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How Patients Think, and How They Should

Most of us believe we are rational decision makers. But medical decisions are especially complex, thanks to the numerous unknowns and the uniqueness of each person’s body.

Groopman and Hartzband (in Your Medical Mind) explore two sets of biases that affect patient decisions. We can be minimalists, preferring to do as little as possible, or maximalists who aggressively pursue treatment. We can be technology enthusiasts, seeking the newest drugs or procedures, or naturalists who believe the body can cure itself, perhaps with the aid of spiritual and plant-based remedies.

…When it comes to deciding whether to pursue a certain treatment, the rational course is to consider all the relevant factors — age, weight, medical history, other conditions and so on — and then follow these newly refined statistics, a process known as Bayesian reasoning, a method Groopman discusses in “How Doctors Think.”

Yet studies by cognitive psychologists have shown that our brains are not configured to think statistically, whether the question is how to find the best price on paper towels or whether to have back surgery. In one famous study, Amos Tversky and Daniel Kahneman found that even doctors and statisticians made an astonishing number of inference errors in mock cases; if those cases had been real, many people would have died needlessly. The problem is that our brains overestimate the generalizability of anecdotes. Scientists call anecdotes the “n of 1,” pseudo-experiments with no controls and only one subject. The power of modern scientific method comes from random assignment of treatment conditions; some proportion of people will get better by doing nothing, and without a controlled experiment it is impossible to tell whether that homeopathic thistle tea that helped Aunt Marge is really doing anything.

Your Medical Mind is kind of sequel to Groopman’s 2007 best seller, How Doctors Think.


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