What Will Humans Look Like 10,000 Years From Now? Predicting the Future from the Past 10,000 Years of Evolution

The video opens with a question about our hands. They are the same hands that once threw spears, carried prey, and tore things apart with tools. Today their role has shifted to bringing cooked food to our mouths, yet it is sometimes said that they are still designed for an ancient environment. The video begins by asking whether this view is true.

To predict the future, we first need to look back at the past. Modern humans, Homo sapiens, appeared about 300,000 years ago, and for most of that time humans lived in hunter-gatherer societies. Evolution proceeds as individuals with traits suited to their environment survive and leave offspring. The video therefore explains that the human body is fundamentally suited to the hunter-gatherer era.

About 10,000 years ago, however, agriculture began. Humans stopped chasing food and started growing it, settled in one place, lived alongside livestock, and eventually built cities where many people lived. According to the video, this change in environment led humans to evolve in directions they had never gone before. The video gives three examples.

The first is the ability to digest lactose, found in milk and other dairy, even after reaching adulthood. Normally, mammals lose the ability to digest lactose once they become adults. But some humans evolved to retain this ability into adulthood. The video notes that this ability is thought to have been an advantage in leaving offspring.

The second is the shrinking of the jaw. Human bones and muscles develop in response to mechanical load. The large jaws needed to grind fibrous plants are thought to have become smaller as humans began eating meat and, later, cooking their food.

According to the video, the shrinking of the jaw and the muscles that move it may have allowed the brain to develop further, which may have been one factor behind humanity's great advances. On the other hand, many people today suffer from problems with their wisdom teeth. The video says this is partly because the shrinking jaw left no room for wisdom teeth to grow in.

The third is immune function. Urban environments, home to many people as well as livestock, had a major impact on human immunity. Highly dangerous epidemics cannot spread unless large numbers of people—the fuel for infection, so to speak—are gathered in the same place. Many such diseases also originated in other animals, then became able to infect humans, and eventually to spread from person to person. Some of them, like the plague and smallpox, affected the entire world.

When humans settled down and lived in cities, population density rose and infectious diseases spread more easily. People with immune traits that gave them an advantage against the pathogens circulating in that environment are thought to have been more likely to survive and leave offspring.

However, the video adds that today, changes in sanitation have reduced our exposure to diverse microbes, making the immune system more prone to imbalance. This is thought to be one reason people overreact to normally harmless substances such as pollen and develop allergies.

From an evolutionary perspective, 10,000 years is not a particularly long time. Even so, as we have seen, human genes show a number of changes from the past 10,000 years alone. So what will happen over the next 10,000 years?

Here the video returns to the basics of evolution. What ultimately matters in evolution is which individuals managed to leave offspring. For that reason, evolution does not necessarily move in the direction of greater ability. The traits that are advantageous for leaving offspring in the environment of the time are what get passed on to the next generation. The word "degeneration" is often used as the opposite of evolution, but the video explains that degeneration is, properly speaking, also a form of evolution.

As an example, consider someone who can run extremely fast. In a hunter-gatherer society, this trait is extremely important. Such a person is more likely to catch prey—that is, to obtain food before starving—and thus more likely to leave offspring. In an agricultural society, however, running speed might not matter as much. In fact, because leg muscles consume a lot of energy, it could even be a disadvantage for leaving offspring during a famine.

In this way, predicting what humans will be like in 10,000 years also requires predicting the environment of the next 10,000 years. The video acknowledges that this is especially tricky in the modern era. For example, in an age when food is not scarce, running speed has little effect on survival. What matters then is how that trait affects finding a mate. This also involves factors such as social structure, so it could very well change over 10,000 years.

Even so, if we assume that today's civilized society continues for the next 10,000 years, there are some factors we can expect to remain unchanged. The video picks three of them and predicts what traits each will bring to humans 10,000 years from now.

The first is pressure to weed out highly aggressive individuals. In a civilized society, highly aggressive individuals are thought to be at a disadvantage when it comes to leaving offspring. This could produce an effect in humans similar to the one that turned some wild animals into domesticated ones. This is known as human "self-domestication."

In many mammals, it is known that breeding only the least aggressive individuals over many generations also changes their bodies. Specifically, the skeleton becomes more slender, the skull becomes flatter, and the differences between males and females become smaller. The video predicts that these traits may become more prominent in humans 10,000 years from now compared with today.

The second is an abundance of food. For most of human history, famines in which food nearly ran out were a fact of life. As a result, humans evolved bodies that actively store fat when calories are plentiful. Today, however, this trait is one of the causes of obesity and diabetes.

The video therefore raises the possibility that individuals whose metabolism is optimized for ancient environments may find it harder to find a mate and leave offspring in the future. As a result, it says, humans 10,000 years from now may gain weight less easily than they do today.

On the other hand, the video points out that the ability to produce nutrients in the body that can easily be obtained from food may decline. A precedent for this is vitamin C. Unlike many other animals, apes, including humans, cannot synthesize vitamin C in their bodies. Because our ancestors lived in environments rich in fruit, the gene involved in synthesizing vitamin C was no longer necessary for survival. That gene changed over generations until it eventually stopped functioning entirely. In the same way, the video predicts that humans 10,000 years from now may depend on food for nutrients that they can currently synthesize in their bodies without any problem.

The third is the advancement of medicine. Medical technology has made great strides over the past few centuries, greatly improving the chances of recovering from conditions that were once fatal. The video says it is clear that, as a result, more people have been able to leave offspring. Put another way, there are people who could not have been born without advanced medical care.

The example the video gives is childbirth. Because humans have well-developed brains, their heads are large compared with those of other mammals. In addition, because humans walk on two legs, their pelvises are relatively narrow. As a result, babies at birth are just barely small enough to pass through the mother's birth canal. If a baby's head were any larger, it would not have been unusual in ancient times for both mother and child to face mortal danger.

Today, however, a variety of measures can address this, and it is not unusual for both mother and child to survive and go on to have more offspring. This makes genes for both narrow pelvises and large heads more likely to be passed on to the next generation. The video therefore predicts that humans 10,000 years from now may have fewer natural births than today. However, the video frames this not as a bad thing, but as something that could be called the fruit of medical progress.

The video closes by saying that whatever humans look like 10,000 years from now, it will be the result of adapting to the environments from the past up to that era. The same is true of humans today: the history of evolution is etched into the bodies of modern people, and that history will also be passed on to the next generation. This is the video's conclusion.