Thursday, March 27, 2008

Mental Models From Guns, Germs, And Steel

I was flipping through Guns, Germs, and Steel by Jared Diamond today. As luck would have it, the first page I flipped to reminded me of not one, but two mental models from other subjects. Maybe these just happened to stand out because I have been reading so much on Charlie Munger lately. Regardless, I kept reading and kept making more and more connections from a variety of disciplines. Here was what I came up with it.


All other things being equal, people seek to maximize their return of calories, protein, or other specific food categories by foraging in a way that yields the most return with the greatest certainty in the least time for the least effort. Simultaneously, they seek to minimize their risk of starving: moderate but reliable returns are preferable to a fluctuating lifestyle with a high time-averaged rate of return but a substantial likelihood of starving to death. One suggested function of the first gardens nearly 11,000 years ago was to provide a reliable reserve larder as insurance in case wild food supplies failed.
The first part of this involves the opportunity cost concept from economics. Here, it is being used in a narrowed sense to describe the satisfaction of hunger. Even more interesting is the idea that people prefer "moderate but reliable returns" of food compared to higher risk and higher returns. You often hear Warren Buffett and Prem Watsa take the opposite statement on investing- that they prefer lumpy but out-sized returns over reliability. On closer analysis, this difference makes sense. In investing, we have a much longer time horizon and so a short-term slump can be handled without severe consequences. But with food, the consequence of a slump is starvation and death- a much less manageable risk.

As we already noted, the first farmers on each continent could not have chosen farming consciously, because there were no other nearby farmers for them to observe. However, once food production had arisen in one part of a continent, neighboring hunter-gatherers could see the result and make conscious decisions. In some cases the hunter-gatherers adpoted the neighboring system of food production virtually as a complete package; in others they chose only certain elements of it; and in still others they rejected food production entirely and remained hunter-gatherers.
This reminded me of my philosophy class on Descartes. He argued that all of our ideas came from a combination of other ideas we have experienced in the past, and no idea could exist in us unless it had some truth in the outside world. The same concept is being used here regarding agriculture. Its mass implementation occurred only after someone stumbled upon farming's great benefits and other people witnessed it.

A fourth factor was the two-way link between the rise in human population density and the rise in food production. In all parts of the world where adequate evidence is available, archaeologists find evidence of rising densities associated with the appearance of food production. Which was the cause and which the result? This is a long-debated chicken-or-egg problem: did a rise in human population density force people to turn to food production, or did food production permit a rise in human population density?
The old Chicken-or-egg dilemma. Just because you have found a correlation between two variables doesn't mean you've also answered which one has caused the other. These are usually two different problems.

That is, the adoption of food production exemplifies what is termed an autocatalytic process- one that catalyzes itself in a positive feedback cycle, going faster and faster once it has started.
We saw another example of an autocatalytic process with the housing bubble. As lenders began to loosen their standards, less people defaulted because they had more access to refinancing. This made the lender's business look great, and caused them to loosen their standards even more.

Instead of being enclosed in a poppable pod, wild wheat and barley seeds grow at the top of a stalk that spontaneously shatters, dropping the seeds to the ground where they can germinate. A single-gene mutation prevents the stalks from shattering. In the wild that mutation would be lethal to the plant, since the seeds would remain suspended in the air, unable to germinate and take root. But those mutant seeds would have been the ones waiting conveniently on the stalk to be harvested and brought home by humans. When humans then planted those harvested mutant seeds, any mutant seeds among the progeny again became available to the farmers to harvest and sow, while normal seeds among the progeny fell to the ground and became unavailable. Thus, human farmers reversed the direction of natural selection by 180 degrees: the formerly successful gene suddenly became lethal, and the lethal mutant became successful.
This is just to remind us of the inherent randomness of the world. Sometimes, you can have every conceivable thing in your favor, and then one black-swan type event comes in and completely changes everything. Long Term Capital Management thought they had a sure thing, and then one "six sigma event" came along and completely wiped them out, endangering the entire financial system in the process.

The second type of change was even less visible to ancient hikers. For annual plants growing in an area with a very unpredictable climate, it could be lethal if all the seeds sprouted quickly and simultaneously. Were that to happen, the seedlings might all be killed by a single drought or frost, leaving no seeds to propagate the species. Hence, many annual plants have evolved to hedge their bets by means of germination inhibitors, which make seeds initially dormant and spread out their germination over several years. In that way, even if most seedlings are killed by a bout of bad weather, some seeds will be left to germinate later.
Instead of seedlings being all killed by a single frost, think of an entire investment portfolio getting wiped out by the loss of a single holding. So what do you do? You hedge your bets. The plants spread out their germination over several years so some seeds will still be left. Similarly, people diversify their portfolio so no single event can wipe them completely out.

I came across all of this within 13 pages, and I've learned two things. One, these big concepts can be applied in a lot of instances if you really look for it. Two, Jared Diamond has a brilliant multi-disciplined mind and I need to really finish his book.

P.S. Many of you might also find this post comparing Bruce Lee's philosophy with Warren Buffett interesting.

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