Hiding in Plain Sight: Essays by Joon Yun, MD

Hiding In Plain Sight is a collection of essays that I have written on investing, healthcare, and life.

A Little Experiment

For the sake of experiment, read the next sentence once, while counting the number of “f”s that you see.

“Five-winged flies are the result of years of scientific study combined with the experience of many years.”

Most likely, you counted an “f” in each of the more vibrant words of the sentence: “five,” “flies” and “scientific.” Most people only see these three “f”s, when in fact there are six. The other “f”s are hidden in the unassuming preposition “of”. Your mind probably skipped over each “of” because it processed these words without absorbing the raw information of the letters that composed them.
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Day 222: Joon Yun

(From The Get Inspired! Project)

I go about my day really not thinking about ‘Do I know what I want?’ It’s more about ‘Am I available to what’s going on in the moment?’ And it’s a very nonlinear path, but it is much more … because I’m vulnerable and I don’t know where we’re going, I’m much more aware, and I find solutions to questions I wasn’t even asking.”

Toni Reece: Thank you so much, Joon, for agreeing to be part of the Project today, and before we begin, can you please introduce yourself?

Joon Yun: Yes, my name is Joon Yun. I am President of Palo Alto Investors, an investment management firm located in California, and I’m a physician by background. I ran healthcare investing at a firm for about 10 years, and I’ve been overseeing the firm for the last 2 years.
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Three Secrets to a Funnier You

Why Teach Humor?

“The most wasted of all days is one without laughter,” said the poet E.E. Cummings. Those who trigger our laughter with their humor are the people we want to spend time with, work with, or date. Humor opens our eyes to unexpected possibilities in the world, relieves our stress, improves our health, ameliorates an awkward situation, and increases our influence on others. It is widely assumed that people who are funny were born that way and so the development of a sense of humor and an ability to be humorous is left largely to the luck of the draw — your family circumstances or the television shows you watch.

Those of us who grew up in a mainstream educational system were taught reading, writing, and arithmetic in school. Anyone cracking jokes in the back of the room was fined with twenty-thirty minutes in a minimum-security afterschool detention center. Now, we know that the humor that institutions failed to appreciate when we were children can help us tremendously in professional, romantic, and social settings. So, what can we learn from the kid in the back of the room? What if we approach to humor as a skill that carries as much weight in our daily lives as reading, writing, and arithmetic? Certainly more than algebra!
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Compound Thinking


Children are trained to count linearly: one, two, three, four, five, etc. Long before mathematics was invented, however, a subjective process of estimation was used to quantify and make decisions. If the ability to appreciate quantities in linear terms confers fitness advantage, that edge appears to have eluded Darwinian selection. Studies of the Amazonian Mundurucu indigenous tribe and preschool American children all suggest that humans are innately wired to use a compressed scale to understand magnitude – not unlike those depicted by logarithmic, exponential, or power-law functions. A compressed scale is biased toward achieving higher resolution at the lower end of the spectrum where smaller numbers reside, where discriminating subtleties in degrees of scarcity can provide the greatest benefit. Psychophysical studies assessing the magnitude of subjective estimation of sensory inputs such as light intensity and sound intensity also reveal innate mapping of signals on compressed scales. From an adaptive perspective, a compressed scale of subjective estimation enables a wider dynamic range of sensory processing which is valuable in environmental signal interpretation. The hypothesis that selective pressures favored the cognitive adoption of a compressed scale for subjective estimation is consistent with the reality that natural phenomena generally unfold through iteration, yielding patterns of development that are best understood through the prism of compounding rather than the lens of linearity. Like an intellectual slide rule, modern mathematics reprograms children. It obligates them to abandon their natural cognitive tendencies, which rely on compressed scales and estimation and coerces them into adopting linear scales that provide uniform resolution along the entire scale. It resigns them to participate in a wholesale exercise of indiscriminate precision with respect to all things. This force-fed mental framework may help individuals thrive in the artificiality of our modern socio-cultural-economic landscape, replete with man-made straight lines and standardized tests. However, we believe that the conflict between our innate instinct to estimate on a compressed scale and our learned ability to quantify on a linear scale is a source of profound decision dysfunction in the modern world, particularly impairing the ability to assess the possibilities of outlier outcomes.
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Darwin in Medical School

Some scientists call for a bigger dose of evolution in doctors’ educations


Joon Yun, MD, began considering how evolution applies to human health a decade ago when his first heart disease patients died. These cases disturbed Yun, then a Stanford radiology resident. But they also intrigued him.

Having studied evolutionary biology in college, Yun tried fitting these medical failures into that framework.

His mind wandered to the early days of humans when heart disease was a rare trigger of death. In the prehistoric era, a more likely cause of death would have been an attack by a predator. The human body’s response to trauma handles this type of assault by immediately springing to action: The blood forms clots and the blood vessels tighten, together with slowing blood loss, and inflammation kicks in to combat infection. The genes governing these responses to trauma presumably were favored during evolution and have become the “factory setting” in modern humans.
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