Truth 16. You may see only what you’re looking for

In his examination of how physicians think, physician and author Jerome Groopman notes that most physicians come up with two or three possible diagnoses within minutes of meeting a patient.⁹ These decisions are influenced by the patients who came before, something known as an availability bias. We tend to try to fit the current situation to other examples readily available from our own experience.

For example, Groopman tells the story of a doctor on a Navajo reservation in Arizona who had seen dozens of patients over a three-week period suffering from viral pneumonia. So when a woman in her sixties complained that she was having trouble breathing, he determined that she had subclinical pneumonia. He made the diagnosis even though some of her symptoms and test results didn’t fit this diagnosis (no signs of pneumonia on X-rays or elevated white blood counts). He ignored the facts.