Ellie asked me to write a post about something called Environmental Mismatch (from here on, just EM). I studied this concept as part of my PhD program (not done yet, thanks for asking) in anthropology at UConn, and it is a simple but powerful idea that has helped both of us understand some of the challenges many people face in the modern world.
Put simply, EM is what happens when an organism finds itself in an environment that doesn’t match the conditions in which it evolved. For example, some fish have evolved to breathe fresh water. If you put one of those fish in salt water, it will suffer and probably die, because it is in an environment so different from the one it is built to live in. In humans, this concept plays out similarly, though most examples I will describe in this post don’t lead to death (though some could, if not treated appropriately).
One example of EM for people is jet-lag. The human body and brain are calibrated to work on a roughly 24 hour cycle, and changes in the timing and amount of daylight we experience take place gradually over weeks and months. If we walk two thousand miles, our bodies have plenty of time to adjust slowly to any change in time zones. However, if we fly two thousand miles in a couple of hours, our bodies are still expecting to experience the same timing of light and dark as usual, but when they encounter a sudden change, it throws off our circadian rhythms for several days until we adjust to the new normal. Our hormone systems simply didn’t evolve to handle such rapid changes in location, but because our technology allows us to travel so quickly, we experience the fallout of environmental mismatch.
One thing to keep in mind is that EM is NOT always a bad thing – it can cause problems, sure, but it can also create important opportunities. Here are just a few other examples to think about:
- Humans evolved in small groups, in which individuals typically knew most of the people they would encounter on a regular basis. Today, many of us interact with strangers every day. This creates the opening for much greater understanding across cultures, but also challenges innate notions of groups, and can create stress. (Ellie jumps in here) Picture your first day of high school looking around the lunchroom and trying to find the familiar faces you already knew.
- Humans evolved in environments in which sugar and fat sources (types of food) were patchy and not reliable, so we developed strong impulses to both consume and store large amounts of those substances when found. Fat and sugar are everywhere today, but our paleolithic bodies and desires still crave way more of them than is healthy.
- Our best guess from studying foragers across the globe is that we evolved in settings in which much LESS time was spent “working.” In a foraging environment, work might mean finding, processing, and preparing food, or perhaps creating tools or dwellings. On average, this way of living leads to about a 20-24 hour work week. Compared to the number of hours most of us spend working (not to mention the additional hours spent on child care, shopping and cooking, commuting, etc), our modern lifestyle is far more stressful and less leisurely. The cost of those high levels of stress (measured by cortisol in the brain) can be severe.
- Cortisol response is actually another example of EM. Cortisol is a hormone released in the brain during a time of high anxiety or fear, and it helps prepare the body for a “fight or flight” response. This is a very adaptive thing our bodies can do that can help us survive moments of danger. It is meant to happen occasionally, though, and cortisol is designed to return to normal levels quickly. When we face chronic stress, the effect of constant cortisol in the brain is detrimental, and can lead to decreases in our ability to solve problems, relate to others, major depression and other emotional/mental issues.
I’m not painting a particularly happy picture of modern life here, I know. As I said above, EM does create opportunities, too, but it is important for us to understand the constraints our own bodies place on us, so that we can make decisions about how to react to the pressures of our lives today. One thing I know you’ll find in this blog are lots of ideas that are consistent with the signals our bodies send us about what they need – connecting with loved ones, engaging in regular movement, and considering health and wellness often.