The human body is not perfect, having made too many adjustments during evolution
The human body is not perfect, explains American scientist Nathan Lents and author of ‘Human Errors’. We have too many bones, too large sinuses and our eyes not designed for indoors, says Lents (41)
In his book Human Errors, Nathan H Lents writes about design flaws and how they have harmed our bodies. The American scientist holds that our nasal sinuses could have been smaller or even non-existent, which would have been helpful during the COVID-19 pandemic. Lents (41) in fact survived a severe bout of COVID-19 and wrote about his struggle with the disease. He is currently engaged in writing his third book on human sexuality. Edited excepts of an interview he gave Ashlin Mathew.
Why do you think our human bodies are flawed?
Living beings are never perfectly built or perfectly adapted. In fact, there is no such thing as “perfection” in nature. Evolution is a constant struggle and adaptation is about trade-offs, compromises and sloppy solutions to difficult challenges.
However, there is good reason to believe that humans harbour more serious shortcomings than most other animals. I’m not just talking about limits – everything has limits – but actually errors, glitches, quirks, whatever you want to call them. This is because, over the past 10 million years, our ancestors have been gradually transitioning to cultural modes of adaptation, rather than biological ones.
We’ve been using our powerful brains and our intricate social relationships to solve challenges, rather than our bodies. For example, as human ancestors migrated from one climate to another, instead of mutations and selection driving their bodies to adapt to the new conditions, as any other animal would do, our ancestors built shelters, wore clothing, and so on.
This mode of adaptation can be achieved in a generation or two, rather than waiting for thousands of years for mutation and biological adaptation. However, there is a long-term drawback to all this cultural evolution. With the survival pressures taken off our bodies, they were allowed to accumulate flaws and glitches at a higher rate because we simply worked around those flaws with our brains and each other.
Since the design of the human body is flawed you say, what would you change, given a choice?
Fixing the flaws is not as easy as it may sound because our bodies have evolved around these glitches and with everything so interconnected, any change often leads to unintended consequences. That said, I can think of two small tweaks that I think would be very positive for us. First, I would redesign the nasal sinuses to make them much smaller, or even non-existent. We don’t really need them and all they do is create an environment for viruses and bacteria to invade and infect our respiratory system, a particularly harmful glitch as the COVID-19 pandemic rages around the globe.
A second flaw that I think is worth fixing is the way that we absorb vitamin B12. There are bacteria in our large intestine that make this important vitamin, but we are not able to absorb it there. For some reason, we are only able to absorb vitamin B12 in our small intestines, which means we must get it from our diet. If we could absorb it in our large intestine, we could simply take what the bacteria make for us. This would make it easier to be a vegan.
As a woman, I would want to know if while creating a better human body, you would think that her- maphroditism in humans would be a better design?
Almost certainly not. While hermaphroditism has some advantages, there is a reason that most lineages of complex and successful animals and plants have evolved away from this strategy.
You mention that now most of us cannot live with- out spectacles and that 20/20 vision is a myth, especially when we consider the shape of Asian eyes...would you elaborate what you meant?
Well, first of all, there is a world of difference between blindness and somewhat poor vision. And secondly, this underscores the value of cultural evolution and social cooperation. While excellent vision is necessary or helpful for some jobs, it’s not very important for others. The genius of division of labour means that we can all contribute in a way that we’re good at. But more importantly, we now know that poor distance vision is actually a recent side effect of modern living.
Currently, our children spend most of their time indoors, whether at home or in school, focusing on objects very close to them, rather than outdoors focusing on objects at a much greater distance. Accordingly, the growth of their eyes doesn’t occur as it normally would and should.
The developmental programme operates with the assumption that human beings are outdoor people in nature and spend- ing most of their time gazing at things far off in the distance, while also focusing on items in close and intermediate proximity as well.
Countries in which children spend a great- er portion of their time outdoors see much lower rates of myopia.
When we create a design, shouldn’t we allow for design trade-offs, which is necessary in system engineering? Won’t that explain most of what you call flaws?
Yes, this accounts for quite a bit of human You also maintain that being an omnivore is a problem... is that not also a part of our evolution? The switch from herbivore to omnivore was one of the most important transitions in our history! An early step in our path toward a brains-over-brawn approach to survival was what we call foraging. This is when we began to walk upright, but still small-brained ancestors began to expand their dietary palate and explore any and all food sources in their environment.
From hidden roots that had to be dug up to bone marrow that could only be accessed by the cracking of long hard bones, the foods that foragers eat are varied and often concealed. This set the evolution of our cognitive powers in motion because to be a good forager, you need to be clever, have a good memory, and be able to learn from others.
What are the flaws of the brain, especially our memories?
We know very well that our memories are definitely NOT a perfectly accurate record of what we observe. They can be revised, edited, deleted, switched, or even completely fabricat- ed – all without our knowing! (The field of criminal justice has been very stubborn in admitting that eye-witness testimony is not as reliable as we wish it were.)
While this is frustrating, it is also very understandable from a scientific point of view. Our memories evolved to help us survive and thrive, which means they are attuned to more accurately capture some information while ignoring other. Unfortunately, our modern world is very different from the world in which are memories took shape.
While we have invented recording devices that truly capture an accurate record of the past, we have yet to come anywhere close to designing some- thing as powerful as the human brain.
How do you think the knowledge of the flaws in our system, is going to help us?
By understanding our bodies, cells, and genes as fully as possible, we can live in better harmony with them. For example, once we learned that our bodies cannot make vitamins C and B12 (and countless others), we under- stood that we needed to incorporate them into our diet.
We can learn similar lessons from the quirks in our anatomy. For example, by understanding the weak spots in our lower backs, we can engage postures that strengthen those weak spots such as stand-up desks. By understanding that we are better evolved to eat less often and much less carbohydrates, we can strive for a diet that better suits our physiology, leading to greater health. And by understanding the errors in our memories and our information processing, we can work to counter our biases and frequent miscalculations and make better decisions toward building a better world.