We are all epidemiologists now. But we have lost an appreciation for the personal, intimate knowledge acquired from our own experiences. Our decisions are increasingly guided by expert recommendations and scientific data, with less reliance on local conditions and individual experience.
We now know what a coronavirus is and how it spreads. We have all tracked changes in prevalence and mortality rates, or, perhaps, we have become inured to them. And we know the length of a coronavirus (measured in nanometers) and whether that paisley bandana allows the virus to pass through. And then there’s the average age of people who die from Covid-19, as well as the statistical likelihood of death given a relevant comorbidity.
In our efforts to learn more about Covid-19 and limit its transmission, however, we ignore local knowledge. This is the kind of knowledge where we make plans to obtain a goal and continually, marginally adjust those plans. Only individuals can access this knowledge, e.g., whether you prefer apples to oranges, your normal activities and behaviors, what your goals are for the day and your life aspirations; who your close friends and family are, where you can buy a cheaper lunch, which café has nicer chairs, etc.
Both scientific and local knowledge influence the choices we make every day—even choices related to health and how we spread infectious diseases.
Scientific and Local Knowledge Complement Each Other
Scientific and local knowledge are useful in many ways but particularly because they can identify causal mechanisms that enable individuals to improve some aspect of their life. Whether it is scientific or local knowledge, individuals strive to acquire relevant knowledge — where individuals define what is and what is not relevant — to better pursue their plans.
Dan Klein makes a related point that when individuals make decisions they actively seek relevant information: “In small simple social settings including the family, club, church, or shop, the decision maker is usually the one most motivated to ensure that her decisions will have the results intended, and consequently she is most motivated either to know herself what course of action will best serve her intentions or to search out and appoint an agent with such knowledge.” The discerning, choosing individual is the key part here.
Imagine that we wanted to lessen anxiety and depression, and you learned that drinking moderate amounts of alcohol might be an appropriate scientific prescription. With just that knowledge however, it is unclear how any one person will subsequently act. Should we start subsidizing alcohol consumption? That would probably lead to some unpalatable and unintended consequences.
As an individual, however, you might start logging more hours at your local brewery if you really liked their new raspberry wheat beer. Alternatively, beer might be harder to find in places with fewer bars, so you might try to find substitutes. Of course, you might not even like beer so you might try your hand at bourbon. The context of your situation, your plans, and your knowledge influences what is appropriate. For example, you will have a tougher time getting bourbon if you live in a state that maintains a monopoly over the sale of alcohol. For people who live under state-run alcohol monopolies, they might resort to enlisting friends in other, more economically liberal states to do some shopping.
Still, there is a complementarity between scientific and local knowledge. The science about moderate alcohol consumption is of limited use in some cases; at the same time, science informs a person’s decision so they can pursue their goals as they see fit.
Joel Mokyr and Rebecca Stein (here and here) show a part of this logic in their work on the changing norms of hygiene and mortality rates during the latter part of the 19th century. As the germ theory of disease developed, people began to understand more and more about infectious diseases and germs and, more importantly, how their own choices influenced health. How individuals went about making use of that scientific knowledge depended on their own circumstances. Many people, women in particular, began to clean more; others improved the quality of baby food; others improved their diet.
All of these choices helped to improve private and public health outcomes in the late 19th and early 20th centuries, but they were choices informed by local and scientific knowledge.
Covid-19 and Knowledge
The complementarity between scientific and local knowledge even matters for our private and public responses to Covid-19.
Scientists, epidemiologists, and public health scholars often produce important work identifying causal mechanisms regarding the spread of infectious diseases, especially under predetermined conditions. That scientific knowledge is necessarily of limited use, however, when individuals alter those predetermined conditions and especially when individuals make choices based on their local knowledge.
For example, suppose you live with someone who is immunocompromised. In this situation it would make sense for you to skip the gym, limit grocery visits, etc., because you recognize the risk contracting Covid-19 would have on your roommate’s health. On the other hand, if you are a healthy young person who lives alone, it would make less sense for you to drastically alter your lifestyle in order to avoid a virus.
That people have plans and make choices based on expected costs and benefits as they perceive them are extremely undervalued notions, but they are essential to understand why and how people respond to changing circumstances and to changing prevalence and mortality rates. Allison Schrager and Jessica Hullman recognize the importance of individual choices when they advocate for improvements in how prevalence and mortality data are presented. To the extent such data convey objective measures of risk, they should be intelligible measures of risk.
Furthermore, Charles Kenny argues that people engage in various kinds of preventative behavior in response to Covid-19, among other diseases. Such responses occur because it is human nature to choose and to alter behavior in response to incentives — even when prevalence and mortality rates change — not necessarily because government officials say so. Importantly, how people alter their behaviors in response to infectious diseases depends on local knowledge.
Jenin Younes also recognizes how local knowledge influences behavior: “…epidemiologists are no better equipped to weigh the competing values that inform how one chooses to live during the coronavirus era than individuals are to make their own choices.” And so does Roger Koppl: “The knowledge we need in normal times and crisis times alike is distributed. It’s out there in thee and me and in all our habits practices and experience. It is not a set of instructions and doctrines coming from on high. It arises of its own from our many decentralized interactions.”
Such approaches to knowledge ultimately suggest caution about what we imagine science alone can help us achieve.
Going Forward with Science and Local Knowledge
Will sweeping restaurant and school closures save lives? Are country-wide mask mandates effective? Do large gatherings of people cause super spreader events? The science and evidence is still developing (here, here, here). Regarding super spreader events, for example, we can easily observe these mass gatherings, imagine how diseases could spread, and then empirically assess the magnitude of such events (here and here), but we should also imagine how people might alter their preventative behaviors given local knowledge.
The kind of information people acquire in their myriad interactions with others is often undervalued as a means of preventative behavior. As helpful as science is for understanding causal mechanisms — and it is — it should not be the only source of knowledge that informs your behavior, let alone policy.