A fast-food chain once tried to compete with McDonald’s quarter-pounder by introducing a third-pound hamburger—only for it to flop when consumers thought a third pound was less than a quarter pound because three is less than four. Separately, a rash of suicides by teenagers who played Dungeons and Dragons caused a panic in parents and the media. They thought D&D was causing teenage suicides—when in fact teenage D&D players committed suicide at a much lower rate than the national average. Errors of this type can be found from antiquity to the present, from the Peloponnesian War to the COVID-19 pandemic. How and why do we keep falling into these traps?
James C. Zimring argues that many of the mistakes that the human mind consistently makes boil down to misperceiving fractions. We see slews of statistics that are essentially fractions, such as percentages, probabilities, frequencies, and rates, and we tend to misinterpret them. Sometimes bad actors manipulate us by cherry-picking data or distorting how information is presented; other times, sloppy communicators inadvertently mislead us. In many cases, we fool ourselves and have only our own minds to blame. Zimring also explores the counterintuitive reason that these flaws might benefit us, demonstrating that individual error can be highly advantageous to problem solving by groups. Blending key scientific research in cognitive psychology with accessible real-life examples, Partial Truths helps readers spot the fallacies lurking in everyday information, from politics to the criminal justice system, from religion to science, from business strategies to New Age culture.
ABOUT THE AUTHOR
James C. Zimring is the Thomas W. Tillack Professor of Experimental Pathology at the University of Virginia School of Medicine. He is the author of What Science Is and How It Really Works (2019).
"In this brilliant follow up to What Science Is and How It Really Works, James Zimring engages the reader in a kind of detective story about the classic mistakes of human reasoning, due to our innumeracy. From bad social policy to pandemics to terrorism, he shows how human decision making often gets it so wrong. What I loved most about Partial Truths though is that he didn't just establish that we make errors, but why. This amounts to a handy, insightful, eminently readable guide to the intricate evolution of the human mind itself. If you enjoyed Daniel Kahneman's Thinking Fast and Slow, you'll love this book.
--Lee McIntyre, author of How to Talk to a Science Denier
Available on NetGalley
Average rating from 7 members
Partial Truths: How Fractions Distort Our Thinking by James C Zimring is a very accessible look at the many ways we, as humans, undermine our own thinking and how many of these are related to our misuse or misunderstanding of fractions.
First, this is not a book of mathematics, so don't let that keep you away. Many of the ideas addressed have become widely known, or at least widely spoken of, such as confirmation bias. Zimring presents these in plain language and shows how they can be seen as part of our issue with fractions. Whether we only look at the numerator or denominator, whether we keep changing the denominator in order to keep the view we have, even whether we even realize we should be looking at a fraction (or relationship) rather than just a single number.
If you've read some of the scholarship, or even the popular books, on these topics you will recognize many of the broader topics. Whether your reading has been under behavioral economics, social psychology, or any of the other fields that have looked at our cognition, Zimring brings a fresh approach by working through the idea of the fraction. Many are literally about fractions while some are more relationships spoken of as fractions. But then, what are fractions other than relationships?
I would recommend this to anyone who wants to know more about how we all arrive at, and sometimes irrationally maintain, our viewpoints. To the extent that we can become a little less irrational we have to start from understanding what we are doing. This book goes a long way toward clearly illustrating the errors (not all of which are detrimental) in our thinking.
Reviewed from a copy made available by the publisher via NetGalley.
I enjoyed this book. The book is really about biases but uses fractions as a discussion point. There is not a lot of math in the book; what little there is, is explained very well. The book has a conversational tone and the author shares some personal perspectives, which I usually appreciate. The writing is quite compelling, with some humor and clever wording. The endnotes are also worth reading, however, the endnotes that contain clarifications on the text are mixed in with the endnotes that only contain references and citations. I find this annoying in many books. I much prefer that clarifications or explanations appear as footnotes on the same page as the content. I quickly stopped checking the endnotes but scanned through them at the end and many were worthwhile reading. While the pacing of the book was quite good overall, I found that the book slowed down when the discussion turned to cognitive psychology. Nonetheless, the book was so good overall that it still merits 5 stars. Thank you to Netgalley and Columbia University Press for the advance reader copy.