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How We Know What Isn't So: The Fallibility of Human Reason in Everyday Life
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How We Know What Isn't So: The Fallibility of Human Reason in Everyday Life

3.94  ·  Rating Details ·  2,143 Ratings  ·  78 Reviews
Thomas Gilovich offers a wise and readable guide to the fallacy of the obvious in everyday life.

When can we trust what we believe—that "teams and players have winning streaks," that "flattery works," or that "the more people who agree, the more likely they are to be right"—and when are such beliefs suspect? Thomas Gilovich offers a guide to the fallacy of the obvious in ev
Paperback, 216 pages
Published March 5th 1993 by Free Press (first published 1991)
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Sep 22, 2009 Trevor rated it it was amazing
I thought this was a remarkable book – five stars all the way – up until the last couple of chapters when it really didn’t live up to its initial promise. But I’m giving it 5 stars anyway, because the first two parts are so good they are more than worth whatever effort is necessary to get your hands on this.

It is a bit old now – first printed in 1991, but many of the ideas are still essential if you have any interest in how our judgement and decision making processes can land us in trouble.

The f
Aug 06, 2014 Shannon rated it really liked it
This book examines cognitive biases. Gilovich describes various dubious beliefs, such as faith healing and other homeopathic nonsense. He investigates the thought processes that affect our ability to make sound judgments. It encouraged me to examine the shortcomings of my own reasoning. Highly recommend.
Jan 20, 2012 Steve rated it really liked it
This is a really excellent book, though there are a lot more engaging reads in the psychology-for-general-public read as of late. If there weren't so many better written ones as of late and the book itself weren't nearly twenty years old old (I am hoping for a second edition), I'd have given it five stars (there's more research on how people think and decide more recently). Unfortunately, lately, I've been meeting lots of people endorsing truly ridiculous ideas without thinking critically about ...more
Jan 05, 2016 Jacob rated it liked it
This is a good solid work about people's irrational beliefs, covering just about all the basic psychological mechanisms. It's not breaking new ground, but that's because it's more than 20 years old. Still, it brings a few things to the table that I haven't seen in most other discussions of this topic:

- The authors recognize that while we see many occasions when people form opinions that are incorrect or at best not supported by (complete & unbiased) evidence, human nature leads us to make go
How We Know What Isn't So is a researched book on social psychology by Thomas Gilovich, a psychology professor at Cornell. It talks about why our mind seeks dubious or erronous information to aid our biases, rather than negating or clarifying them, and supplements its claims by examples of researches that did so in the past.

Reading this book would help you to look at the usually pervading superstitions and medical 'quacks' or evidence in support of existence of paranormal activities, or any oth
Apr 03, 2008 Dfordoom rated it it was amazing
Shelves: non-fiction
Author Thomas Gilovich gives us concrete examples of the ways in which people can come to believe things for which there is no genuine scientific evidence, and the common errors people make when trying to make sense of statistical and probabilistic data. He shows us how people can consciously or unconsciously delude themselves, and how we so often ignore evidence we don’t like and concentrate on evidence that appears to support views that we want to believe are true. The book is moderately schol ...more
Nov 05, 2011 Sue rated it it was amazing
This book makes you think about how unthinking we are, from believing that infertile couples are more likely to have a biological child once they have adopted one.(not too many consequences here) to belief that seal penises are the natural Viagra, (40,000 seal penises found in one raid). We tend to notice only those events which reinforce our own beliefs and prejudices - we ignore evidence which disproves them. Every statement is peppered with entertaining real-life examples including an explana ...more
Jake Losh
Sep 02, 2015 Jake Losh rated it it was amazing
Shelves: non-fiction, psych
This is an exceptional book. I got about six chapters deep into it several months ago when I decided that I was trying to read it way too fast. At under 200 pages (excluding notes and references) this is an extremely dense and comprehensive treatment of so many aspects of human reasoning. This book is intense and will make you question so many things about the way you see the world. Once you start to read it, you'll start to see the application of its lessons everywhere and you cannot unsee them ...more
Feb 01, 2008 Kyle rated it it was amazing
Recommends it for: amateur psychologists, skeptics, critical thinkers
How We Know What Isn't So is an outstanding read for anybody who tends to be a skeptic or merely wants to be a critical thinker. While the author is an academic, the book is well-written and actually a fairly quick and easy read. The purpose is to explore how we come to understand things, and primarily it focuses on how we come to believe things that are not true. Whether it is ESP or alien abductions or more common myths like strange things happening during full moons, Gilovich documents a wide ...more
Sarah Whitney
Apr 23, 2010 Sarah Whitney rated it it was amazing
Shelves: non-fiction, a-gift, own, 2010
Gilovich is an impressive academic and skilled writer. I really enjoyed this book, especially part II. I'd recommend this for anyone who is interested in the validity of their beliefs and the science behind how people form cognitive biases. Reads a bit like something you'd be assigned in college and it is quite scholarly, but in a very nice way, with citations galore. I previously read "Don't Believe Everything You Think: The 6 Basic Mistakes We Make in Thinking" by Thomas E. Kida and was disapp ...more
Jan 04, 2015 Olga rated it really liked it
It's a good complementary reading with another book "Mistakes were made but not by me" by Carol Tavris and Elliot Aronson, where both books attest human fallibility to consider their biases in offering reasons to different situation with seemingly unexplained phenomena and so taking early and foolish arguments and transform them in believes without looking upon scientific and statistical justification of everyday experiences and logic fallacies.
Jonah Keri
Jan 23, 2009 Jonah Keri is currently reading it
Just getting going on this one. It's long been on the wife's bookshelf and was widely read in Baseball Prospectus circles by folks with an interest in learning how the human mind operates and how fallacies coming into play. A bit of a Gladwell edge to it, I'd say.

Long flight to LA this weekend, should plow through a good chunk of it.
Aug 31, 2013 Troy rated it really liked it
I found this a very informative discussion of the many ways our brains can persistently mislead us into erroneous conclusions via otherwise perfectly normal, useful and effective psychological processes.
Todd Martin
Jul 21, 2014 Todd Martin rated it really liked it
“People will always prefer black-and-white over shades of grey, and so there will always be the temptation to hold overly-simplified beliefs and to hold them with excessive confidence.”
- Thomas Gilovich

When it comes to critical thinking, people seem to suffer from the Dunning–Kruger effect - a cognitive bias in which unskilled individuals suffer from illusory superiority, mistakenly rating their ability much higher than is accurate. In other words … everyone believes they are critical thinkers,
Richard Houchin
Jan 06, 2011 Richard Houchin rated it really liked it
Shelves: philosophy, history
This review has been hidden because it contains spoilers. To view it, click here.
Oct 19, 2016 Cristobal rated it really liked it  ·  review of another edition
This is a must read for those interested about cognitive bias. It will serve as a fantastic companion to "Thinking Fast and Slow," although if I could only read one of the two I'd go with "Thinking Fast" since it much better structured and easier to understand.
Dan Carney
Feb 02, 2010 Dan Carney rated it really liked it
I read this book because I thought the quote prefacing the first chapter was immediately worth considering:

The trouble with the world is not that people know too little, it's that they know so many things that just aren't so.

I want to understand the trouble with the world, who wouldn't? And where better to start than ignorance? After reading this, I'd have a fighting chance of being able to easily identify ignorant folk hiding in everyday conversation, using carefully crafted deception to keep o
Kelly Wagner
Jun 29, 2013 Kelly Wagner rated it it was amazing
Even though this book is over 20 years old and there's been a lot of research in psychology and neuroscience done in that 20 years, this book is still as good a summary of how we deceive ourselves about what we're thinking, about what we base our decisions on, about how we evaluate risk, as any of the books published this past couple of years. Gilovich is an extremely clear writer, and gives exactly enough examples. He explains the biases that creep in when we are evaluating the amount of inform ...more
Ali Reda
Sep 05, 2014 Ali Reda rated it liked it
When examining evidence relevant to a given belief, people are inclined to see what they expect to see, and conclude what they expect to conclude. Information that is consistent with our pre-existing beliefs is often accepted at face value, whereas evidence that contradicts them is critically scrutinized and discounted. Many psychologists believe these phenomena stem from truly motivational processes: We hold such self-serving beliefs because they satisfy important psychological needs or motives ...more
Feb 20, 2016 Sancho rated it liked it
I'll start with some quotes that I liked:

"Information that is consistent with our pre-existing beliefs is often accepted at face value, whereas evidence that contradicts them is critically scrutinized and discounted. Our beliefs may thus be less responsive than they should to the implications of new information."

"People will always prefer black-and-white over shades of grey, and so there will always be the temptation to hold overly-simplified beliefs and to hold them with excessive confidence."

Jul 08, 2007 Erik rated it it was amazing
I first heard about this book in Usenet conversations where a group of wickedly smart people were developing the principles of baseball analysis that would become the new wave of baseball management. Building on the work of Bill James, those people insisted on testing the validity of long-established nuggets of conventional wisdom that often didn't stand up to scrutiny. When skeptical readers asked how the widely accepted values of professional baseball players and management could be so wrong, ...more
Pete Jones
Dec 05, 2013 Pete Jones rated it liked it
My doctor recommended that I stop reading exciting fiction and instead read something boring before going to bed. This book seemed to fit the bill. It worked. Not that it’s boring, it’s just not exciting and it’s easy to put down.

Unless you’re heavy into statistics and psychology, this book is probably not for you. My BS is in statistics and the author’s “regression for dummies” leaves a lot to be desired. The book is heavy in statistics in the beginning and gets squishier as the book moves from
Blake Nelson
Mar 03, 2010 Blake Nelson rated it really liked it
This book tries to answer the question "why do be believe what we do", in particular, why do we believe things that are demonstrably false. Why do people believe in ESP, or bigfoot, or alternative medicine (a great quote from Tim Minchin: "You know what they call alternative medicine that’s been proved to work? Medicine.”)? Why were people terrified of shark attacks several years ago, but complacent about the risks of getting to the beach in the first place?

The description of the studies used wa
Hom Sack
Apr 22, 2016 Hom Sack rated it it was amazing

Instructive, persuasive, and well argued. The book is entirely an enjoyable read. I like especially the last paragraph:
... Much that we currently know about what is or isn't so will surely change in subsequent years. What is most important, then, is not dispelling particular erroneous beliefs (although there is surely some merit in that), but creating an understanding of how we form erroneous beliefs. To truly appreciate the complexities of the world and the intricacies of human experience, it
Art King
Apr 06, 2013 Art King rated it it was amazing
In the few weeks since I finished reading this book, I've had several marvelous, thought-provoking discussions with friends on the ideas presented here.

This book reminds me of one of the most important lessons: I make mistakes. I overestimate how often events which receive big media coverage actually happen. I magically find patterns in random data. I believe things I want to believe while sharply questioning contradictory information. "How We Know What Isn't So" explains why, and gives me tools
Nov 01, 2015 Malli rated it really liked it
I got onto Thomas Gilovich's book as his works and papers are referenced in Kahneman's Thinking: Fast and slow. The first two sections of the book where Gilovich brings forth some of the big biases in our reasoning are brilliant. He lost steam in the latter two sections that are rants against Faith Healers and ESPs. Sure, there is possibly much that is bogus on these dark arts. But then does it warrant that half the book be devoted to this rant? Despite a poor second half, I feel the brilliance ...more
Frank Jude
Jun 21, 2013 Frank Jude rated it really liked it
This is a wonderful book; perhaps even an important book. It reveals why reasoning so often goes disastrously wrong by uncovering the cognitive errors based upon inference, naive assumption and probability illiteracy.

The thing is, of course, is that when we are made aware of such errors and their causes, we can finally take some precautionary measures! This book is a clearly written example of how we can learn to think about thinking. "It ain't so much the things we don't know that get us into t
Stephan Köhler
Dec 21, 2012 Stephan Köhler rated it liked it
A nice introduction to the cornerstones of sceptical thinking and the errors in reasoning we are prone to commit.

Some parts can be rather dry if the reader is already familiar with the basics of scepticism and logical fallacies but it can serve as a nice primer for those who aren't.
What is also interesting is that the book was written over 20 years ago and still deals with most of the same issues that are discussed today.

All in all a worthwhile read for the novice skeptic.
Nov 21, 2011 Megan rated it it was ok
Shelves: didn-t-finish
This is interesting material, but I couldn't get all the way through the book. Too dry. Too academic. Also, as this is an older book, the ideas aren't new anymore. More recent material, including books on randomness (The Black Swan), books by Malcolm Gladwell, and the Freakonomics books, cover many of the same ideas. The main point seems to be that humans can't be random and can't necessarily interpret data well; also, that even when we have the data before us, we don't always believe it.
K.H. Vaughan
Nov 08, 2013 K.H. Vaughan rated it it was amazing
A clear and illuminating book on the limits of human judgment by an expert in the field. Everyone would benefit from a basic understanding of the limits of human cognition. There are some things we are good at and some that we are not. Unfortunately, we don't have good insight into which are which. Very readable and requires no background knowledge. If you enjoyed Innumeracy, this is a fine companion.
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From Wikipedia:

Thomas D. Gilovich (born 1954) is a professor of psychology at Cornell University who has researched decision making and behavioral economics and has written popular books on said subjects. He has collaborated with Daniel Kahneman, Lee Ross and Amos Tversky.

Gilovich earned his B.A. from the University of California, Santa Barbara and his Ph.D. in psychology from Stanford University
More about Thomas Gilovich...

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“When examining evidence relevant to a given belief, people are inclined to see what they expect to see, and conclude what they expect to conclude. Information that is consistent with our pre-existing beliefs is often accepted at face value, whereas evidence that contradicts them is critically scrutinized and discounted. Our beliefs may thus be less responsive than they should to the implications of new information” 25 likes
“People will always prefer black-and-white over shades of grey, and so there will always be the temptation to hold overly-simplified beliefs and to hold them with excessive confidence” 21 likes
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