Partial Truths: How Fractions Distort Our Thinking
James C. Zimring. 2022. Columbia University Press. [ISBN 978-0-231-20138- 4. 244 pages, including index. US$28.00 (hardcover).]
In a world of exponentially growing data in all subjects, fractions and percentages are more important for both official and casual communication. In Partial Truths: How Fractions Distort Our Thinking, James C. Zimring claims that everything from scientific research to new age beliefs are distorted by bias created from numbers. By omitting sample size, failing to create appropriate data, or even manipulating existing data, our society derives faulty conclusions. His analysis of how and why this happens examines evolutionary human psychology and how misperceptions can lead to propaganda and polarization of society.
In this twelve-chapter book divided into three sections, Zimring lays out his arguments about data misperceptions. In Part 1, he explains how anecdotal evidence can persuade people with a sample size too small for valid conclusions, called “ignoring the denominator” (p. 17). A relevant example of this occurred when then President Trump claimed the United States had more cases of Covid-19 than other countries because we were testing more people. Trump ignored the denominator by failing to communicate that our rate of infection (cases per total number of people tested) was higher than other countries. Zimring goes into more depth on possible ways the data could have been collected and analyzed to derive different conclusions.
Presentation of data is just as important as our perception of it. Zimring’s focus on human psychology and perception renders his title choice a bit misleading—the book might more accurately be called Partial Truth: How Fractions and Human Psychology Distort Our Thinking. One simple psychology concept introduced and carried is that of a heuristic. “A heuristic is a process by which human minds rapidly solve complex problems by replacing them with analogous but simpler problems” (p. 32). These mental shortcuts can play tricks on our minds and influence how we formulate conclusions. Confirmation bias is another important psychological concept that “... is not a belief. Rather, confirmation bias is a process by which we reinforce our beliefs—any beliefs—regardless of origin or accuracy” (p. 42).
Part 2 focuses on how heuristics, confirmation bias, and other tendencies influence the interpretation of data that often leads to faulty outcomes. Focus areas include identification of criminals, invasion of Iraq, interpretation of coded messages in ancient texts, new age methods, evolution/natural designer arguments and, most importantly, the physical sciences.
Part 3 discusses how we can try to influence the way people think and avoid harmful polarizations of disagreement often based on the same available data. Methodology includes “epistemic network models” (p. 178) of actors in simulated social networks enacting various scenarios. Social networks analyze the effects of human tendencies, including confirmation bias and heuristics to arrive at conclusions.
In conclusion, Zimring summarizes, “We need the availability heuristic, and confirmation bias, and all of the other forms of misperceiving the fraction described herein. They fuel our advances as well as lead to our demise” (p 201). A contradictory statement of sorts alludes to the complexity of trying to decipher something that should be logical and yet is not.
Julie Kinyoun
Julie Kinyoun is an on-call chemistry instructor at various community colleges in Southern California. An avid reader, she enjoys reviewing books that help her become a better educator.
