Humans have an ocular blind-spot in each eye. The neurobiologists explain the ocular blind-spot phenomenon by describing how there are no light-sensitive neurons on the retina where the optic nerve exits at the rear of the eye, and therefore no sense data can be processed there. This is actually a pretty good way for describing how a splotch might appear on the screen of your smartphone: an absence of photon-producing pixels.
Even after many years of teaching sensation and perception to college students, I am still surprised to learn that many are reluctant to accept that they have a blind-spot in their visual field. The reason why the visual blind-spot is seldom recognized is that they have never had any reason to perceive it. Indeed, it seems that it is only useful as a gimmick in the general psychology classroom. Far more interesting than the fact of our blind-spot is that the latter is routinely ignored.
If you have ever used a smartphone with a cracked screen, or driven a car with a cracked windshield, you will remember how distracting the crack was initially. You had grown accustomed to a particular interaction between yourself and your smartphone (or car), and now this crack has inserted itself into this routine. Eventually, you learn to navigate the miniature, backlit, rectangular world of search engines, GIFs, and videos despite the visual impediment. The impediment fades away from your awareness, and you eventually stop noticing it.
Sunglasses tint the light in your spectral world only until you have grown accustomed to the tintâthen you might even forget that you are wearing sunglasses at all. You adapt to a new routineâa new way of making sense of the world and of understanding your interactions within it.
These kinds of blind-spots can be understood by the phenomenon of sensory accommodation. This occurs when something is present and available to your perception in a continuous wayâbe it a smell, sound, or tactile sensation. While it is noticed at first, after a while it begins to fade away. A hospital room, for example, might initially smell funny, have a distracting number of whirrs and beeps, and be dimly lit. These are all noticeable at first, but after a while they fade away. It is not that they have disappeared, but you no longer actively discriminate between them in your perception. If, for example, the beeping was to stop, then you would probably notice that something had changed even if you could not quite identify what it was. Sensory blindness due to accommodation occurs when the meaning of the perceptions (such as the funny smell in the hospital room) is insignificant.
Sometimes, however, blind-spots contain information that is very significant: such as those that occur as a consequence of your position within your car and its position on the road. Seated in the driverâs seat, you have an excellent view of the direction you are heading. A sprawling windshield allows you to see nearly everything in front of the car. Three mirrors capture views in the reverseârear, right-rear, and left-rear. Even with these four perspectives combined, there are a few views that are missed entirelyâviews that can be large enough to fit a minivan full of children. Unless you are diligent enough as a driver to look over your shoulder to examine this vehicular blind-spot, there is no way of knowing what is being missed.
Checking blind-spots while driving isnât just a helpful practice, it is essential. To be sure, it is uncommon to be surprised by what you find when you do. But even if you are surprised only once out of 100 (or 1000) times, the practice of checking will have been worth it.
I have described two kinds of blind-spots above. The first can be understood through sensory accommodation, which happens when the meaning of a particular perception proves insignificant. The second has to do with the way a practice or procedure has been designed. The structure, seating, and setup of the contemporary automobile (as well as the infrastructure of the road and highway systems) make vehicular blind-spots a reality. Engineering can go into minimizing the visibility limitations, such as with the development of rear and side-view cameras, but unless roads prohibit any kind of driving that is not single file, there will always be the risk of blind-spot under-sight.
Modern medicine has a blind-spot. Like the vehicular blind-spot, it is enormously significant. Also like the vehicular blind-spot, the medical blind-spot is also a consequence of the way that medicine has been developed. Like side-viewing cameras on automobiles, it wouldnât take an enormous change to notice the medical blind-spot. However, medicine has been practicing with this blind-spot for so long that it has become increasingly difficult to notice what is being left out. It amounts to trying to get college students to discover their visual blind-spot. Some students are eager to see it and understandââhow will I know when I have found it?â While others fold their arms indignantlyââI donât have one; nobody has one; this is ridiculous.â
The medical blind-spot also shares something in common with the blind-spot of sensory accommodation. With the latter, we no longer notice something because it has proven insignificant: we have not had to understand the world by way of this phenomenological detail so it fades away. With the medical blind-spot, a particular way of viewing health, wellness, and the practice of medicine has resulted in ignoring additional aspects of health and wellness.1 Because the latter are systematically ignored, they are understood to be insignificant. Finally, because they are understood to be significant, they have faded from view.
The medical blind-spot misses the existential dimension of human beingâthe structure of meaning through which experiences always unfold. This obviously doesnât happen over the course of a year or even a decade. It takes many decades. The modern iteration of medicine did not begin by neglecting its existential dimension. The latter was merely an effect of viewing the medical subject scientifically. Moreover, the experimental handling of medicine has experienced many decades of improvements (which will be explored further in Chap. 4). As generations of providers were trained within the medical model, with no mention of the existential dimension of health and wellness, it became easy to assume that the latter was insignificant. Indeed, even the language surrounding it has come to seem awkward and unhelpful.
To trace the historical development of the medical blind-spot, I will begin by going back 100 years to World War I, when German neuropsychiatrist Kurt Goldstein was noticing that the medical model had left out an essential ingredient to the understanding of health and wellness. For Goldstein, the blind-spot concerned the meaningful coherence of organic activityâa phenomenon he called self-actualization. Goldstein notices the blind-spot as an effect of the scientific practice of medicine and warns fellow providers not to get stuck within any particular (but limiting) paradigm of medical practice. Next, I will move the clock forward 25 years to World War II, where a Swiss psychiatrist, MĂ©dard Boss, was realizing that something was being left out of modern medical practice. By then, the problem was becoming more and more difficult to articulate. At a loss for words, Boss consults with German existential phenomenological philosopher Martin Heidegger, eventually asking him to come to his clinic to teach the other resident physicians.
Kurt Goldstein Identifies a Crisis in Medicine
As a German neuropsychiatrist during World War I, Kurt Goldstein was assigned to work with soldiers who had suffered closed-head injuries. In the early part of the twentieth century, neuropsychology and psychiatry had not yet been established the way that they are today. Indeed, the first neuropsychiatric department of a hospital was not developed in the United States until the 1920s at Harvard, under the direction of Karl Lashley. The lack of research into and protocol for handling closed-head injuries made the work of neuropsychiatrists during World War I exceedingly important, and few would become more influential than Goldstein.2
When applied to closed-head injuries, the model of modern medicine suggests that deficits in behavior or cognition could be explained by deficits in the brain, even when the brain could not be seen directly. If a soldier is admitted with paralysis of his right arm, then it could be concluded that the âright-arm-areaâ of the primary motor cortex had been damaged. At the time, this method was called associationism (but it is now called the identity hypothesis). Associationism is the assumption that discrete brain regions are responsible for discrete cognitive and behavioral functions. If the âright-arm-areaâ of my brain is damaged, then I cannot rehabilitate right-hand activities and must instead learn to go about my duties without it. If, however, I had merely torn a rotator cuff, then I could be prescribed a series of stretching and strengthening practices in order to rehabilitate full right-arm mobility.
Goldsteinâs assignment was to determine who was injured and who was malingering. Of those who were injured, he was to determine who could be rehabilitated (to return to battle) and who must be discharged. To do so, his task was to identify the presenting symptoms and trace these to the nervous system in order to determine what neurological damage had been done. Hereâs how it should have gone: (1) identify the behavioral deficits (deficit a, deficit b, etc.); (2) determine the locus of the deficits (locus a, locus b, etc.); (3) prescribe rehabilitation plan, if any.
This presents an easy-to-follow guide for understanding the newly emerging field of neuropsychiatry. It follows exactly the steps of any other diagnostic-prognostic strategy in modern medicine, whether one has found a broken leg or lung infection. Record the symptoms; identify the underlying cause of the symptoms; focus treatment on the underlying cause. This is what you attempt to do when you search for your symptoms on WebMD or Wikipedia. You compare the symptoms associated with a whole bunch of discovered diseases and compare them to your own, then follow the recommended courses of treatment.
When trying to follow this 1-2-3 method, Goldstein quickly found that there was an impossible feature in the first step. The first step, you will recall, deals with the determination of symptoms. Evidently, there are many problems that accompany this step. The title of Section I, Chapter 1 of The Organism captures this: âThe Problem of the Determination of Symptoms.â In this section, chapter, and throughout the book, Goldstein lists many problems with the symptom focus, beginning with how to determine which symptom is the important one. One problem with the symptom-determination approach that Goldstein observes is that a symptom can never be isolated to one aspect of the patientâs behavior. For example, a tear in the plantar fascia is not only evident when the fascia must contract but may be seen in the global modification of the patientâs behaviorâlike a reluctance to put weight on that leg, or a ref...