What Will Humans Look Like In 100,000 Years

A cute little speculative article imagines what humans might look like 100,000 years from now due to evolution after living in space for a while with a before and after picture.

Now

In 100,000 years

The article motivates its pictures as follows: 

In 2007, artist and researcher Nickolay Lamm partnered with computational geneticist Dr. Alan Kwan and came up with three illustrations. He first hypothesized what we might look like in twenty thousand years, the second in sixty thousand years, and the third 100 thousand years into the future.

According to Lamm, this is “one possible timeline” that takes into consideration both human evolution and advancements in technology and genetic engineering. Lamm and Kwan imagined a possible future where humans would have a much greater ability to control the human genome, and where their living environments might be much different than ours [1].

Here are some of the major changes that could happen, and the reasons why they might occur, according to Kwan and Lamm: 

A larger forehead 

The human forehead has been increasing in size since the fourteenth and fifteenth centuries. According to scientists, when you measure skulls from that time and compare them to our own, people today have less prominent facial features and higher foreheads [2]. It seems logical, then, to imagine a future where our skulls continue to grow to accommodate larger and larger brains. 

Changed Facial Features

Given the advancements we have already made in genetic engineering, Kwan based some of his hypotheses on the assumption that we will be even further ahead sixty thousand years from now. He argued that a greater ability to control the human genome will mean that evolution will have little effect on human facial features. Essentially, our faces will change depending on human preferences- like larger eyes, a straighter nose, and more symmetry between both sides of our faces. 

He also suggested that by then, it is possible that humans will have begun colonizing other planets. People living in places that are further from the sun, and therefore are less bright, may cause their eyes to get bigger to enhance vision. Skin may also be darker to lessen the damage from UV rays outside of earth’s protective atmosphere.

Additionally, he proposed that people will have thicker eyelids, and their frontal bone under their brow will be more pronounced. This will help humans to deal with the disruptive effects of cosmic rays. We already see these effects happening with today’s astronauts.

Kwan says that over the remaining forty thousand years, those features that humans selected for will become even more pronounced. One hundred thousand years from now, it is possible that humans’ eyes, for example, will seem unnervingly large compared to what we are used to today. 

Functional Necessities

Other, smaller changes may be things like larger nostrils. This will allow humans to breathe easier when they’re living on other planets. People may have denser hair to keep their larger heads warm. In an age, however, when you can genetically alter almost any feature about yourself, Kwan suggests that features make us look naturally human will become more favorable.

It is an interesting exercise although it misses some obvious points.

Time Horizons

The notion that this would happen over 100,000 years based upon past experience of the human species is not very credible for the kind of basic visual phenotypes focused upon.

Most of the common phenotypes associated with major "racial" types today evolved much more rapidly. There was no one in Europe who looked like a typical modern Northern European in 4000 BCE. 

Bantu expansion in Africa, in the same time period, caused one West African phenotype to become predominant in most of sub-Saharan Africa, leaving only small relict populations of "Paleo-Africans" like pygmies and Khoi-San people, and subtly reducing the distinctiveness of the typical linguistically Nilo-Saharan East African.

A lot of the distinctiveness of East Asian phenotypes is attributable to the selective sweep of the EDAR gene which is much older than either of the other two examples, but happened, when it did happen, in a matter of a few thousand years, not tens or hundreds of thousands of years.

Genetic engineering, to the extent it occurs, will likewise have its biggest impacts in a matter of a century or two, not thousands of years. And, while the article notes that some geneticists at the time put the prospects of this kind of genetic engineering thousands of years in future, CRISPER technology already available and still in its infancy with lots of room to improve, suggests that this is much less far off than expected in 2007 when it was done, especially for visually striking, but largely cosmetic features that involve only small numbers of genes like eye, hair and skin color, hair texture and curliness, propensity to tan, and freckles.

Genetic engineering will probably start with efforts to actively select against "defects" from Downs' syndrome to bad teeth and vulnerability to specific genetic diseases with simple recessive Mendelian inheritance patterns. Simple cosmetic adjustments that are well understood may follow. And, from there, the chase for enhancements, such as additional cones that allow people to see more colors, may begin. I see those steps taking perhaps a generation or two at a time to progress from one level to the next.

I fully expect the appearance of the average human to be significantly visually different by 3000 CE, not merely tens of thousands of years hence.

Admixture

Sufficiently far in the future, there will be few, if any, people who are phenotypically comparable to modern Europeans, due to admixture.

The world almost surely will see dramatically more admixture over the next few centuries than it has since the Bronze Age. In this regard Betty Crocker has probably been more predictive in forming a composite, mixed race, customer of the company:

For her 75th anniversary in 1996, a nationwide search found 75 women of diverse backgrounds and ages who embody the characteristics of Betty Crocker. The characteristics that make up the spirit of Betty Crocker are: enjoys cooking and baking; committed to family and friends; resourceful and creative in handling everyday tasks; and involved in her community. A computerized composite of the 75 women, along with the 1986 portrait of Betty, served as inspiration for the painting by internationally known artist John Stuart Ingle. The portrait was unveiled March 19, 1996, in New York City.

Better yet is this National Geographic image:

Selection On Standing Variation

Image from here.

The massive intercontinental admixture we are likely to see also reflects another key point of both natural evolution and selective breeding, which is that most evolutionary selection involves selection within the existing range of variation among people, rather than new mutations that prove beneficial, which are the exception.

Indeed, one of the real challenges in the first wave of genetic engineering will be to avoid the temptation to completely remove genetic diversity, biodiversity and neurodiversity from the human species when it seems to be a net minus in current conditions from the standing range of variation in humans only to discover that these traits may have currently unrecognized benefits sometime long in the future. Otherwise, the demise of human genetic diversity could mirror the mass extinction of species and languages on Earth during the late Holocene. 

Lots of the most important bits, like HLA immunity complexes and temperaments better suited to the world of the far future, are also largely invisible a priori although their functional connection to other traits may make that less true than one would expect as discussed below.

On the other hand, genetic engineering can revolutionize that analysis. For example, if we find a gene that is very valuable in extremely genetically dissimilar octopi that is total absent from vertebrate genetic diversity a few decades from now, we might very well use genetic engineering to make that a common variant in the human genome.

Self-Domestication

Humans are likely to continue to select for traits associated with domestication of animals, a process that is already well underway.

Darwin observed that domesticated animals share certain traits across species. Domesticates tend to have floppier ears than their wild counterparts, and curlier tails. They're smaller and have recessed jaws and littler teeth. Domestication also shrinks the amygdala, the brain's fear center, leading to a reduction in aggressive, fearful reactions.

Belyaev noticed that his domesticated foxes eventually developed black and white, or piebald, spots, now known to be a classic sign of domestication. Think of the black and white pelts of cows, horses, dogs, and cats – especially those white-footed felines we claim "wear socks."

The thing is, with the exception of docility, these characteristics don't do anything at all.

Research like Belyaev's made it apparent that if you select for friendliness and cooperation in foxes, you get a host of features that come along for the ride that don't serve a purpose – in evolutionary parlance they're non-adaptive, much like the male nipple. Together this suite of traits is called the "domestication syndrome."

For years scientists have recognized that domestication seems to preserve childlike psychological and physical tendencies, especially those that elicit care from parents and other adults. "Cuter" features. A little more helplessness. And friendliness towards humans, supporting Hare's argument. Recent science has helped piece together why this is.

During vertebrate development there is a strip of what are called neural crest cells running down the back of the embryo. As we grow inside the womb, these cells migrate throughout the body to help form the cartilage and bone of our face and jaw, the melanin-producing cells that give our skin pigment, and part of our peripheral nervous system. They also form our adrenal glands, which, among other functions, release cortisol — our "stress hormone" — and adrenaline, involved in our fight or flight response.

Domesticated animals have smaller adrenal glands. Hare believes selection for friendliness results in less neural crest migration, and as a result, less aggressive, reactionary behavior driven by adrenal hormones.

But fewer neural crest cells reaching their intended targets also influences the other traits driven by their voyage through the body, explaining the smaller snouts and jaws seen in domesticates, and white patches of fur lacking melanin. Scientists now know that domestication — whether artificial or natural — seems to involve selection on a gene called BAZ1B, which helps drive neural crest migration during development.

Baby faces are the future. Other related traits, like enhanced childhood language learning relative to adults, may also be the subject to genetic engineering in the future. William's Syndrome illustrates what this might look like, which bears some similarities to mythical elves:

Technology Facilitates Adaptation And Determines What Is Selected For

Technology can also reduce selective pressure on a lot of obvious physical features, like skin color, with things like Vitamin D supplements and sun screen picking up the slack.

Technology can also determine which human traits merit selection.

For example, for most of human history, food supplies with limited and irregular, and there was strong selection for a capacity to survive periods of famine. But in the modern world, selection is likely to focus on an ability to escape the downsides of obesity that present themselves in a more sedentary world where food is abundant and consistently available.

Physically wild movement and hyperactivity may have been beneficial in much of human history, while the future looks likely to reward a capacity to be still and focused.

Some traits may be the subject to genetic engineering, while other forms of non-genetic bioengineering like nutritional supplements, vaccines, and hormone treatments may also play important parts. Nutrition without genetics can prevent common visible consequences of malnutrition and can enhance height. Everyone in the future will probably be more health overall based upon a variety of genetic and non-genetic methods and cultural adaptations to modern technologies that we are struggling with now.

We might end up with genetic engineering that mitigates nearsightedness adapting to a world where reading fine print regularly is essentially, but if laser eye surgery continues to advance, that may not be a priority as other forms of bioengineering will do the trick.

Self-driving cars and other intelligent safety features in mechanical and chemical things may reduce the selective effects that our current society has against people who impulsively drive too recklessly, cross the street without carefully looking both ways, drink and drive, or otherwise engage in conduct that has grown much more deadly for the average persons than it did in the days where land travel was mostly by foot. Likewise, vulnerability to jet lag might be less important in an era of self-driving cars and AI safety features, when grogginess can be deadly, than in one without them.

Intelligence has lots of value in the modern world, but large infant head size also increases the risk of death to mother and child in natural child birth. But this risk may be alleviated in C-sections are universally and widely available, allowing for larger heads and bigger brains (even though average brain size seems to be declining in recent decades).

Another factor that has impeded brain size development is energy drain. The brain uses 20% of the body's energy demand while only 4% of its volume. But if more energy efficient neurons were genetically engineered somehow, that might make it more workable to have larger brains without the metabolic cost faced by prior vertebrates.

At some point, we might want to genetically engineer humans to have natural immunity to lots of diseases, but in the meantime, improved vaccines might make that a low priority.

The interactions of technology and selective pressures make what the future of humanity looks like difficult to predict. A hundred thousand years out, who knows? Maybe we'll look like this: