books, Psychology

The Two Modes of Thinking

In his book, ‘Thinking, Fast and Slow’, on judgement and decision making, Daniel Kanheman starts off by describing the setting in which the readers of his book could benefit the most: the proverbial watercooler, a proxy for social settings where gossip can flourish. Unlike most serious books, which often require you to disconnect from people so that you can focus on the material, he says the following:

“Why be concerned with gossip? Because it is much easier, as well as far more enjoyable, to identify and label the mistakes of others than to recognize our own. Questioning what we believe and want is difficult at the best of times, and especially difficult when we most need to do it, but we can benefit from the informed opinion of others.”

It is indeed an arduous task to debug your own thinking and thus this book, that deals entirely with systematic errors in thinking, called biases, can be difficult to come to terms with. Therefore, Kanheman proposing that we start learning by pointing out the mistakes of others is an ingenious move on his part.

“So this is my aim for watercooler conversations: improve the ability to identify and understand the errors of judgement and choice, in others and eventually in ourselves, by providing a richer and more precise language to discuss them. In at least some cases, an accurate diagnosis may suggest an intervention to limit the damage that bad judgments and choices often cause.”

The two characters of this book, called System 1 and System 2 represent the two modes of thinking, Fast and Slow respectively. They are tools that we’ll employ to understand how our cognitive machinery works.

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.

If you wish to see these at work consider look at the following examples:


The capital of India

Orange man with small hands

To most people, all these sentences will conjure up answers almost immediately:

4, New Delhi and Trump.

Observe that you did not have to think too much about it.

Now consider the following examples:

24 x 13


Checking the validity of a logical argument such as

Premise 1: A car will not run without gas.

Premise 2: I don’t have any gas in my car.

Conclusion: My car will not run.

Although trivial, these exercises required a finite amount of your attention to be completed.

Essentially, this is the difference between the two modes of thinking, Fast and Slow, respectively. One is intuitive, automatic, always working and the other slow, deliberate and called to action when the first one doesn’t have an answer. System 2 requires effortful thinking.

I’ll use an example that Kanheman uses to illustrate the autonomy of System 1 and the differences between the characters of our story.

Look at this figure:

What do you observe?

If you’re like most people, you will see that the line at the top is longer than the one at the bottom. But by now you must’ve realized that the twist here is that both lines are equal in length. This simple illusion gives you a lot of information about how these systems work. System 1 is always on and “feels” that the line on top is longer. Despite your system 2 having having formed the belief that the lines are equally long based on the information that I gave you, you will continue to see the first one as longer because System 1 cannot be forced to stop making intuitive judgments and give you quick answers, which as we will see later can be wrong sometimes.

“To resist the illusion, there is only one thing you can do: you must learn to mistrust your impressions of length of lines when fins are attached to them.”

If you observe your day-to-day decision making, you will see the interplay between these two systems, whether it is having an extra piece of cake when you’re tempted or choosing sleep over exercise. In both cases, System 1 will make a split second decision for you, but if you have a strong System 2 you will stop yourself and reconsider that initial impulse.

Why use System 1 and System 2 to explain thinking?

Kanheman uses these because they serve as useful functions. It should be noted that they have no particular residence in the brain, they are just proxies. It makes for compelling storytelling and greater retention of concepts.

“You have been invited to think of the two systems as agents within the mind with their individual personalities, abilities, and limitations.”

This book is one of my favorites and a real eye opener. Happy reading!

As always, comment/criticisms are appreciated.!


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