This book was not on my reading list, but I happened to see it while browsing my library’s ebook shelves and decided to take a chance on it. It was better than I anticipated, a good introduction to critical thinking skills. It starts with a section called Evaluating Numbers and moves from the very basics, such as statistical mean-median-mode to a discussion of chart shenanigans like hiding data and playing with multiple axes. It then abstracts the discussion from specifics to general observations of how data is collected and the questions we should ask about how it is analyzed, aggregated, and described. This leads to a theme that will be repeated throughout the book, that no one should accept assertions at face value. There are many, many ways to mislead, both accidentally and intentionally, and in the internet age entire websites and news organizations exist to manipulate and misrepresent information for political purposes.
One of the chapters in Section One is on probabilities, and has the clearest explanation of Bayes’ Theorem I have come across, complete with some excellent examples, including a horrific one where doctors who did not understand how to distinguish real positive and negative results from false positives and false negatives convinced hundreds of women to undergo major surgery for breast cancer which the vast majority of them never had.
The second section is Evaluating Words, and moves from statistics to psychology and sociology. It looks at what makes someone an expert, and makes a point we should all remember, that a person who is an expert in one area could be out of their depth when speaking about others. The fact that someone has a PhD in one field does not necessarily mean they know what they are talking about when they speak on another, and the author provides several examples to make his point. This section made me think about two such examples which are not in the book: when the NFL was finally forced to study head trauma among current and former players, they showed their contempt for the process by putting in charge not a neurologist or a brain scientist, but a dermatologist. And when the Trump administration wanted plausible-sounding medical advice from a doctor who would say what he was told to say about Covid, they found a pliant radiologist, not a qualified epidemiologist.
The book’s final section is Evaluating the World and is a general discussion of how science works and how to recognize logical fallacies. There are also some good examples of how statistics can get misused in court.
A Field Guide to Lies will make you think about how you think: the things you know, the things that you don’t, the things that you might know but don’t know that you know, and the ones you don’t even know that you don’t know. Among the most dangerous of these, and a kind which plagues modern life and policy discussions, are the things that people believe that aren’t true. As Mark Twain (perhaps) said, “It ain’t what you don’t know that gets you into trouble. It’s what you know for sure that just ain’t so.” Think about QAnon, whose followers fanatically believe in outlandish and ridiculous things and are immune to facts and logic – any attempts to prove them wrong are interpreted as more evidence that they are right. While they may be one particularly toxic and pathetic example, there are plenty of people who get their news from biased and partisan sources, and never consider how they are being manipulated. These include not just your crazy uncle who goes on and on about conspiracies and cabals, but members of Congress, who are setting policy for the country. We all need to do our part to ensure that we understand what we believe, and why, and how we have come to trust the sources that back up our beliefs. These are dangerous times.