I like to be believe that I am a rational thinker who makes rational decisions, particularly when it comes to medicine. However, such rationality tells me that I am surely an irrational thinker, subject to the same list of cognitive biases as anyone else.
We are all familiar with optical illusions which fool our visual pathway into thinking it is seeing one thing, when the reality is actually quite different. Similarly, cognitive biases can be thought of as inherent brain processes which “fool” our abilities to make decisions under various circumstances. While no one is immune from cognitive biases, it has been demonstrated that the ill effects of these biases can be mitigated with education. That is, if we are taught about the various cognitive biases, we are less likely to be affected by them, and many medical schools and residency programs integrate this education into the curriculum.
Despite my interest and (presumably) above-average knowledge about cognitive bias, I know that I am not immune. I have an example. Early in my neurology training I received a consult request from the Emergency Department about an otherwise healthy young woman with vision loss in one eye. In neurology this is a “classic” presentation for optic neuritis. In order to facilitate the work-up for optic neuritis I suggested to the ED to go ahead and order an MRI of the brain and optic nerves, because it would likely take many hours to obtain the MRI and the order would “start the clock”. But when I finally had a chance to examine her, it was instantly clear she did not have optic neuritis, and that the MRI would be normal. On my exam, she described complete 100% vision loss in only one eye, but her pupils were both briskly and equally reactive to light. That is, she did not have an “afferent pupillary defect” which should have accompanied optic neuritis of this severity. In fact, monocular vision loss with an intact pupil can essentially be only one thing, conversion disorder. I performed several other bedside tests, all of which confirmed relatively good vision in the “blind” eye, despite the patient claiming she could not see anything at all. The rest of her neurologic exam was entirely normal.
(click the “2” below to go to the next page in the article)