Is Rationality Overrated? What an 18th Century Medical Mystery Can Tell Us About the Power of Blind Copying

By the 1730s a new type of disease was starting to pop up across Europe. Sufferers would lose their hair, develop lesions all over their body, lose their mental faculties and eventually die.

The disease seemed to be linked to corn consumption. Corn was a new crop imported from the Americas only two centuries earlier. Corn is a nutritious, high-calorie crop, and in the intervening two hundred years some regions were already starting to use corn as their main food supply.

Authorities believed the source of the problem to be spoiled corn. Prohibitions on the sale of bad corn were enacted and new laws were created to prevent its consumption. Unfortunately, this did little to stop the disease.

Despite these problems in Europe, Native Americans had been eating corn for thousands of years without contracting the disease. The solution? Mix a little ash from the fire into your corn and soak it before eating.

The disease, which we now know to be pellagra, is caused by a niacin deficiency. Corn does contain niacin, but it is chemically bound and unavailable through digestion. A little alkaline solution, in the form of ash, will free the niacin and prevent the debilitating effects of a nutritional deficiency.

Europeans never thought to copy the Native Americans. Instead, they developed a incorrect causal understanding of the disease and many suffered and died.

A Culture of Reasonableness

The above story was recounted in Joseph Henrich’s book, The Secret of Our Success, which argues that cultural learning, in particular by copying seemingly useless steps, is one of the great intellectual advantages of our species.

Note that the Native Americans themselves weren’t aware of the niacin-unlocking properties of the ash. Speaking with the Machupe in southern Chile, Henrich asked what the reason was for putting ash in the corn. “It’s our custom,” was the only response offered.

Henrich, a trained anthropologist, notes that such responses are common in tribal cultures. In contrast, he argues, “educated Westerners are trained their entire lives to think that behaviors must be underpinned by explicable and declarable reasons, so we are more likely to have them at the ready and feel more obligated to supply ‘good’ reasons upon request.”

Note that the reasons need not actually be correct, they simply must seem reasonable. Pellagra isn’t an infectious disease. But the idea that it is caused by moldy corn is more reasonable than insufficiently following the ritual steps of more experienced agriculturalists.

This finding meshes with what Seligman, Weller, Puett and Simon argue is a modern shift toward sincerity in our belief systems. Sincerity is the idea that our beliefs and practices should be underpinned by good reasons. Science is a natural by-product of the pursuit for sincerity, but so is fundamentalist Christianity. The former seeks to pin reasons in terms of natural laws and experimental evidence. The latter pins reasons in scripture. Both are attempts to give better reasons for our beliefs and behavior.

Useful Superstitions

Pellagra is only one example of seemingly useless traditions having surprising benefits. Henrich also suggests that many hunting superstitions, such as determining the next place to hunt based on the cracks in caribou bones or bird calls, have complex game theoretical justifications.

We’re predisposed to seek and create patterns. Coming up with genuinely random patterns of behavior is very difficult. However there are many situations in game theory where randomness can be a virtue. If your prey animals know that you will tend to return to the same spot, or avoid returning to the same spot, after a hunt, they will use this knowledge to try to escape you. The most effective strategy, therefore, is to randomize your behavior so your opponent can’t predict your next move.

Superstitious rituals can serve as that randomizing element. Of course, the stated reasons for such rituals (if there are any) are unlikely to be complex discussions of game theory. But the outcome is the same—on the long-run, an essentially random ritual, will outperform more reasonable, patterned responses.

When is Innovation Overrated?

Corn ash and caribou bones are not exactly reasons to abandon science and rationality. But I do think they suggest an alternative method of finding useful beliefs and behaviors to the more culturally accepted practice of developing a causal model and having good reasons.

In particular, I think we could expect such ritual-copying to be more advantageous when:

1. The available causal models for a situation have weak explanatory power.
2. The situation is too complex to easily break down why something might work.
3. There is a history of success associated with the practice.

One area I could imagine this playing out is nutrition. Nutrition is still an area poorly understood (1)—only decades ago we were told fat intake needed to be reduced, which many now believe is part of the cause of the obesity epidemic today. Nutrition is horribly complex, so guessing the correct diet from first principles is unlikely (2). Finally, we do have records of other cultures with much better health outcomes, a history of dietary success (3).

Using this knowledge, I don’t think it would be unreasonable to pick a successful culture (say French cuisine or the Okinawans) and try to emulate as much of their culture of eating as possible. Such a step may require a stay in that country to observe not only the what to eat, but when, how and how much, but it seems a more likely successful strategy to me than opting into a newer fad diet.

Another area I could see benefiting from copying without understanding is career success. Often the variables which dictate career success are causally opaque. In that case, simply researching what successful people did and copying them, might be more useful than attempting a more innovative approach.

I take a similar tack with learning new things. Although I have spent a lot of time trying to understand the science of learning, my first step when learning a subject I’m not experienced with is to see what successful learners do. With languages, that was immersion. With math, that was problem sets.

When Should You Be More Reasonable?

The advantage of reasons is that they are flexible. When you know the underlying principles, you can extend them to new situations, discarding the ineffective parts and enhancing the parts that do work. The hidden power of traditions and rituals isn’t to deny the power of science, or be fatalistic about the progress of knowledge.

Copying without understanding is simply an additional tool to deal with the practical realities of life. Sometimes we need to take actions where good reasons are either hard to find, or fail to account for complexity. In these situations, copying from success can be a better strategy than trying to analyze.