It's difficult to know where to start with this book. Khaneman is an extremely accomplished and knowledgable economist, and this book span a ton of a content and subject matters. I think the best way to describe this book is "Daniel Kahneman attempts to sum up a significant portion of the knowledge has gained over his career as a Nobel prize winning economist, and makes them readily accessible to people who have no reference point on the subject matter." That was quite a mouthful, but it's the only way I can think to describe it; there's just so much subject matter.
Thinking Fast and Slow definitely made me think a lot about the ways that I think and process information, and I would recommend it to just about anyone. This book exposes a lot of interesting ways that people think, and how those processes lead to flaws and incorrect conclusions in a lot of situations. That's one of the best parts about this book: by seeing all the incorrect ways that the brain comes to conclusions, I feel I have a better chance of recognizing those patterns and trying to rectify it.
One of the big takeaways for me was when Khaneman delves into causal vs. statistical thinking. He makes the argument that people are generally bad at statistical thinking, and usually think about facts and events in terms of causes and effects. He illustrates this with an example; suppose I told you that women of above average intelligence tend to date men who are less intelligent than them. You could probably produce a couple reasons as to why that might be true, and it is probably your natural inclination to do so. However, it's not particularly necessary. This can be answered with simple statistics; a woman of above average intelligence is in the 60-70th percentile, which would make her also more intelligent than 60-70% of men. In fact, if intelligence is a normal distribution then it would increase this number to about 80%. So the dating pool for a woman of above average intelligence includes 60-80% of individuals less intelligent than her. There doesn't need to be any causes and effects to explain this one, however that is how our brains are want to think.
However, people will think statistically about the above question if asked to before hand, and can often come to the correct result when instructed to. This is important to note because it's another key part of the book: What you see is all there is. Basically, people will only act upon patterns of thinking and data points when instructed, and will rarely think about different ways to approach a problem. If I ask you to think of some reasons as to why highly intelligent women date less intelligent men, the odds are that you are going to do just that without even considering the statistical model. People only act upon what is offered to them right there, they rarely consider anything outside of the immediate in front of them.
Another great takeaway was the portion on primers. Primers are things that you think about before executing a task, and what you are primed with before doing something has an effect on how well you perform. Money is on example of a primer. Individuals who were asked to consider money and finances 5-10 minutes before performing basic tasks were found to be more analytical and better at objective judgements. However, they were also more likely to describe their personal lives as more lonely and express more solitary behavioral patterns. Khaneman ties this in with studies on recency, or seeing how your current mood affects your view of your life overall. Whatever is happening in your immediate surroundings indeed has an effect on how you describe your whole life; people who had a negative experience 10 minutes prior to being asked to rate their life reported a notable decrease in their overall life satisfaction, but noted drastically improved scores immediately afterwards when asked to list out all the positive things that have happened to them in the last week.
There was also a great section on how your brain "load balances". Basically, your brain has a hard time answering nuanced, difficult questions. However, it does a great job of substituting in easier to answer questions instead of answering the hard ones, to make our decisions a lot quicker and remove a lot of thinking requirement. This often leads to incorrect answers that are poorly though out. The best example is the question, "Are you an above average driver?". About 70% of people say they are an above average driver, but there is no way that is true. The truth is your brain doesn't answer the posed question. To actually consider whether you are above average takes a lot of variable measurement. You have to think about all other drivers, how many accidents they get in, how often they run red lights, merge on top of others, etc. There are many things that can constitute poor driving, so instead of think about all that most peoples brains will simply substitute in a much easier question to answer: "Are you a good driver?". In many ways it is similar, however it is much easier to answer. "Are you a good driver?" requires significantly less cognitive overhead, so our brains choose to answer that instead.
I mean, a lot of this does feel a bit obvious when you type it all out and read it in this condensed format. However, I think that the true benefit of this book is making the reader aware of these patterns of thought. Yea, having a bad day can effect your entire outlook on life in that moment, but that is a bit of an erroneous way to think. You should be able to look past the current mood you are in an assess the facts. The whole point of the book is to let the reader see that there are patterns of thinking that affect everyone, and to see that those patterns can often lead to incorrect judgements. Once we are aware of those fallible ways of thinking, then we can adjust our thinking to more accurate models with better results. We can't do that until we are aware though!
There's a ton more that I didn't touch on in this post that I liked and did not like. I think Khaneman discounts managers and CEO's a bit too much when talking about business success and focuses too much on luck. However, I had a ton of great take aways from this book, and if you found any of the stuff in this post interesting then I definitely recommend you read it!