My answer may be surprising. It is not the response given to me by my professors, when they were asked similar questions. I recall them telling me that virtually nothing that I was learning in medical school would be correct 20 years later.
I have thought about this since and will reveal my answer shortly, but before I do, we should pause for a moment to reflect on the process of medical education. I will refer here to natural selection as an analogue of this process, a concept that I have adapted from some ideas gleaned from David Dawkins and Susan Blackmore.
Darwinian natural selection is based on the concept that replicators (eg genes, viruses, prions) compete for their locus based on the phenotype produced. In the case of genes, these replications are done with high fidelity, but not perfectly, so that there are a few imperfect copies (mutations) produced, such that there are alternative genes meant for the same chromosomal locus (alleles). It is the competition among the alternative alleles, measured by their phenotypic expression that is the basis of natural selection. This process accounts for all of the dramatic variation seen in nature, including the present state of the information processing hardware (the brain), but it does not account for more rapidly changing behaviors and beliefs (cultures).
For example, as David Dawkins has observed, women’s right to vote swept across the world as a cultural norm in just about a century (New Zealand in 1893 to Kuwait in 2006), much too fast to be explained on the basis of genetic evolution.
The cultural analogues of genes are memes. If a gene is a bit of nucleic acid that is capable of exactly (and occasionally inexactly) replicating itself, then a meme is a unit of cultural inheritance that can reproduce itself with varying degrees of fidelity.
The analogy to genes is not perfect in that memes have no easily visible structural components, such as chromosomes, but memes are replicators that can compete with alternative versions based on the phenotypic outcome, namely that the meme will successfully reproduce itself. Successful memes can spread rapidly from brain to brain, producing a zeitgeist (spirit of the times), an example of which is the spread of the cultural norm of women’s right to vote, at a rate (only a century) that is much too fast to have occurred by genetic natural selection.
A “successful” meme is one that is more likely to reproduce itself. The word successful in this context has no other higher moral meaning. Memetic evolution cannot be engineered any more than we can engineer genetic evolution, because the conditions upon which the phenotypic competition will depend are not known prospectively. Indeed, those cultural conditions are themselves determined by memetic competition. Like genes, memes do not exist in isolation, but may be influenced by other memes, producing memeplexes. Examples of memeplexes include clubs, universities, professional societies and religions.
Because of their relative youth, changes in medical educational methods cannot have evolved by genetic evolution (i.e. it is very unlikely that the brains of Hippocrates, Maimonides, Charcot and Osler were substantially different from each other or from ours). A partial list of successful memes for medical education might be:
- Doctors are servants of their patients
- Doctors are teachers who pass their knowledge to their successors
- A doctor-patient relationship is private
- Doctors are skeptical scientists who use evidence to apply current knowledge and to devise new methods of diagnosis, disease prevention and treatment
So-called core competencies (medical knowledge, patient-care, professionalism, interpersonal and communication skills, practice-based learning and improvement, and system-based practice) are not memes. This is precisely why they are so counter-intuitive and difficult to apply independently when thinking about a given doctor’s performance. They have not evolved through memetic competition, but rather have been imposed by committees and bureaucrats. Arguing that these competencies are necessary for evaluation because we have done a “bad” or “incomplete” job educating doctors in the past is analogous to arguing that wings are superior to scales. The comparison is absurd. It clearly depends on the environment and the environmental conditions that will determine the success of future memetic mutations is at best questionable and more likely totally unknown. The current medical culture is obsessed with perfect replication and avoidance of error. This stemmed from the 1999 alarmist report of the National Academy of Medicine, entitled “To Err is Human,” in which the absurd conclusion was propagated that more patients died from medical errors than from breast cancer, heart disease and stroke combined; now updated by The National Academy of Medicine’s (formerly the IOM) new white paper on the epidemic of diagnostic error.
For many years now, I have been collecting my own errors and intermittently categorizing them according to various causes of the mistakes, such as misuse of shortcuts or heuristics (eg framing, anchoring, availability, representativeness, blind obedience), premature closure, inadequate knowledge, such as failure to grasp Bayesian principles, or hubris. Some of these ideas were gleaned from the work of Daniel Kahneman and the late Amos Tversky, summarized in Kahneman’s book, Thinking Fast and Slow. With the help of my colleagues, Allan Ropper and Barbara Vickrey, I have made it a habit to present various versions of this errors talk in many settings including the national meetings of our professional societies, various grand rounds venues, resident and student education sessions and as a visiting professor in numerous institutions. The exercise is valuable as a teaching tool as it personalizes the experience of trying to come to grips with complex medical decisions, but there is actually no convincing evidence that studying these mistakes and using various contrivances to focus on them, reduces their frequency whatsoever. For example, there is absolutely no reason to believe that a comprehensive medical record will reduce the frequency of cognitive errors, whereas it is evident that efforts to populate this type of record can remove the doctor’s focus from the patient and place it on the device. Doctors are actually very open to thinking about their mistakes, but one of the worst mistakes is the belief that one can eliminate mistakes.
The process of genetic evolution is not random, though the individual mutations occur by chance. The same may be said of memetic evolution. The evolution of organisms, ideas, religions and customs occur in tiny steps each one of which is the result of competition between a perfect copy of the prior generation and one that is slightly altered. The alteration itself is a random event. So-called “intelligent design” no more works to explain the nuances of culture than it does biological diversity. If a slight change in our way of educating future doctors is a successful meme, it will exactly reproduce itself and the zeitgeist will be altered, just as we see in retrospect about women’s right to vote. If not, it will disappear into a sea of non-improvements, the nature of which we cannot even remember. Our brains have not evolved to design the future. Attempts to make them do so will be futile.
The miracle of the rapid conversion of ordinary people, most with only four years of medical education, into doctors occurs because of a memetic process whereby the doctors in training rapidly copy the clinical method of the generation before them. Thereafter the process of change becomes extremely slow and is fueled only by mutations in the perfect copies (errors). Without these errors, there would be no further evolution of medical thought and we would have the same views of medicine as our forbearers. Note that change does not make us “better” than our professional ancestors; only more adapted to the current environment. My great great great great neurological grandfather, Jean Martin Charcot, would undoubtedly not be able to recognize AIDS, but he could spot a case of tabetic syphilis literally at fifty paces, something that I certainly cannot do. The futile crusade for the eradication of error by ever more perfect guidelines and computer programs will only produce robots, which can only do exactly as they are told.
Therefore my answer to the initial question may no longer surprise you. At least 90% of what I use as a physician today I learned by copying my teachers. The rest has been very gradually altered by innumerable errors, some of which, by chance, changed my thinking or practice, little by little. One may like to imagine that we have made enormous advances over our ancestors, but, alas, this is not the case. Even some of the seemingly enormous changes that have occurred during my career, such as CT and MR imaging and genetic testing, have only slightly altered the clinical method that I now use to try to help real people. Of course, I try the best I can to avoid errors, but there is absolutely no way that I can succeed. Doctors must make myriad mistakes, recognize them for what they are and change gradually as a result of the tiny percentage of them that make one better adapted to the environment, whatever that may be. This process is not controlled by our free will. We all try to avoid errors but none of us will succeed. This is fortunate as errors are the only road to progress. Focusing on the evil of errors takes our attention away from the real enemy, which is illness. We should relax and enjoy the fact that we are lucky enough to be doctors. Future generations can judge what changes were or were not worth making.
Martin Samuels, MD is Chairman of Neurology at Brigham and Women’s Hospital.
Dawkins R. The Selfish Gene
Blackmore, S. The Meme Machine
Kahneman D. Thinking Fast and Slow
Vickrey BG, Samuels MA, Ropper AH. How neurologists think: a cognitive psychology perspective on missed diagnosis. Ann Neurol 2010; 67: 425-433.