Your expressive face tells the story of human evolution — conveying emotion was essential
There are reasons you look the way you do.
- A panel of eight experts in the evolution of the human face have collaborated on a new summary of how we've changed.
- Their paper promotes the importance of social interaction as a factor in the structure of our visages.
- We can visually express more than 20 categories of emotion. Early humans not so much.
Your face is not yours alone — written there are traces of your parents, grandparents, and ancestors. Now a paper published in Nature Ecology and Evolution makes an even broader case. Your face, that so-familiar visage you see in the mirror each day, contains a living, breathing history in its features of humankind's evolution from the earliest African hominids to, well, you. What's revealed, its authors say, is that the ability to communicate and thus thrive in social contexts deserves to be given more credit as a key factor in the evolution of our appearance.
A gathering of face experts
Image source: Rodrigo Lacruz
The new paper is the work of eight of the world's foremost experts in the evolution of the human face. At its heart is an attempt to answer a very basic question: Why do we look so different from other, extinct hominins, as well as our primate cousins such as chimpanzees and bonobos? Our faces have gotten smaller over time. The question is why? "We know that other factors such as diet, respiratory physiology, and climate have contributed to the shape of the modern human face," says Paul O'Higgins of the University of York, one of the experts involved, "but to interpret its evolution solely in terms of these factors would be an oversimplification."
University of Arizona's William Kimbell, also involved in the study, puts it this way: "We are a product of our past. Understanding the process by which we became human entitles us to look at our own anatomy with wonder and to ask what different parts of our anatomy tell us about the historical pathway to modernity."
The shrinking human jaw
Our changing diet is thought to be the primary factor in the reduction in size of our jaws that began as we started cooking and cutting-up our foods about 10,000 years ago. We no longer needed such crushing mandibles to make our way through our omnivorous diet, and the benefit of strong chewing capabilities became less of a factor in natural selection. It's likely no coincidence that the trend toward a smaller chin accelerated with advent of the beginning of the agriculture.
As far as other areas of the face, the story is even more interesting. It seems that our transition to community living mandated a greater ability to communicate well. While the scientists hypothesize that the strong brows of Homo erectus and the Neanderthals were effective for communicating aggression, strength, and domination — as we see in the great apes — these signals were no longer as beneficial to humans as we began to gather into communities.
"We can now use our faces to signal more than 20 different categories of emotion via the contraction or relaxation of muscles", O'Higgins says. "It's unlikely that our early human ancestors had the same facial dexterity, as the overall shape of the face and the positions of the muscles were different."
The changes to our physiology have endowed us with the ability to communicate far more effectively in groups, and it's easy to imagine how getting along with others led to a greater chance of reproducing. Before the arrival of language, in particular, the ability to facially communicate friendliness, sympathy, and other feelings was critical in gaining others' acceptance.
Are we there yet?
O'Higgins looks back, and forward. Image source: University of York
According to O'Higgins, most likely we're not done evolving. "There are limits on how much the human face can change, however. For example, breathing requires a sufficiently large nasal cavity. However, within these limits, the evolution of the human face is likely to continue as long as our species survives, migrates and encounters new environmental, social and cultural conditions."
So, that face. Your face. It's part of a long, ongoing story starring your ancestors and their ancestors. It's an interesting way to see that person looking back at you from the mirror.
To create wiser adults, add empathy to the school curriculum.
- Stories are at the heart of learning, writes Cleary Vaughan-Lee, Executive Director for the Global Oneness Project. They have always challenged us to think beyond ourselves, expanding our experience and revealing deep truths.
- Vaughan-Lee explains 6 ways that storytelling can foster empathy and deliver powerful learning experiences.
- Global Oneness Project is a free library of stories—containing short documentaries, photo essays, and essays—that each contain a companion lesson plan and learning activities for students so they can expand their experience of the world.
This is what the world will look like, 250 million years from now
To us humans, the shape and location of oceans and continents seems fixed. But that's only because our lives are so short.
The future of education and work will rely on teaching students deeper problem-solving skills.
- Asking kids 'What do you want to be when you grow up?' is a question that used to make sense, says Jaime Casap. But it not longer does; the nature of automation and artificial intelligence means future jobs are likely to shift and reform many times over.
- Instead, educators should foster a culture of problem solving. Ask children: What problem do you want to solve? And what talents or passions do you have that can be the avenues by which you solve it?
- "[T]he future of education starts on Monday and then Tuesday and then Wednesday and it's constant and consistent and it's always growing, always improving, and if we create that culture I think that would bring us a long way," Casap says.
These Jurassic predators resorted to cannibalism when hit with hard times, according to a deliciously rare discovery.
- Rare fossil evidence of dinosaur cannibalism among the Allosaurus has been discovered.
- Scientists analyzed dinosaur bones found in the Mygatt-Moore Quarry in western Colorado, paying special attention to bite marks that were present on 2,368 of the bones.
- It's likely that the predatory carnivore only ate their already-dead peers during times when resources were scarce.
As a doctor, I am reminded every day of the fragility of the human body, how closely mortality lurks just around the corner.