THINKING FAST and SLOW-Daniel Kahneman |Book Summary

In my quest to learn more about how my mind works, I came across this amazing book called “Thinking Fast and Slow” written by Daniel Kahneman, a world-renowned psychologist and Nobel Prize winner in Economics.

The author Daniel Kahneman teaches us how two different systems in our brain are constantly fighting with one another to take the control of our behavior, decisions, and actions.

Learning valuable lessons from “Thinking Fast and Slow” can assist us in comprehending what is actually going on within our minds.

Major takeaways from “Thinking Fast and Slow” are as follows-

1- Fast brain and slow brain

thinking fast and slow book summary
  • Our brain works with two systems: Intuition and Slow thinking.
  • Method 1 is an intution-based ‘automatic’ system that may be summed up as quick thinking.
    • System 1 is quick.
    • It works automatically, unconsciouly and involuntarily.
    • We use it readily and instinctively in everyday decisions, like as driving, remembering our age, or interpreting someone’s facial expression.
  • System 2 is a effortful system — a slow-thinking system that requires us to exert effort and some time in order to arrive at an answer.
    • It is only used when it is absolutely required to reason, compute, analyse, and solve issues.
    • It verifies or corrects System 1 judgement and is more trustworthy.
    • It requires time, effort, and attention.
    • It assists you in exercising self-control and carefully focusing your attention. This technique comes into play when you’re trying to solve some complex problems.

2- Fight among two systems

thinking fast and slow book summary
  • While both the two systems appear to be well-designed for coping with the world, they actually cause significant issues.
  • The reason for this is that system 1 takes over when system 2 is more suited.— or we can say, many a times our quick intuition can lead us to the wrong answers and the wrong conclusions.
  • The system two is basically designed to keep monitoring the thoughts and actions that system one creates.
  • When system 1 encounters a difficult problem that it is unable to handle, it will activate system 2 to figure out the specifics.
  • However, your brain occasionally considers things to be easier than they are. System 1 believes it can manage it, despite the fact that it cannot, and you make a mistake as a result.

3- Your brain is a lazy fellow

thinking fast and slow book summary
  • According to the law of least effort, your brain utilises the least amount of energy possible for each activity.
  • This is because your brain hates spending energy or making efforts. It wants to be in the comfort zone and feel relaxed all the time.
  • It likes things that are familiar and simple to understand. It is always longing for things that make it feel like it’s in a safe environment.
  • Because slow thinking takes deliberate effort, System 2 is most effective when we have self-control, attention, and focus.
  • When we don’t have self-control, such as when we’re fatigued or worried, System 1 takes over impulsively, thus clouds our judgement.

4-Confirmation bias

thinking fast and slow book summary
  • A right decision is based upon considering many aspects, but we often focus on the one factor that gives us the most pleasure, which can prove to be a major error.
  • This is because accourding to the law of least effort our mind always wants to be in comfort zone.
  • Thats why one somebody gives you an easy suggestion or solution (no matter how vague it is) for your problem, you just accept it right away.
  • The availability of easy solution accourding to your desire immediately confirms you to not think deeply.
  • While making any sort of decisions you should take different aspects in consideration. This can only happen when you work with system two- think slow and attentively.


This is a great read for anyone who is interested in understanding psychology and the procedure of thoughts.

If you’re having trouble slowing down and making judgments, “Thinking Fast and Slow” can be a good read to investigate and comprehend your thought processes in order to better.

The conclusion is that you should consider the broad picture and ensure that you are drawn to a commitment for a variety of reasons that you understand.