Thinking Fast and Slow is about how we think and rationalize the world around us. It touches upon the subtle, and sometimes unnoticed, factors that influence our decision making. It's backed by decades of research by Dr. Kahneman and his close colleague, Amos Tversky. Kahneman uses many interactive examples to illustrate his points to the reader, which I appreciated. They were effective at proving the concepts introduced throughout the book.
Overall, Thinking Fast and Slow was an engaging book that doesn't get too bogged down in details while also being thorough enough to learn new things. Kahneman uses simple metaphors and examples to show how you don't have as much control over your decision-making as you might believe.
I thought about the book even when I wasn't reading it. When I felt strongly about an opinion or a decision I was making, I would reflect on the factors that might be influencing me. This is a sign of a great non-fiction book—in its attempt to explain some aspect of the world, it will actually changes how you perceive the world. Reading books like this add to the context of your lived experience in noticeable ways.
Summary
Very early on, Kahneman introduces the concept of partitions within our brain's structure. It may be more correct to say our mind's structure as the partitions don't have any physical manifestation. It's just a tool to think about the different systems at work within our consciousness. Kahneman claims that these systems have neurophysiological characteristics that we can measure.
Our minds are composed of two major "systems"; Kahneman refers to them as System 1 and System 2. They are engaged in constant dialogue to determine the best system to handle a particular task.
System 1 is primarily in charge of acting as your consciousness, in the sense that as you process your sensual experience, you are processing this stimuli with System 1. System 1 offers up any relevant ideas, memories, or potential actions as this happens. For the most part, our waking hours are primarily occupied by System 1. Most decisions we make and actions we take don't invoke much strain on our mental resources.
It's only when increased focus on a particular task is required do we invoke our mind's System 2, according to Kahneman. System 2 handles anything we would consider "thinking hard", like math problems, memorizing things, trying to speak another language, or even being in an unfamiliar and potentially dangerous situation. What all these tasks and situations have in common is the heightened focus and awareness required for success. We need to invoke System 2 in order to work through things logically, as well as to remember and form new mental patterns.
If our brains were computers, I would liken System 1 to being the cache that stores previous answers to tasks we've seen before. When we encounter a task or situation we've seen before, our pattern-matching brain simply checks for the "answer" it's "computed" before and reuses it.
The reason both our brains and computers have a caching mechanism is because both are lazy and strive to optimize things. Since we repeatedly encounter the same situations every day that require us to carry out some repetitive series of tasks, we naturally form mental automation which allow us to do them without wasting energy. These could be physical tasks, like brushing your teeth, or mental ones like counting change.
A common term for this mental automation is "muscle memory"— but since the brain is not a muscle it's somewhat of a misnomer. This cognitive layer of abstraction is what Kahneman calls System 1. I also believe this is a fundamental component of our sentience. The ability to call these "modules" without worrying about their details allows your brain to conserve its energy for when it needs to focus on something new or important.
Basically, the rest of the book is Kahneman explaining why System 1 can't be trusted a lot of the time and the different factors which can influence System 1's answers without us realizing it.
Highlights
I'm going to share a few quotes I found especially interesting in Thinking Fast and Slow and will briefly comment on them.
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The psychologist Mihaly Csikszentmihalyi (pronounced six-cent-mihaly) has done more than anyone else to study this state of effortless attending, and the name he proposed for it, flow, has become part of the language. People who experience flow describe it as "a state of effortless concentration so deep that they lose their sense of time, of themselves, of their problems," and their descriptions of the joy of that state are so compelling that Csikszentmihalyi has called it an "optimal experience."
— Daniel Kahneman, "Thinking, Fast and Slow" pg. 70
This was a great description for a feeling I've experienced before. When working on a task that balances a difficulty with your existing level of proficiency, you experience "flow" as you work towards its completion. In order for it to be truly fulfilling, it has to be challenging enough to command your full focus, but you also have to be confident in your capability (from past experience and knowledge) to complete it.
I see it as being able to see the rough outline of a solution and the sequence of steps to get there, but without figuring out the details yet. Having this sequence in your mind is what evokes the sense of timelessness as you work because you're only concerned with the completion of each individual step along the path—and have already committed yourself to doing so.
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The only difference between the two groups was that the students conceded that they were influenced by the anchor, while the professionals denied that influence.
— Kahneman, pg. 233
This was in relation to a study conducted on the influence of "anchoring effects" when people are evaluating something's worth. In this example, it was whether a home's asking price was an "anchor value" when trying to determine the value of the home.
Kahneman asked both amateurs and real-estate professionals to conduct the test. The results indicated that for both groups, those who were told the seller's asking price initially were influenced by it. This means that their answers were clustered around the initial value in a statistically significant way. Those who were not told the asking price of the home had more evenly distributed (or distributed around a different value) estimates for the home's value.
This conclusion isn't particularly shocking, but it's a useful effect to know about, especially when conducting negotiations. The more interesting finding is mentioned in the quote: those who are the "experts" at the evaluation are still influenced by the anchor value. It's not a purely objective determination. I think it says something about the nature of professional opinions.
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Resisting this large collection of potential availability biases is possible, but tiresome. You must make the effort to reconsider your impressions and intuitions by asking such questions as, "Is our belief that thefts by teenagers are a major problem due to a few recent instances in our neighborhood?" or "Could it be that I feel no need to get a flu shot because none of my acquaintances got the flu last year?" Maintaining one's vigilance against biases is a chore---but the chance to avoid a costly mistake is sometimes worth the effort.
— Kahneman, pg. 246
Much of the book is devoted to explaining the biases that can affect our judgment. One bias Kahneman highlights is called the availability bias. When evaluating the likelihood of an event occurring, our answer will be influenced by how easily we're able to recall past examples of the event occurring in our lives.
The examples in the quote illustrate this concept well. You will assess the severity of a problem such as neighbourhood crime much higher if your next-door neighbour had their car broken into last week.
Even when provided with facts and statistics, people still err towards their personal experiences and memories when evaluating the likelihood of something. If nothing else, it's important to understand these biases as well as possible, so that you can mitigate their effect on important decisions you have to make.
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This stark version of the problem made Linda famous in some circles, and it earned us years of controversy. About 85% to 90% of undergraduates at several major universities chose the second option, contrary to logic. Remarkably, the sinners seemed to have no shame. When I asked my large undergraduate class in some indignation, "Do you realize that you have violated an elementary logical rule?" someone in the back row shouted, "So what?" and a graduate student who made the same error explained herself by saying, "I thought you just asked for my opinion."
— Kahneman, pg. 294
The Linda problem is quite ingenious, and almost humorous in how it will even trip up people educated in statistics and probability. I think Kahneman meant for this interaction to be viewed as light-hearted humour, but to me it highlights a contradictory perspective of the significance of Kahneman's findings.
Kahneman's entire field of study is based on decision making, which he attempts to describe using Prospect Theory; a theory of human rationality that attempts to predict how humans make decisions in real life. You could argue that trying to prove this theory using controlled studies, which are composed of asking participants hypothetical questions about hypothetical scenarios, is self-contradictory in a sense. Much like how a photon behaves differently when under observation, humans are never completely unaffected by the context with which a question is presented to them.
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homunculus
— Kahneman, pg. 296
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As predicted by denominator neglect, low-probability events are much more heavily weighted when described in terms of relative frequencies (how many) than when stated in more abstract terms of "chances," "risk," or "probability" (how likely). As we have seen, System 1 is much better at dealing with individuals than categories.
— Kahneman, pg. 627
Denominator neglect is a phenomenon where humans will assess low probabilities as being much higher than their true likelihood deserves—especially when the event is a negative outcome! Just by including some low probability outcome in a discussion will inadvertently increase its perceived likelihood by those discussing it and it will be given undue attention.
For example, let's say you're considering corrective laser surgery on your eyes. The opthamologist tells you there's a 1% chance of complications where your eyesight may be impaired. All you'll be able to think about is that improbable event and you will not be comforted much by the 99% chance everything will be fine.
A related discovery was that people seem to be worse with denominator neglect when probabilities are presented to them as relative frequencies i.e. 1 in 1000 cases. Kahneman believes since people are more comfortable when thinking with whole numbers, it's easier to visualize what 1 out of 1000 is. Moreso, it's easier to imagine yourself as being that 1 case out of however many. Just another example of the many idiosyncrasies which make up our reasoning.
Final Thoughts
All in all, I thought this was a fascinating book on a peculiar topic— the mind. Reading and thinking about how we think is a strange experience...it can lead you down some mental rabbit holes. Kahneman did well by unraveling some of these processes that affect our consciousness and presenting them in an understandable way.
Learning how we rationalize and make decisions is a valuable endeavor. Anyone that seeks a deeper understanding of themselves will gain something from this book. Removing internal biases allows you to see the world, and your place within it, more clearly. I was definitely more engaged and in tune with my thoughts and feelings while reading this book; I hope to remember some of the lessons and insights and carry them forward in life. Can't ask for much more in a book.