Thinking, Fast and Slow

This is an invaluable book that every person who considers him/herself educated should read - even study. Indeed, it is a scandal that mastering the material in this book isn't considered an essential component of a high school education. The author was awarded the Nobel in Economics for his work on what he calls decision theory, or the study of the actual workings of the typical human mind in the evaluation of choices, and the book itself presents the findings of many decades of psychological studies that expose the endemic fallacious thinking that we are all prone to, more or less. The lives of all of us could be improved by lessons learned from this book, not just individually, through self-education, but also on the large scale, if the large scale decision makers in this society in and out of government could be educated as well. In fact, it is largely because these large scale decision makers are no better than the rest of us in their ability to think straight and plan well, that society is as screwed up as it is, and that essentially all of its institutions are diseased and corrupt. The lesson there, however, is that decision making needs to be returned to the individual - that the powers that be need to be deprived of their powers to mess up the lives of the rest of us. Despite the many virtues of this book - it is well-written, engaging, and its academic author reasonably restrained in the tendencies of his tribe to blathering in abstractions - it is a bit disappointing at the very end, when the author proves unable to synthesize all his material into a comprehensive theory of the thinking, and deciding mind - or at least into a set of carefully formulated principles that provide a succinct summary of the principles of human thinking, both typical and ideal. Kahneman uses throughout a construct that implies that we are of two minds: System 1 is the fast-thinking, intuitive, mind, prone to jumping to conclusions; while System 2 is the slow-thinking analytical mind, that is brought into play, if at all, only to critique and validate the conclusions that we have jumped to. System 2, we are told, is lazy, and if often just rubber-stamps the snap judgements of System 1, or if pressed, rationalize them, instead of digging critically as well as constructively into the complex underpinnings of the material and sorting them out as best it can. Instead of working this construct up into a comprehensive model of mind, K merely uses it as a loose schema for representing the kinds of thinking thought to underlie the results derived from the many psychological experiments that he here reports on. This neglect raises the question at many points as to just how well the experimenters have really understood the thinking that underlies the behavior of their subjects. But this, I am sorry to say, is a weakness of virtually all psychological experimentation, which is still just beginning to come to grips with the complexity and varieties of cognitive style of the human mind. What Kahneman does do, however, is to provide convenient labels for many characteristic types of fallacious thinking, although again, the exact role of System 1 and System 2, and their interaction, is inadequately explicated. Instead, towards the end of the book, another, somehow related, but nominally independent theme is developed: the disturbing divergence between the experiencing self and the remembering self. This is in itself such an interesting and important idea, so pregnant with both psychological and philosophical implications, that it could have used a fuller treatment, and again, there is no coherent integration of this theme with the System1/System2 construct. The idea here is that our present experience includes our most salient memories of previous experiences - for example the highlights of past vacations, or out of the ordinary episodes of our lives. Somewhat surprisingly, though, what we remember is a systematic distortion of the actual experience. Our memory collapse the duration of various aspects of our experience and highlights only the peak moment(s) and the final moments, perhaps with a nod toward the initial presentation of the experience. And this systematic distortion of the actual experience in all its fullness, can lead us to make irrational and detrimental choices in deciding whether to repeat the experience in the future. Thus, a bad ending to an otherwise wonderful experience can spoil the whole thing for us in memory, and cause us to avoid similar experiences in the future, even though by simply anticipating and improving the ending we might make the whole experience as wonderful as most of the original was. Likewise, subjects in experiments involving either long durations of pain, or much shorter episodes of pain with a higher peak, were consistently more averse to the latter rather than the former - or they overemphasized the way these presentations ended as a factor in judging them as a whole. These are important findings that go the heart of the question of how best to steer our course through life, but here is the only attempt at integration of this remembering vs experiencing self theme, and the System 1/ System 2 theme that I find in the final chapter, Conclusions: "The remembering self is a construction of System 2. However, the distinctive features of the way it evaluates episodes and lives are characteristics of our memory. Duration neglect and the peak-end rule originate in System 1 and do not necessarily conform to the values of System 2". There is more here, but it merely repeats the earlier analysis of the relevant experiments. No evidence is presented as to the respective roles of System 1 and System 2 with respect to the laying down of memory, to its decay, or with respect to a recently discovered phenomenon: memory reconsolidation. Nor is any account taken of what has been learned, much of it in recent decades, about the interactions between short, intermediate, and long term memory, or any of the radically different modalities of episodic (picture strip) and semantic (organized, abstracted) memory. Consequently, Kahneman's vague reference to the "characteristics of our memory" is essentially a ducking of the question of what the remembering self is. I think that at best, the finding of the replacement of the original experience by an abstract predicated on peak-end bias is an exaggeration, though there's no question that "duration neglect" is in operation, and a good thing too, unless K means by "duration neglect" not just the stretches of minimally changing experience (which have little memorial significance anyway, but even the consciousness of how long the edited out parts were (this distinction was never made in Chapter 35, where the theme of the remembering vs. the experiencing self is first taken up). Speaking for myself anyway, I have a much fuller memory of my most important experiences than Kahneman seems to indicate. Naturally the highlights are featured, but what I tend to remember are representative moments that I took conscious note of at the time, as though making a psychological photograph. I remember these moments also because I bring them up from time to time when I'm thinking about that experience. For example, I'm thinking now of a long distance race I did in 2014 (a very tough half-marathon, with almost 2000' of climbing). I remember: the beginning section as well as the ending section; each of the rest stations; certain moments of each of the major hill climbs; at least one moment from each of the descents; and a number of other happenings during the almost three hour event. For me in this race, the peak experience occurred right at the end, when I all but collapsed, yet managed to stagger to the finish line. That ending does naturally come first to mind as a representation of the entire event, but it is merely the culmination of a long and memorable experience with many moving parts, and if I want, my remembering self can still conjure up many other moments, as well as a clear sense of the duration of each of the sections of the course. Over many years most memories fade, and it's certainly reasonable to suppose that in extreme cases, where they are all but forgotten, only a single representative moment might be retained. However, if we can say anything for sure about memory it is this: we remember what we continue to think of and to use, and we do that precisely because this material has continuing importance to us. The recent research in memory reconsolidation tells us that when we do bring up memories only occasionally, we reinforce them, but we also edit and modify them to reflect our current perspectives, and sometimes we conflate them with other seemingly related knowledge that we've accrued. We are thus prone to distort our own original memories over time, in some cases significantly, but we may still retain much more of the original experience that just the peak and the end, and if we do reinterpret our memories in the light of more recent experience, that's not necessarily a bad thing. In any case, the memories that occur in the present may be said to be a joint project of the experiencing as well as the remembering self, which rather erodes the whole Two Selves concept that Kahneman first posited. I do not mean to criticize the valuable evidential material in the book, and in general I think that Kahneman, and the other researchers and thinkers whom he quotes, have drawn reasonable conclusions from the experiments they report on. But ultimately, the book, as well as the fields both of psychology and brain neurophysiology suffer both in coherence and meaningfulness because they aren't predicated on a more comprehensive theory of mind. It's the old story in science, first formulated by Karl Popper in his 1935 book, The Logic of Scientific Discovery: unless we approach the data with an hypothesis in mind - unless, indeed, we seek out data likely to be relevant to a particular hypothesis, we're not going to make any enduring progress in understanding that data in a comprehensively meaningful way, let alone be able to make falsifiable deductions about elements of the system for which we have at present no data. Popper's quotation from the German philosopher Novalis comes to mind - "Theories are nets: only he who casts will catch." In the final, "Conclusions", chapter, K caricatures the abstract economists' model of homo econimicus (man as a rational optimizer of his utility), contrasting it with the more sophisticated and experientially grounded model of psychologists such as himself. In keeping with his penchant for framing (or spinning) his presentation favorably to his own perspective, he calls the economists' model "Econ", and his own "Human". In fact, "Econ" was never meant to represent man in all his humanity, and Kahneman's Economics Nobel, recognizing his decision theory contributions to economics, was preceded by many other Nobels to economists who had been expanding the concept of the economic actor into psychological territory for decades. In fact, the essential view of the Austrian economists dating from the 1920s (von Mises, Hayek, and their predecessors) is that economics is in the end wholly dependent on psychology because it is predicated on the unknowable, unquantifiable subjective value preferences of humans, acting individually and in concert. Cautious generalizations can perhaps be made about human psychology in general, but I think that on the whole the Austrians have been a bit wiser in their restraint than Kahneman and his many, and mostly lesser, pop psychology compatriots have proved in their often sensationalist extrapolations from lab experiments. Here is an example, I think of Kahneman over-reaching. He speaks repeatedly of the laziness of System 2, and its foot dragging reluctance to get involved in the thinking process, but in the real world, snap judgements are good enough for immediate purposes, and the better part of rationality may be to go with one's fast thinking intuitive System 1: indeed, Kahneman acknowledges this himself in passing, both in his beginning and his ending, but this isn't enough to counterbalance the overall argument of his book. Kahneman also, in his final chapter, speculatively extends his findings into the political sphere (his liberal Democratic Party bias has already been made clear by gratuitous and somewhat annoying usage of salient modern politicians in examples), but not to any great effect. Kahneman advocates "libertarian paternalism" consisting of government programs that people are enrolled in automatically unless they opt out by checking a box on forms - thus manipulating the presentation frame so as to trick them into signing on to what some government bureaucrat thinks is good for them. Of course, as long as people are allowed to opt out, one can't call the choice here anything but libertarian, though to be consistent with their socialist mores, liberals like Kahneman really ought to object to such practices as being manipulative advertising. This libertarian finds nothing objectionable about the way such a choice might be presented - after all, the average man, if adequately educated and prepared for the real world, should have no trouble seeing through the frames. What is not only paternalistic, but totalitarian in spirit, is the extortion of taxpayer money to finance such government programs in the first place. Somehow, it fails to occur to Kahneman that most people could be trained to recognize and avoid fallacious thinking during all those years of enforced and mostly wasteful schooling - just as most people can be trained to recognize the Müller-Lyer illusion for what it is. IMO every high school graduate should be required to learn to recognize and avoid the paradigm cases of fallacious thinking presented in Thinking, Fast, and Slow, and this material could profitably be expanded to cover the many rhetorical tricks used by the manipulators and spinmeisters, both public and private, who batten off of our society. With such training in critical thinking, and with the reintroduction of enough honest and rigor to begin high school graduates up to the 12th grade reading and writing proficiencies that were routine in the 1950s, the need for college as life preparation would be altogether obviated, and most young people could avoid wasting their early years in college, piling up debt, and get on with their work and/or their self-education, as they chose.

As some background, I am 68 yrs old and have a semester and a HALF of college! I often say this in group meetings and just to sound super smart. I am not sure exactly why I ordered this book - maybe it was the purdy pencil on the front or the desire to find some fast answers to my questions! When it arrived I thought what have I done? Where are the pictures and quick statements for motivational purposes? Why are there so many word and SO small? Why is this book so THICK? I started reading it JUST so my GFF would think "wow, where did his coloring books go" and found I could NOT put it down. I have often sought answers as to WHY I do what I do and feel like I do. I have wonderful therapists and doctors over the years that have told me I have mild depression and a drinking problem. I have good meds and follow their guidance but still wanted to know more! I am not saying Mr. Daniel Kahneman is my new therapist or should replace my current one, I am simply suggesting that the insights and research have provided such deep and wonderful NEW thoughts and actions for me - and in just the first chapters. I have begun smiling all the time and doing math in my head as often as possible - even on walks or strolls! O sure, I will return to my coloring books, but it is wonderful to find research that provides answers to questions I didn't know I had and those I thought I could ever find answers. But I believe I have found a marvelous resource in this book and Daniel Kahneman. Who knows, maybe I'll get that other half of a semester in the months ahead!

I did not consider this book for its contentious ideas regarding human thought, but rather as an interesting framework regarding thought processes and a different perspective on the way we process information. I find Daniel Kahneman's "Thinking Fast and Slow" is a fantastic read as an expansion of his earlier work with Amos Tversky on the human decision-making pathways of heuristics and algorithms which the book are presented as the two "main characters" as he likes to call them: System 1 (the fast) and System 2 (the slow). Overall, I enjoyed Kahneman's engaging use of examples and simple "mini-experiments" which allowed me to try and witness the results firsthand. The addition of light humor in his simple, yet robust writing style keeps the didactic tone at the forefront of the text while still keeping the admittedly long book interesting enough to keep the pages turning. Many of the points that the author brings up throughout the book are usually preceded or supported by some sort of "do-it-yourself" type exercises. One of my favorite examples is the "add-1" and "add-3" exercises where you make strings of 4 digit numbers. You read a number, wait 2 seconds, then say a new number with each of the digits incremented by either 1 or 3. For example, the number 1234 in the add-1 exercise would become 2345 and in the add-3 scenario, it would become 4567. These exercises are used to indicate just how what the extent of working memory is in most people and the physiological strain that effortful processing can have on both the body and the mind. One of the most interesting devices I found in the book was the dichotomy Kahneman creates from the moment I turned to the first page. He tells the reader to treat the book as two major characters. The first character is the unsung "hero" of the story of our mind: System 1. It is always on and gets its hand first on anything and everything our mind comes into contact with. The main principles or System 1 is that it is quick, more "emotional", and more susceptible to biases and errors. It operates efficiently, with little effort, and is constantly operating in the background. In other words, System 1 operates in what Kahneman and Tversky call "heuristics." On the other hand, Kahneman brings in a supporting character that believes it is the main character: System 2. System 2 is more deliberate and conscious, and is what we identify with when we refer to ourselves. However, it requires much more conscious effort and thus is only used when System 1 cannot come to some sort of solution, answer, or analysis with the information at hand. Thus, System 2 operates via algorithms and is less prone to emotional and cognitive errors, though not entirely immune. This underlying dichotomy thematically arises in our everyday lives and in a multitude of different cognitive tasks. Kahneman touches on topics including psychology, neuroscience, and his Nobel Prize winning specialty: economics. Personally, as a debater, I have a special interest in economic theory as arguments involving economic considerations are a common occurrence in rounds. This is probably why Kahneman's discussion of these systems contextualized in an economic scenario particularly caught my eye. In the aforementioned circumstance, he brings up the psychological notion of prospect theory, which earned him his Nobel Prize in the field of (behavioral) economics. To begin with the, prospect theory accounts for the error in the expected utility hypothesis which states that people make decisions, such as gambling, based on the expected payout. However, using Kahneman's terminology, this would be more of System 2 centric approach. In experimentation, he reveals that decision making involving risk factors is more heuristical in nature and is therefore governed predominantly by System 1 wiring. Prospect Theory suggests that decision making is based off the potential total loss or the potential total gain instead of the expected outcome (based of the equation x = Σxnpn). This also indicates that people tend to be more "risk-aversive" by nature. In other words, humans tend to fear loss more than they hope for gain. Additionally, a loss of a certain magnitude will yield in more negative emotions than a gain of equal amount would elicit positive emotions. While the economic and behavioral applications of decision making is interesting to me, other readers might find some of the other ideas in the wide variety of topics that Kahneman delves into more engaging or meaningful. There are five overarching parts that he outlines in his book. In the first part of the book, Kahneman focuses on setting up the dichotomy of the two systems and the experimental basis for their existence. In part two, he indicates the impact of system 1 in heuristical analysis. Specifically, he discusses the cognitive biases that come from the quick pathway of thinking. This section is particularly important in making the point that there lies some counterbalance between the speed of processing and the accuracy that lies therein. Part three discusses the implications that people are overconfident in their decision-making. Though decisions based off of gut instincts may "feel" right, they may be proven to be considered mathematically irrational. There is also the underlying notion that compared to careful statistical analysis, we are more often wrong in our perceptions than we are truly accurate. The penultimate part refers to the role of decision-making criterion in the choices that people make. Risk analysis is the largest factor in understanding how and why people consistently choose certain courses of actions over others. The main takeaway is the belief that people are inherently risk aversive. This is beneficial both evolutionarily, but also in the sense that is logistically makes sense in most scenarios to err towards a false negative (Type II statistical error) than it is to a false positive (Type 1 statistical error). Finally, Kahneman comes full circle to holistically comparing the two systems and how they interact with each other in order to assist us in solving the problems that come to us day to day. In the end, I feel that this book has given me great insight into not only how we think, but also why we think that way. I feel more aware of cognitive biases as well as potential errors in my judgment and reasoning that I know I not only have made in the past, but will probably involuntarily continue to do so in the future. Overall, I believe there is much to take away from this book both on a conceptual and a lifestyle level. It is important to realize that one of the biggest ways to develop as a person is to understand our respective selves and this book, to a large extent, has helped me further that understanding.

Back in 1994, Massimo Piattelli-Palmarini, Director of the Institute of San Raffaele in Milan, Italy, wrote a charming little book about common cognitive distortions called Inevitable Illusions. It is probably the very first comprehensive summary of behavioral economics intended for general audience. In it, he predicted that the two psychologists behind behavioral economics - Amos Tversky and Daniel Kahneman - would win the Nobel prize. I didn't disagree with the sentiment, but wondered how in the world were they going to get it since these two were psychologists and there is no Nobel prize in psychology. I didn't think there was much chance of them winning the Nobel Prize in economics. I was wrong and Piattelli-Palmarini was right. Kahneman won the Nobel prize in Economic Sciences. (Tversky unfortunately prematurely passed away by this time.) Just as Steve Jobs who was not in the music industry revolutionized it, the non-economists Kahneman and Tversky have revolutionized economic thinking. I have known Kahneman's work for quite some time and was quite excited to see that he was coming out with a non-technical version of his research. My expectations for the book were high and I wasn't disappointed. Since other reviewers have given an excellent summary of the book, I will be brief in my summary but review the book more broadly. The basis thesis of the book is simple. In judging the world around us, we use two mental systems: Fast and Slow. The Fast system (System 1) is mostly unconscious and makes snap judgments based on our past experiences and emotions. When we use this system we are as likely to be wrong as right. The Slow system (System 2) is rational, conscious and slow. They work together to provide us a view of the world around us. So what's the problem? They are incompatible, that's what. System 1 is fast, but easily swayed by emotions and can be as easily be wrong as be right. You buy more cans of soup when the display says "Limit 12 per customer". We are on autopilot with this system. System 1 controls an amazing array of behavior. System 2 is conscious, rational and careful but painfully slow. It's distracted and hard to engage. These two systems together provide a backdrop for our cognitive biases and achievements. This very well written book will enlighten and entertain the reader, especially if the reader is not exposed to the full range of research relating to behavioral economics. This book serves an antidote to Malcolm Gladwell's Blink. Although Gladwell never says that snap judgments are infallible and cannot badly mislead us, many readers got a different message. As the Royal Statistical Society's Significance magazine put it "Although Gladwell's chronicle of cognition shows how quick thinking can lead us both astray and aright, for many readers Blink has become a hymn to the hunch." While Kahneman does show how "fast thinking" can lead to sound judgments, he also notes how they can lead us astray. This point is made much more clearly and deliberately in Kahneman's book All my admiration for the brilliance and creativity of Kahneman (and Tversky) does not mean that I accept 100% of their thesis. Consider this oft-quoted study. Linda is 31 years old, single, outspoken, and very bright. As a student, she was deeply concerned with the issues of discrimination and social justice, and she also participated in anti-nuclear demonstrations. Which is more probable? 1. Linda is a bank teller. 2. Linda is a bank teller and is active in the feminist movement. Eighty-five percent of test subjects chose the second option, that Linda was a bank teller and active in the feminist movement. Kahneman's interpretation is that this opinion is wrong because the probability of a (random) woman being a bank teller is greater that than person's being a bank teller AND a feminist. What Kahneman overlooks here is that what most people answered may not be the question that was asked. The respondents may not have been concerned with mathematical probabilities, but rather could be responding to the question in reverse: Is it more likely for a current activist to have been an activist in the past compared to others in the profession? A more formal and theoretically better argued rebuttal of some of Kahneman's hypotheses can be found in the works of Gerd Gigerenzer. Kahneman notes that even top performers in business and sports tend to revert to the mean in the long run. As a result, he attributes success largely to luck. I'm not so convinced of this. There can be alternative explanations. People who achieve high degree of success are also exposed to a high degree of failure and the reversion to the mean may be attributable to this possible mirror effect. Spectacular success may go with spectacular failure and run-of-the-mill success may go with run-of-the-mill failure. Eventually everyone may revert the mean, but the ride can be very different. Chance may not account for that. Another concern is that much of the work is done in artificial settings (read college students). While much of what we learnt can perhaps be extended to the real world, it is doubtful every generalization will work in practice. Some may find Kahneman's endorsement of "libertarian paternelism," not acceptable. More importantly, when applied to the real world it did not always found to work. In spite to these comments this book is written carefully in a rather humble tone. I also appreciated Kahneman's generous and unreserved acknowledgement of Tversky's contributions and his conviction that, had he been alive, Tversky would have been the co-recipient of the Nobel Prize. My cautionary comments probably have more to do with the distortions that might arise by those who uncritically generalize the findings to contexts for which they may not applicable. As mentioned earlier, the wide misinterpretation of Gladwell's Blink comes to mind. Nevertheless, Thinking Fast and Slow is a very valuable book by one of the most creative minds in psychology. Highly recommended. For a more complete and critical understanding, I also recommend the writings of the critics of behavioral economic models such as Gerd Gigerenzer. PS. After I published this review, I noticed an odd coincidence between Thinking Fast and Slow and Inevitable Illusions that I mentioned in my opening paragraph. Both books have white covers, with an image of a sharpened yellow pencil with an eraser top. How odd is that?

There are an increasing number of books that provide insight into how our minds work. Emotional Intelligence by Daniel Coleman and The Wisdom of Crowds by James Surowiecki are two good examples. Daniel Kahneman, in Thinking Fast and Slow, picks up that theme and advances it by an order of magnitude. In my view, this is the must read book of the year, and absolutely required read for anyone over fifty. Each of us know that there are parts of our brain that toil away ceaselessly regulating breathing and blood pressure, managing digestion and keeping our heart beating on schedule without us being consciously aware of it. From other books like Emotional Intelligence, we know that there is also a high-speed circuit that responds to stimulus far faster than conscious thinking. There are numerous examples. Touch something hot with your hand and you'll move it before you actually feel the pain. See someone you know in a busy airport or train station? Not only will you recognize them instantly, you'll know if they are sad or angry - our brains are hard-wired with high-speed circuits for facial recognition. Mr. Kahneman, through a series of examples, tests, incorporation of original research and reports of research from others, informs us that our autonomous brain does far more, including a lot of things that we should be doing with our conscious thoughtful brain, but we don't. He uses the term System 1 for the autonomous function and System 2 for our thoughtful, conscious brain. System 1 is fast, intuitive and emotional. System 2 is slower, more deliberative and more logical. Read the book and you'll know that System 1 is doing a lot of stuff. Most is either critical and performed well, or performed poorly but unimportant, but a certain part is done because of laziness or a concentration failure on our part, and would be much better managed by System 2. The first few chapters are reasonably easy read and full of interesting little quizzes. You'll probably answer some of those quizzes wrong, and it will be because you let rapid-fire System 1 come up with the answer instead of deliberating with System 2. One of these tests (I won't give it away) was given to a class at Princeton, conceivably some of the best and brightest in the country, and a majority of them failed, so don't feel too bad if you fail it also. However, I must warn you that the content gets harder. I'm reasonably literate in at least basic statistics, and I found myself challenged a number of times. On more than one occasion, I didn't understand the answer even when Kahneman gave it to me. After proving to us that we let System 1 interfere when it shouldn't, Kahneman provides chapters on our various thinking and logic errors and guidance on what to be on guard for to make sure we put System 2 in charge, and we prevent the vast number of thinking shortcuts that lead to suboptimal decisions. There are chapters on how a tired and overloaded brain makes bad decisions. How we tend to be poor assessors of risk, overly concerned about low probability events and not sufficiently concerned about riskier activities. This extends into how humans make investment decisions. I found the chapter on "Anchoring", that is, how we attach value to a reference number, even if we shouldn't, particularly useful, and very valuable when approaching a negotiation. There is thoughtful, research-based advice on when to rely on an "expert" and when not. Why do I say that this is a must read for anyone over fifty? Let's face it. Once we've crossed that line - maybe fifty for some of us, sixty or even seventy for others, we simply don't think as fast. Do you watch the famous game show Jeopardy? Generally I can hold my own with many contestants. I know a lot of the answers. However, I also know that I can no longer come up with those answers fast enough. The contestants buzz in way too fast for me. There is research on the ability of us in our second fifty years to make wise investments. It turns out that not too many of us are Warren Buffet. We need to be cautious and thoughtful when putting our money to work. This book provides very valuable insight into our unconsciously lazy mental habits and equally unconscious thinking errors. It is a must-read.

Daniel Kahneman is a renowned psychologist, who won a Nobel Prize in Economics. His work (and that of his late partner, Amos Tversky), and that of a network of colleagues in a similar path, has had an effect on how we see human decision-making. In the social sciences and economics, rationality is a key assumption about human thinking. Kahneman and Tversky and others have put that assumption in the cross hairs of their research. Indeed, some of my own research in political thinking by American citizens is based on this body of work. In this work, Kahneman begins by noting two systems of thinking. System 1 is automatic, quick, and intuitive. It is decision making by shortcuts. Normally, it works fairly well, but it can also lead to bad decisions. When the stakes are low, even the downside isn't too bad. For major decisions? Well, that can be problematic. The operations of System 2 are (Page 21) "often associated with the subjective experience of agency, choice, and concentration." This is the realm of reason and conscious thinking. System 1 tends to be nonconscious. Part I considers more deeply the operation of Systems 1 and 2. We learn, for example, that System 2 can be lazy and let System 1 "do its thing" without conscious control over those processes. Part II addresses biases in decision making. This includes the operation of decision making shortcuts, or "heuristics." These are tools that assist decision making and make it quick and easy--and sometimes very wrong. For instance, the law of small numbers. Many people are very confident that judgments that they make based upon a few examples are apt to be correct--even though there is scant statistical indication of this. We do not easily think in terms of probability and statistics. Or availability. We often make decisions based on what pops into our short term memory first, that which is most "available" for retrieval. Or regression to the mean. If someone scores extremely high on the GREs, it is common that the next test would result in lower scores. Why? Many times, very high scores are the result of good luck. Reality will return in such cases, as the next score is likely to revert to a more normal result. Part III? A series of chapters on overconfidence. It is disconcerting to realize that a lot of our decisions are based on shortcuts that can sometimes go way wrong. Worse, there is plenty of research that shows that once people make decisions, they become overconfident in how good those decisions are. Part IV examines choices. One of the more powerful aspects of Kahneman's and Tversky's work is "prospect theory." Once more, we see skewed decision making at work--far from the realm of rational cost benefit calculators. One key finding here: People tend to be risk averse when they are in positive ground; people are risk takers in negative situations. Example: If you are getting an A in a course and anticipate that that will be your final grade, you are unlikely to cheat. Why? You have a lot to lose and little to gain. On the other hand, if you're facing a D or F, you are, according to many studies, more apt to cheat. The relevance? Some urge being touch on cheaters as a way of deterring academic dishonesty. But someone who is in bad shape to begin with is less likely to be deterred in such a circumstance. The last part is a reflection on the meaning of all that went before. Also helpful is that some of the major pieces of research are attached as appendices. These may be slow going for some people, but if the reader can wade through them, they get a good sense of how this book came to its conclusions. A very fine book, well written, that makes important research accessible to a larger audience.

Very interesting, well written, but a very pessimistic view of intuition. The introduction to the book is long and wordy, and could be better written and more concise. I happened to read chapters 1 and two first and was quite excited about the book, but then I read the introduction afterwords, and that's what showed the naked truth about the perspective the author has about intuition. I don't disagree with what the author is saying, and it appears to be a well-written book, and I imagine the research behind it is thorough, however, the authors have left out a huge aspect of life. This book appears to be a non-spiritual view of intuition. The discussion is contained within the realm of cognitive and social psychology and does not reach outside of that. To me this is a huge bias and ioversight, and it is the mistake that many scientists have made for hundreds of years. I'd like to believe, and I think we have, progressed beyond such a limited point of view , to include aspects of life that are not contained within just western scientific thought. Spirituality is a huge part of intuition . I can think of times where I had intuition that was spiritually based, not based on any a priori indicators whatsoever . So how do you explain that kind of intuition? So, I can only recommend this book from the point of view of cognitive and social psychology but not beyond. If you're looking for more, this is not the place to find it. The book appears to be useful, but definitely an incomplete perspective on intuition. What I have read so far, has left me with a weird combination of both excitement and let-down. I will likely read more of the book, but not without supplementing it with other more- inclusive studies of intuition

Personally I think this is a great book because it opens a new perspective. Many human behaviors can be explained well in the "System 1 vs. System 2" framework. However, I think System 1 has more depth. Simply labeling System 1 as "intuitive" and even "irrational" is not sufficient. We may want to find out why System 1 acts that way, and also its strength and weakness. One important characteristic of System 1 is it often uses relative measure instead of absolute measure. Long before the computer era and even long before human civilization, humans had started gathering information from their environment, storing it and processing the stored information to help them make decisions. At that time, the amount of information, information storage space and information processing speed were all very limited. On the contrary, the decision making process needed to be fast, probably faster than today's average, considering the harsh environment at that time. Therefore the human brain developed some outstandingly smart strategies to cope with that situation by retaining the most important information and using it in the most efficient way. One of the strategies is use relative measure instead of absolute measure. Relative measure is easy to obtain, taking less space to store and easier to use for decision making when options are limited. Very often relative measure does not mean comparing two things on the table, but comparing a measure to a reference value. The reference value is often the prior expectation. One would assess the value with newly acquired information and compare it with the prior assessment: That is exactly the idea of Bayesian inference. For example, when a primitive man encountered with an unfamiliar animal, he would constantly watch the of the animal's behavior and judge if that behavior makes the animal more or less likely to be dangerous and act accordingly. Assessing the absolute dangerousness would be a less urgent task. In the famous "Linda problem", many people think that "Linda is a bank teller and is active in the feminist movement" is more probable than "Linda is a bank teller". It is an obvious logical fallacy. However, it could be explained by the tendency of using relative probability measures. Considering Linda's personal traits altogether, she looks more probable to be a "bank teller and feminist" than an average person; but less probable to be a bank teller than an average person. So both probabilities here were normalized by the prior expectation: Relative probability that Linda is A = P (Someone is A| given someone has Linda's traits) /P (Someone is A) In our daily analytical process, the priority is usually making the best use of newly available information rather than finding the things with higher probability. No one would state: "the sun will rise tomorrow"; but many people would pay attention if some one says "I sense that something might be wrong", even the probability that something is wrong may be less than 0.5. Even we use relative measure very often; we are not always fully aware of it and not very conscious of what reference point we are using. In many cases, the reference point is the most recent observation (Chapter 17 "Regression to The Mean"). Since human psychology tends to put a lot of weight on the improvement (or measure relative to most recent data). For example, we tends to be happy when we are becoming wealthier, the sign of change is often more important than the absolute value of wealth to our happiness. It is understandable because in early human history, our most important learning experience is trial and error, whether there is an improvement was the most important criteria. But the improvement is not the best measure in some cases. For example, you may want to know if a good score helps next performance by giving confidence or hinders it by adding pressure. A series of scores read (I made it up): 10, 8.6, 5.9, 4.7, 3.7, 5.5, 1.2, 3.2, 3.7, 6.2, 6.6, 7.3, 5.5 The average score is 5.55. So there are 6 "good" (above average) and 7 "bad" (below average) scores. There are 8 out of 12 cases that good score followed by deterioration or bad score followed by improvement, which is compatible with mean regression explanation pointed out by the author. However, does this mean that good score is more likely to hinder your next performance? No. Actually the data indicates the opposite. The correct measure of performance should have a fixed reference point (average score in this case). And here we see that good performance tends to be followed by good performance or bad performance tends to be followed by bad performance (9 out of 12 in this data set). So it actually means good score tends to boost next performance (autocorrelation is 0.59). In summary, using relative measure was an optimized strategy in human's early age. It is still the best strategy today most of the time today. Using relative measure, together with many other functions of System 1, have been the primary choice of our analytical process. They are hard wired and we call and run those functions fast and with little effort (that is why we are often not fully conscious about the process). This characteristic of our brain should have played an important role in the survival and development of our specie. However, the primary choice is not always the best choice. Now being able to access to more information, larger storage space and stronger computing power, we might want to be a little more conscious when making choices.