Understanding versus Knowing


A truckload of bricks and a stack of lumber may contain everything you need to construct a house, but you will never have a house you can live in until they are all assembled in the right order. In the same vein, a pile of books may contain everything you need to prepare for your USMLE, but you are not ready to take your exam unless the material is organized it a way that makes it useful. Collecting the essential pieces is not enough. You must assemble the pieces in a way that allows you to see the fundamental patterns which are the key to successful problem-solving. Beyond simply having the knowledge, you must make sense of it.

Exams in medical school are often about having the right pieces of knowledge. You are faced with questions that ask you to regurgitate the knowledge you have memorized explicitly for that test. In a sense, medical school exams are a checklist, and the professor simply seeks assurance that you have learned each of the facts that they consider most essential. In medical school, if you have the knowledge, you have the answer.

The USMLE is asking for something different out of you than your medical school exams. Top scores on any USMLE Step depend not on knowing, but on using the knowledge you have learned. USMLE questions ask you to think and apply, not recognize and tell. On the USMLE, application of knowledge is key; when you understand the issues involved, you can more clearly see what makes the best answer.

Fortunately, your USMLE preparation time provides a unique opportunity for the type of reflective overview these types of questions require. Medical school or clinical practice with their pressing daily demands and vast amount of detail do not give you much chance to get this perspective. Details are not only overwhelming, but they can distract you from your real goal of understanding. As someone once said, “When you are up to your ass in alligators, it is difficult to remember that your initial objective was to drain the swamp.”

USMLE preparation is a time to move from collecting the pieces to assembling the puzzle picture that organizes and brings clarity. Remember that your goal at the end of this process is not to simply know things, but to understand how they all fit together. Only from that perspective can you respond to the sort of problems that you will encounter in each exam question. The key to effective study is not the accumulation of individual pieces of knowledge, but grasping the essential patterns that tie together the pieces and give them significance. In short, the core task is not to learn about things, but to learn the relationships among things.

These patterns and core concepts elevate you a higher level of understanding, but they also offer a framework which makes the task of rote memorization easier and more efficient.  Trying to recall individual facts is a difficult, thankless, and ultimately unprofitable task. Understanding how things fit together not only gives you the big picture, but also helps you retain the little details. With the right organization, the general patterns built from what you are able to remember help you figure out what specifics facts you may have forgotten.

So, how do you gain this larger understanding? How do you get attuned to the relationships so you are not blinded by the multitude of facts? Learning relationships occurs by three basic methods: Examples, Metaphors, and Contrasts.

Examples show you concrete instances of the thing under discussion. The abstract issue is grounded in the concrete referent. By the concrete example you come to see context and even how things change over time. Examples let you grasp core principles by inductive reasoning, that is, picking out what are the most essential features that bring things into focus. When I talk about an autoimmune disorder, you hear all of the defining features. But when I describe the process and progression of HIV/AIDS, you have a picture of something specific that anchors your retention of these essential features.

Metaphors highlight essential relationships by carrying over a known relationship to another context. A metaphor focuses on the essential relationship by virtue of the specified comparison; not an example of a thing, but an example of a relationship. To say e coli has a propulsion mechanism is one thing, but to say it propels the pathogen like a propeller on a submarine gives a more vivid picture of the possibilities for mobility. To say one of the signs of Lupus is a red facial rash is correct information, but to say it looks like a butterfly gives a picture of a cluster of essential details which are otherwise difficult to convey verbally.

Contrasts highlight features by comparison. This comparison serves first a positive function, focusing our attention on certain features by virtue of the referent chosen for the contrast. Each thing in the world has a large number of characteristics or properties. Contrasts among things help us to see which characteristics are more worthy of our attention. Secondly, contrasts also help us understand what something is in a negative sense; helping us see what something is by showing us what it is not. Describing Parkinson’s symptoms is one level of understanding. But, comparing the similarities and differences between Parkinson’s symptoms and the symptoms of Tardive Dyskinesia elevates our understanding of both disorders. Contrasts focus us on what is unique and, thus, what is most essential. Trying to recall all the features of an elephant is too hard. But, being able to say how an elephant is different from a hippopotamus clarifies our understanding of the unique features of each animal.

Examples, metaphors and contrast are the key techniques for elevating you from simple rote memorization to systematic understanding. As you do your studies, take time to think about: “What would this look like?” “What else is like this?” and, “How is this different from something else?”

Knowing things is not enough. The most essential insights of medicine are not what things are but how things relate to each other. You build up your USMLE score as you build this understanding of how things fit together. Focus not on the accumulation of facts, but in fitting the facts together in a way that makes sense. Once these relationships are clear, the knowledge will never leave you. And from the building blocks you will have constructed a “house” you can live in for life.

Steven R. Daugherty, Ph.D.