Predictably Irrational: The Hidden Forces That Shape Our Decisions

by Dan Ariely

Paperback, 2009


Harper (2009), Edition: Revised, 304 pages


An evaluation of the sources of illogical decisions explores the reasons why irrational thought often overcomes level-headed practices, offering insight into the structural patterns that cause people to make the same mistakes repeatedly.

User reviews

LibraryThing member StormRaven
Traditional economic thinking is built upon the idea that people are essentially rational, and upon that foundation it constructs demand curves, supply curves, elasticity functions, and a vast number of other concepts. In recent years, however, a group of economists, often with training in the
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field of psychology, have begun to test and challenge some of the foundational assumptions of economic theory. This field is known as "behavioral economics", and unlike much of traditional economics, it incorporates field experiments into its repertoire in order to test the questions posed by human behavior. Predictably Irrational is Dan Ariely's enjoyably readable introduction to the field of behavioral economics, and one of the more interesting conclusions that this branch of economic study has to offer: people are not rational, but they are irrational in consistent and predictable ways.

[More forthcoming]
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LibraryThing member pbirch01
This is another great example of a great idea that would make an excellent long article in a publication such as the New Yorker, but instead gets overstretched into a book. Ariely uses many unique studies to highlight the seemingly irrational behavior of people, well actually only people in Boston,
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Chapel Hill, and Berkeley. Anyways, his studies are well thought out and generally pretty interesting. However, after about the midpoint the book starts to fall apart. The studies outcomes are easily predicted and the light, fluffy prose soon becomes heavy and plodding. While the book altogether makes some interesting observations based on studies, the material is stretched so thin I felt I was being a bit irrational in trying to finish it.
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LibraryThing member datrappert
Interesting and much better researched than Malcolm Gladwell's books, Ariely's story of how irrational most of our decisions are doesn't come across as a surprise, but it is depressing, nevertheless. As he narrates tale after tale of people making irrational decisions, you'll see yourself time and
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again. What is most interesting is how by varying his experiments just a little, he can produce significantly different results. Sad to think that we aren't generally honest unless we are being watched -but I'm afraid he is right. The other depressing thing is just how poor we are at gauging the extent of our irrationality, even when we understand that there are situations, such as when we are sexually aroused, when our decision-making powers are weakened. Throughout the book, Ariely's sense of humor and self-deprecation make for an engaging read (or listen in my case.)
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LibraryThing member JollyContrarian
Predictably Anecdotal

Blame Malcolm Gladwell - but after Blink: The Power of Thinking Without Thinking social psychologists of the type he featured in that book have been coming out of the woodwork to publish in the pop science market in alarming numbers figuring, reasonably, enough that there's a
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bit of money to be made on the side. I'm guessing royalties from articles in the International Journal of Psychology would pale in comparison.

One of the latest is Dan Ariely, whose unique selling point is a horrific accident he sustained as a student Israel which left him with burns to 70% of his body. His book does what it says on the tin, by way of explaining a number of social experiments that he and his colleagues have run in the last few years, loosely themed around the observation that we don't always act as sensibly as logic would dictate.

Which is fine - as you would expect, some of the examples are eyebrow raising - but it really shouldn't be news and it certainly doesn't require Dan Ariely to tell us that our liberal western societies aren't as rational as we like to think (incontrovertible proof of that, not offered in Ariel's book, being the politicians we elect and the amount of attention and money we collectively devote to cosmetics, fashion, celebrity and professional sport), especially as deeper epistemological examination reveals the idea of "rationality" is incoherent anyway.

But just as some anecdotes are enlightening, the implications of others are not nearly as plain or convincing as Ariel thinks they are, and some of his experiments struck me as being particularly glib, superficial and susceptible to plenty of alternative interpretations.

And what Ariel's book lacks is any further theoretical drive: OK, we re predisposed to behave in silly or odious ways - but what's your point? In what underlying way are our irrational proclivities linked? What conclusions can we draw; what can we learn; what strategies can we adopt to counteract the harmful effects of our fecklessness?

Ariely implies, but doesn't say, that some sort of regulation is required to save us. But given that it was our irrational proclivities by which we arrived at these politicians (and the political institutions through which they organise themselves) I'm not sure he leaves us any better off than when we started.
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LibraryThing member wvlibrarydude
Interesting read, but a little light. I was taken back by how little he cited outside of his own work. He does toot his horn a tad too much. Still an interesting look at different decision making habits for people. I would have liked more research to back up the conclusions (some were a leap).
LibraryThing member fingerpost
A very easy-reading non-fiction title about how we, as humans, do not act rationally in many situations. In fact, we act irrational in the same ways, and we do it over and over. Dan Ariely has concocted an assortment of fascinating experiments to test why we do these things, and the descriptions of
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the experiments make up the bulk of the book. Fun and interesting.
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LibraryThing member MikeInKennebunk
Ariely's observations about the quirks human behavior are very interesting because they are supported by experiments and data. I appreciate his easy-to-read style but the number of experiments and their lengthy descriptions get boring pretty quickly. Each chapter starts with an interesting
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hypothesis, but then he wades into plodding descriptions of various experiments and their variations. Good book, but I would only recommend it to somebody VERY interested in consumer behavior and not afraid to read something more akin to a text book.
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LibraryThing member jpsnow
This is the closest thing I've seen to an "economics page-turner." Every chapter is based on interesting experiments he's conducted that show how we're not as rational as economics has always assumed. We're at least consistent and able to break the patterns once we understand them.
LibraryThing member amadouwane
Anchors: Irrelevant suggestion that prime us to make certain choice. Example of a numerical priming is using an individual social security number to prime him/her to pay a certain price of an item.

Relativity. Our preferences are relative. We compare ourselve to others and decide if we are better
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off than them. Shifting the context of the comparison result in different reaction in people.
The power of zero in pricing. A free offer can steer us away from a good choice.

Market Norm vs Social Norm:When we mix social norm with market norm, the social norm will be lost. A company may advertise that they treat their customers as family members. But when they need to charge late fees, the customer feels that they violated the social norm. The advice to company is to stay clear of social norms and not mix the two.

We spend too much energy contemplaiting our options and trying to keep them open. We don't take to account the consequences of not making any choice.
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LibraryThing member stefferjo
This was a fun read. The author uses simple experiments to discover the reasons that people make strange (sometimes bad) decisions. For an MIT professor, his writng is surprisingly understandable at the layman's level. While this book didn't change my life, it did make me think. The author's ideas
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on possible changes to the education system, health care system, and managing credit are progressive, but it will take a lot more than this to bring about the changes.
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LibraryThing member feistyscot
I was disappointed. I realize it's nigh on impossible to present the results of dozens of experiments in a layman's introduction to the topic, but still I had the feeling all along that the author was drawing conclusions that weren't robustly supported by the evidence. Frequently he describes the
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results of an experiment, then follows this with "this experiment shows X", when it may well show nothing of the sort. Without knowing something about his methodology, though, I'm not able to say anything more. All in all I'd say that the book misses the mark as a book for the sophisticated layman, as it leaves too much out, or too much unexplained, to be stimulating. Assuming the various results he describes are well-supported by the evidence, they are fascinating. But I could've learned as much about them by reading wikipedia as by reading this book.
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LibraryThing member tedxprada2004
It is readable. Dan used simple language to write this book. We understand more our irrationality.
LibraryThing member Antholo
Predictably Irrational is Interesting and thought provoking, and I overall enjoyed this book. The general idea, if you haven't picked this up elsewhere, is that people do not always make the most rational choice of all available options, and we are in fact consistent in making certain irrational
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decisions. Our brains can be fooled, can be unreliable, and can fail to help us make the choices that would be in our best personal interests.

Two criticisms:
1) This applies only to the audiobook version, as it concerns the reader. It took me some time to get used to the reader--initially, I was considering dropping the audio and reading the codex version. I waited it out and I'm glad I did.

2) While the author describes some amazing studies (some amazing for their complexity, others for their simplicity, all for their challenging of established assumptions), I was surprised at the few times he threw out suppositions semi-related to the conclusions of a particular study.

Those two criticisms aside, I would recommend this book to others. I wish I'd had the option of learning more about behavioral economics when I was working on my econ degree. I'd be willing to have a chat about it with anyone else who'd be interested.
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LibraryThing member emily.steed
Basically, this book seemed like a low-rent Freakonomics. Not as amusing, slightly less interesting, a little drier. It was the same basic format: odd situation, hypothesis, description of experiment, analysis. Lather, rinse, repeat. Some of what he had to say was interesting, but for the most part
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the conclusions he reached seemed pretty obvious in the first place. For example, people are more willing to steal when they're not stealing cash, and they steal more when what they're stealing is more removed from cash. (The example he gives is office supplies - someone is more likely to take a pen worth $0.10 from the office than they are to take $0.10 from the petty cash jar. This seems pretty obvious to me...)

If you were going to read one behavioral economics book, I'd skip this and read Freakonomics instead. If you like Freakonomics and wanted to read another, this wasn't as good but it's a quick read and interesting enough.
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LibraryThing member WinterFox
I don't think anyone would argue with the claim that people aren't totally rational. Even in areas where we should be looking after our own interests, we don't always do so. There are probably interesting ways to look at this, and I think this book does a decent job of it. The problem is that it
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only does it about half of the time, and the rest, it just seems obvious.

For example, things I was surprised by included how much difference it makes for something to be free, rather than just a penny, or the influence that a decoy offer can have on one's decision making process. Even the portion on the costs people pay to keep options open was enlightening. Others among the studies just seemed like the sorts of things we already knew, and they're just going ahead and proving it. So things like people thinking differently when they're very emotional than when they're not, or that foreknowledge and expectations can lead to people experiencing things differently, doesn't really come as a shock.

Still, the book is fairly nice and breezily written, and Ariely's a clever guy. The experiments he comes up with are usually fairly interesting, even if the points they're proving aren't always. I'd have liked it better if he'd stuck with about half the book, and left out the more obvious bits, but it's still a good read, and it won't take you long. I'd wait for the paperback, though, if you're going to buy it.
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LibraryThing member bferster
An interesting review of the literature in behavioral economics by a leading researcher in the field.
LibraryThing member madcurrin
I really wanted to find this book profound but it stopped a bit short for me. Perhaps I was just hoping for some genius short cuts to winning in life, an unfair expectation to put on a book.

Expectations aside, this is an easy read, written by a candid and cheerful author who raises some good
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honest questions that should be considered by everyone from employers to politicians. The book also kicks off with some eye opening insights into why we all fall for cunning sales pitches. (I must confess I skipped through the chapters on American health care, not being American myself.)

All up, an interesting book that doesn't quite feel as important as it looks like it should be.
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LibraryThing member ivirago
I enjoyed this - well worth a read. Some interesting experiments talked about in this book - particularly made me think about the rigour that's involved in trying to make sure your observations are valid - hard work!
LibraryThing member flydodofly
Why do we do things? This book is an attempt to answer this question. Interesting and never overwhelming, it was a refreshing read.
LibraryThing member Ramirez
As Freakonomics this book is conceived to appeal to the great public: anyway it's a lor better than Levitt's, well written and complete.

The main message is that traditional economics suffers a huge misunderstanding of human nature: in fact it assumes that men are rational agents, acting on the
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behalf of a cost/benefit analysis whenever they decide.

This is far from reality.

Humans are irrational. Most of the time our decision making is influenced from a huge number of factors (e.g. the context for a comparation, our former experiences, our expectations, and so on).

It may seem a bit depressing, but consider this: being our irrationality a very systematic and predictable flaw, we may take steps in order to prevent ourselves from make bad decisions, and -more important- shape our policy and law-making to this state of things.
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LibraryThing member wbc3
A fun book which gives a good look at the "other" side of economics. Rather than looking at people as rational actors who always maximize their utility, behavioral economics tries to find out what makes people behave the way they actually do. Ariely and his friends seem to have an oddball
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experiment to test just about everything. How many economists give away beer in Chapel Hill to see how one person's order affects another's? (It turns out that in America, people will choose their beer to be different from other people at their table, even if the beer is one the person likes less. Good ol' American individualism in action!) Ariely then tries to take each principle he uncovers and apply it to how we should act and govern. In the beer example, he says that you should decide your order before you hear what everyone else wants to order. It is in these conclusions that the book is a bit weak. The book, however, is well worth reading as at least one of the chapters is likely to trigger something in how you live or view others.
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LibraryThing member ebnelson
From a theological standpoint, this is a great look at total depravity. Uses study in behavioral economics to demonstrate how fundamentally broken humanity is, while writing with wit great insight. Broad range of important topics from consumerism to sex to child rearing. Very important book. Highly
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LibraryThing member woodge
This was a pretty interesting book, interesting enough to finish, but maybe not so much that I read it to the exclusion of all else. Regardless, I learned some cool things about how irrational we all are. Things like the effect of a thing's price on our decision to buy it or determine its
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effectiveness... the influence of arousal on decision-making (careful there!)... overvaluing possessions... the effect of expectations... and our propensity to cheat when the option is available to us. The author details many little experiments that he and his colleagues used to bolster his conclusions and I was amused at how many of them involved beer in some fashion. Clearly he's a smart man.
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LibraryThing member lanes_3
This is a nice lead-in to further reading on behavioral economics. Ariely touches on this in his closing chapter, how much of the research that he discusses throughout the book is better studied from behavioral economics than pure rational economics. It is interesting to see how what some
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situations may seem call for rational decisions, the research evidence tends to show otherwise.
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LibraryThing member tjsjohanna
I found many of these behavior experiments really fascinating - who knew that changing the price of a chocolate from 1 cent to free could have such a huge impact on one's decision? or that signing an honor code directly before taking a test could dramatically decrease cheating behavior? We humans
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are certainly an interesting bunch. Now I'd like a book that teaches me how to go against that innate response!
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Original publication date



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