound


System Two

Being slower but very powerful, this part of the brain can partialy suppes the other one while taking control on our body and forming logical and complex operations that need an attention span while being easily interrupted, like:

  • Solves complex math like 412* 525
  • Searching for a person
  • Controlling your behaviour
  • Completing a formular
  • Parking a car


"'Thinking, Fast and Slow' by Daniel Kahneman is a profound exploration of the human mind, unraveling the intricacies of how we think, decide, and often misjudge.

True Nature Of Decision Making

True Nature Of Decision Making

We all believe that we are in control of most things around us, or at least that's what we aim to believe, thrive to imply and fear any opposing statements, but what if you come to understand that you are not in control as you ought to be, not only with your surrounding, but with your very own mind.

Dr. Danial Kahneman addresses the idea of how our minds work and whethere if it is biased in his book "Thinking fast and slow" which we will be exploring together in the next few ideas, whether you decide to continue reading or not, it's up to you ..... Isn't it?


What's Fast And What's Slow?

What's Fast And What's Slow?

So you might be thinking, I am in control, i mostly can swear that i direct my own mind to focus on certain things which are interesting to me, and hence i design my own perspective about things, i hold the brush and paint this painting, well i hate to tell you that that is what Kahneman called the systems 1 and 2

System 1: This is fast, intuitive, and automatic thinking. It's the kind of thinking we use for quick, everyday decisions and reactions.

System 2: This is slower, more deliberate, and analytical thinking. It's used for more complex cognitive tasks that require effort and concentratio n


Your In Control Of System 2

Your In Control Of System 2

In order to understand what is it you are in control of (System 2) we have to address system 1 first, of course both of the previously mentioned are a sort of explatory names to demonstrate the two styles of thinking our brains do, and they are non existent in real science.

So system 1 is the main decision maker in your head, it's your arms turning the driving wheel whenever your eyes see the desired U-turn, it's what comes to your head when you see the equation 2 + 2 =? it's simply the shortcuts your brain has devoloped throughout the years and does it automatically making you not in control



A reliable way to make people believe in falsehoods is frequent repetition, because familiarity is not easily distinguished from truth. Authoritarian institutions and marketers have always known this fact.




Nothing in life is as important as you think it is, while you are thinking about it




Our comforting conviction that the world makes sense rests on a secure foundation: our almost unlimited ability to ignore our ignorance.



Main cause of biased judgment

Main cause of biased judgment

Your mind likes the feeling of coherence and sentiment of habit, of déjà-vu. 

From an evolutionnary point of view, Sapiens needs to have a construction of reality clear. 

  • Do you have to treat with this plant ? No, you recognize those red berries that causes flu.

D. Kahnemann calls this process the System 1. This is a cognitive agent which is trying to explain all of you hear, see and feel by a causal link.

A first way to improve your critical mind is to admit that chance, at least multiple causes make events happen. 

  • Explain that WW2 is caused by the madness of Hitler is simple, not accurate.


Loss aversion : Why you're not already rich

Loss aversion : Why you're not already rich

Lucky you are, you can make a wonderful bet. At equal propabilities :

  • 50% : You receive 120 $
  • 50% : You lose 100 $

Stop reading, would you accept this ?


If you're like the majority of us, you refused this gamble.

Our brain is not familiar with statistics. You don't think to the utility of the bet, you see two situations :

  1. You change your current situation. You win a little quantity of money, cool. OR you lose almost the same amount, you swear against yourself, what an idiot decision
  2. You don't change your situation, nothing happens

This is the loss aversion, our brain tends to avoid losses.


Confirmation bias : How powerful are conspiracy-theories

Confirmation bias : How powerful are conspiracy-theories

Good stories are simple. 

And when they seem coherent, we accept them without activating our critical mind (see "Main cause of biased judgment" in this collection). 

In particular, the conspiracy theories have another viral weapon. As the elements which take part of the theory are batching and seem plausible, you tend to strenghten your thoughts without taking into account what is belying them. This is the confirmation bias.

As you're sure that D Trump is fighting the "deep state", he accuses the media to spread fake news. Bim 'n boom ! You begin to believe that Thanos manage TV and papers.


Learn how our cognitive systems drive our behaviours and help with decision making. Discover the system 1 and system 2 thinking and how unconscious biases leads to building our beliefs about the world.


We can't live in a state of perpetual doubt, so we make up the best story possible and we live as if the story were true.



Who Is Daniel Kahneman

Who Is Daniel Kahneman

Daniel Kahneman was a Nobel Prize winning psychologist, economist and an author of best-selling books such as “Thinking Fast & Slow”. Also, Daniel Kahneman was a professor of psychology at Princeton University. He is also someone who took pleasure in admitting his mistakes and working towards improving his beliefs.


Two Systems Of Thinking Govern Our Behaviour

Two Systems Of Thinking Govern Our Behaviour

Do you know that even the single stream of thoughts we usually have is governed by two parallel cognitive systems which Daniel Kahneman calls System 1 and System 2.


The Characters Of The Story

The Characters Of The Story

There are two types of thinking, one is fast and the other is slow. Each type of thinking is its own system with individual abilities, limitations, and functions. The main difference between the two is that fast thinking requires little to no effort to operate, whereas a conscious effort is necessary for slow thinking to work. For example, you would use fast thinking to solve the problem “2 + 2 = ?” and slow thinking to fill out a tax form.


<p>This distinction becomes ve...

This distinction becomes very important when we realize that attention is not unlimited, and when you go beyond the budget you have, you will fail. This is why you can only do multiple things at once when they are relatively easy and undemanding tasks, such as speaking to a passenger while driving on an empty road. However, you would not attempt to have a conversation while making a turn onto a busy road as you need to focus your attention on driving.


<p>While your two types of thi...

While your two types of thinking often split the labor between themselves well, they can clash when an automatic reaction (fast thinking) comes into conflict with an intention to control it (slow thinking). A universal example of this is trying not to stare at an oddly dressed couple in the same room as you. Sometimes, these clashes are caused by cognitive illusions. An example is experiencing a strong attraction towards someone with a history that forms a negative pattern. The good news is, these illusions can be overcome.


Here are 3 good lessons to know what’s going on up there:

  1. Your behavior is determined by 2 systems in your mind – one conscious and the other automatic.


System 1 is automatic and impulsive.

It’s the system you use when someone sketchy enters the train and you instinctively turn towards the door and what makes you eat the entire bag of chips in front of the TV when you just wanted to have a small bowl.


System 2 is very conscious, aware and considerate.

It helps you exert self-control and deliberately focus your attention. This system is at work when you’re meeting a friend and trying to spot them in a huge crowd of people, as it helps you recall how they look and filter out all these other people.


Two Sides Of Mind.

There are two different systems of thinking. Fast responsive and slow one, which we are considering as our true-self.

  • Both systems are working unstoppable, regardless of our will.
  • Fast system is first in line to take action and it's completely out of our control.
  • Second system is being involved when we need to process more complicated tasks.


First Glance

First Glance

You don't need to think deeply to understand emotion of women on picture above. One glance is enough to predict next actions. Fast thinking did the work out of your will.

23 * 76 = ?

You don't have the same ability to solve the followed equation. Though your brain automatically launch second system to work.


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