Natural Evolution is Slower Than Cultural Evolution

I’ve argued elsewhere that the human brain no longer is well adapted to the modern world that we’ve invented – a world vastly different than the one in which natural evolution crafted our brains. The reason that our physical brains lag behind is that our culture evolves faster than our genes: Natural evolution is a slower process than cultural evolution.

By cultural evolution, I mean the changes in our ideas, our technology, our inventions, and our society as a whole. This kind of evolution can proceed relatively quickly, because ideas can emerge over short periods of time (minutes, months, days, or years) and be transferred between people easily. Think about how remarkable it is that in the span of only a few years, our culture has seen the first black president and an increasing acceptance of homosexual marriage – two important steps in our moral development, and at the same time amazing cell phone and internet technology have significantly changed how we live our lives.

On the other hand, the genetics of our species change at a much slower rate. So slowly, in fact, that there are likely few physical differences between our brains and those of our 50,000 year old behaviorally-similar ancestors. There just hasn’t been enough time – evolution often acts over hundreds of thousands of years, and many of the most striking changes in our culture have happened in the last century or two. So, the result is that our brain and our bodies have outdated features that no longer make sense in the modern world.

A striking example is the obesity epidemic in many first-world countries. What is its cause? Our taste for high-caloric food combined with modern lifestyles without manual labor. Despite appearances and pundits, the underlying issue isn’t lack of self-control or laziness – it’s a fundamental disconnect between modern life and the desires of our cave-man body. In other words, fatty sugary foods need not taste good – it is not a fact of nature, but a fact of our own biology. Our bodies evolved in a time when food was hard to come by and rigorous physical activity was unavoidable, so it made sense to stockpile energy and to desire energy-rich foods. Because these desires makes zero sense in first-world countries, we have to do strange things: We must apply self-control to diet and unnaturally limit our dessert portions, and try to trick our bodies into producing more muscle by going to exertion simulators (also called gyms).

There are many other examples as well – like women’s attraction to physically strong men, or men’s attraction to waist to hip ratios that might at one time have indicated fertility. But in a modern world where physical strength is largely irrelevant, and science allows nearly all women the ability to bear children successfully, this conception of attraction makes little sense. It’s not a fact of nature, but just how our brains evolved, because in our evolutionary past, those signs were potent predictors of how promising a mate was. But it’s hard for us to imagine being attracted to things other than those we’re attracted to.

The important point is that we often take for granted that the way we experience things is both the only possibility and inherently good or right. Of course this isn’t the case – with different biology I could find carrots more delicious than bacon, or a woman’s personality and intellect entirely driving attraction instead of superficial appearance. The lesson is that there are features of our biology that simply don’t make sense in the modern world, and that through seeing those features clearly we can broaden our understanding of ourselves and of reality.


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