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The invention that made us human: Fire
Did fire change the development of the human brain?
- The earliest evidence for fire dates back nearly 440 million years.
- Our hominin ancestors first used natural wildfires to flush out prey and forage for food.
- Richard Wrangham's cooking hypothesis suggests that a ready supply of cooked food allowed the Homo lineage to develop its large, complex brains.
Of humanity's greatest inventions, fire remains as important today as in the time of our ancient ancestors. If not as apparent.
We have replaced the hearth with electric ovens and central heating, but the burning of fossil fuels accounts for 63.5 percent of U.S. electricity generation. We still heat our homes and cook our food with fire — just in a more roundabout manner.
We even use fire in ways our ancestors couldn't have imagined. The internal combustion engine has replaced animals and our own wobbly legs as the preferred method of travel. We can go farther in a day than the vast majority of our ancestors did in a lifetime and even escape the confines of our planet. Thanks to fire.
But fire has done more than create the energy that makes our lives comfortable. By one Harvard professor's account, fire altered the course of our evolution.
Fire, a brief history
Wildfires, such as this one at Yellowstone National Park, have been a recurring phenomenon for more than 440 million years.
First, some Chem 101. Fire requires three elements for its reaction: oxygen, a fuel, and a heat source. Since two of the three elements are provided naturally by plants, the history of fire became intricately tied to them.
Some of our earliest evidence for fire goes back 440 million years to the Silurian period, when Earth's climate stabilized and plants and animals began to move to land. Of note, this period provides the earliest fossil evidence of vascular plants.
From this point, fire becomes a recurrent phenomenon with times of high and low activity based on environmental conditions. During the Carboniferous period, atmospheric oxygen hit a record high of 31 percent and plants spread across the supercontinent Pangea, so charcoal records suggest a lot of fire activity during this period. Conversely, the pittance of charcoal from the Triassic period suggests low atmospheric oxygen and fewer plants.
Jumping a few million years to the late Miocene, hominins moved to the grasslands and begun to further diverge from their ape relatives — likely due to the difference between the African savanna and the dense jungle. Here, they would have also encountered wildfires with far more regularity.
We didn't start the fire
Prometheus Brings Fire to Mankind by Heinrich Fuger. Our early reliance on nature for fire draws parallels to later mythologies.
Low-hanging references aside, Billy Joel was on to something. Popular culture conjures the image of a caveman banging two stones together. Sparks fly, and then the eureka moment. Yet, our ancestors' first usage of fire probably wasn't a matter of control or invention. It was more likely opportunistic.
In a review for the Royal Society Philosophical Transactions B, J.A.J. Gowlett hypothesizes that hominins took advantage of natural wildfires for foraging. "For hominins," he writes, "benefits could include retrieval of birds eggs, rodents, lizards and other small animals, as well as invertebrates. Although fire does not create such resources, it renders them far more visible, and chance cooking might well improve their digestibility."
Gowlett notes that analogues to this behavior exist in the natural world today. Savanna chimpanzees use fires to locate resources, and several bird species follow fires to snatch up any prey flushed out by the smoke and flames. There has even been anecdotal evidence of some raptors, such as Australia's "firehawks," picking up smoldering wood from one fire and carrying it elsewhere to start another.
Early hominins would have also begun to discover fire's properties by observing and interacting with these blazes. For example, if a meaty morsel proved too raw, they may have learned to place it on embers to continue the cooking process.
Given our early reliance on nature for fire, it's little wonder that the theft of fire theme has appeared time and again in the world's mythologies.
But we kept it burning
It's difficult to follow the development of hominin control over fire because of what Gowlett calls its "disappearing act." Fire isn't as well preserved in the archeological record as, say, middens or flint tools. And progress was incremental, with fire control being learned in different places at different times.
Certain archeological sites have proffered a bounty of stone tools, suggesting long-term quartering. Such occupancy could mean hominins learned to at least maintain fire as far back as 2.5 million years ago. But direct evidence is scarce.
As we move forward, we see more evidence of hominins' control over fire. Archaeologists have discovered campfire traces and charred animal and plant remains at Wonderwerk Cave in South Africa. These have been dated back to approximately one million years ago. And the oldest known hearth, found at Qesem Cave, Israel, dates back more than 300,000 years ago.
Interestingly, archeologists aren't sure which hominin species got cozy at Qesem. "It is clearly different than [Homo] erectus and has affinities of both [Homo] sapiens and Neanderthals," Ran Barkai, Tel Aviv archaeologist, told National Geographic. "Since Neanderthals appear very late in the Levant and are of European origin, and since the Qesem teeth bear more resemblance to early Homo sapiens in the Levant, we believe they are closer to Homo sapiens."
Hearths and campfires tell us hominins could maintain fires for cooking and warmth. They do not, however, prove our ability to create fire. After transferring a brand from a wildfire, a tribe member could have been given fire duty and tasked with fueling the fire to prevent its extinguishing.
Good evidence for fire creation appears around 120,000 years ago, when hominins had access to twine, a requisite to developing the bow drill. And archeologists have dated two glues used in hafting, bark pitch and gypsum plaster, to between 50 and 100 thousand years ago. Neither of these can be prepared without fire.
At this point, Gowlett argues, the invention of fire belongs to our ancestors. "[A]n understanding is emerging that fire use is not a single technology or process, but that several scales of use, and probably several intensifying technologies, evolved over a long period, intertwined, and sometimes eventually became bound together," he writes.
Fire (and food) for thought
Cooked meats are easier to chew and digest; as a result, our bodies can extract more nutrients from the same amount of meat. Similarly, cooking vegetables increases levels of healthy stuff like antioxidants. That's because the cooking process breaks down the plants' cell walls and, like meat, makes them easier to digest and process. (Though, it is a tradeoff. Some veggies are healthier raw, and it depends on how you cook them.)
Wrangham argues that the ability to create cooked foods shaped the brains and bodies of our Homo ancestors. Since our ancestors spent less energy digesting foods and could draw out additional nutrients, they had more to nutrients to spend, and evolution spent those dividends on maintaining larger brains — not to mention smaller teeth and jaws. Larger brains allowed us to process more information, create more dynamic social groups, and adjust to unfamiliar habitats. All of which benefited us evolutionarily.
With that said, the cooking hypothesis has its detractors. Some argue there is little proof that humans were cooking or maintaining fire in concurrence with Homo erectus' brain-size explosion (roughly 1.5 million years ago). It's also possible that a diet of raw meat and veggies could have provided the necessary nutrients for bigger brains.
Other hypotheses exist to explain the increase in hominin brain size. The social brain hypothesis, for example, argues our brains evolved to meet the challenges of living in large social groups. But even here, fire plays a role. Remember that before our ancestors could ignite fire, they had to maintain it. This required a division of labor, which is only possible in a species with a highly structured social network.
Fire may or may not ultimately prove to be principal in our evolutionary development. For any such hypothesis more evidence is needed — though fire, cooked food, and social networks likely all played a part.
Without a doubt, fire has proved a primary mover in the evolution of civilization. It helped us migrate to climates that would otherwise prove inhospitable. It was essential to the development of cuisine, agriculture, metallurgy, architecture, and a host of other industries. In short, the invention of fire has taken humanity places no other species has gone.
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How would the ability to genetically customize children change society? Sci-fi author Eugene Clark explores the future on our horizon in Volume I of the "Genetic Pressure" series.
- A new sci-fi book series called "Genetic Pressure" explores the scientific and moral implications of a world with a burgeoning designer baby industry.
- It's currently illegal to implant genetically edited human embryos in most nations, but designer babies may someday become widespread.
- While gene-editing technology could help humans eliminate genetic diseases, some in the scientific community fear it may also usher in a new era of eugenics.
Tribalism and discrimination<p>One question the "Genetic Pressure" series explores: What would tribalism and discrimination look like in a world with designer babies? As designer babies grow up, they could be noticeably different from other people, potentially being smarter, more attractive and healthier. This could breed resentment between the groups—as it does in the series.</p><p>"[Designer babies] slowly find that 'everyone else,' and even their own parents, becomes less and less tolerable," author Eugene Clark told Big Think. "Meanwhile, everyone else slowly feels threatened by the designer babies."</p><p>For example, one character in the series who was born a designer baby faces discrimination and harassment from "normal people"—they call her "soulless" and say she was "made in a factory," a "consumer product." </p><p>Would such divisions emerge in the real world? The answer may depend on who's able to afford designer baby services. If it's only the ultra-wealthy, then it's easy to imagine how being a designer baby could be seen by society as a kind of hyper-privilege, which designer babies would have to reckon with. </p><p>Even if people from all socioeconomic backgrounds can someday afford designer babies, people born designer babies may struggle with tough existential questions: Can they ever take full credit for things they achieve, or were they born with an unfair advantage? To what extent should they spend their lives helping the less fortunate? </p>
Sexuality dilemmas<p>Sexuality presents another set of thorny questions. If a designer baby industry someday allows people to optimize humans for attractiveness, designer babies could grow up to find themselves surrounded by ultra-attractive people. That may not sound like a big problem.</p><p>But consider that, if designer babies someday become the standard way to have children, there'd necessarily be a years-long gap in which only some people are having designer babies. Meanwhile, the rest of society would be having children the old-fashioned way. So, in terms of attractiveness, society could see increasingly apparent disparities in physical appearances between the two groups. "Normal people" could begin to seem increasingly ugly.</p><p>But ultra-attractive people who were born designer babies could face problems, too. One could be the loss of body image. </p><p>When designer babies grow up in the "Genetic Pressure" series, men look like all the other men, and women look like all the other women. This homogeneity of physical appearance occurs because parents of designer babies start following trends, all choosing similar traits for their children: tall, athletic build, olive skin, etc. </p><p>Sure, facial traits remain relatively unique, but everyone's more or less equally attractive. And this causes strange changes to sexual preferences.</p><p>"In a society of sexual equals, they start looking for other differentiators," he said, noting that violet-colored eyes become a rare trait that genetically engineered humans find especially attractive in the series.</p><p>But what about sexual relationships between genetically engineered humans and "normal" people? In the "Genetic Pressure" series, many "normal" people want to have kids with (or at least have sex with) genetically engineered humans. But a minority of engineered humans oppose breeding with "normal" people, and this leads to an ideology that considers engineered humans to be racially supreme. </p>
Regulating designer babies<p>On a policy level, there are many open questions about how governments might legislate a world with designer babies. But it's not totally new territory, considering the West's dark history of eugenics experiments.</p><p>In the 20th century, the U.S. conducted multiple eugenics programs, including immigration restrictions based on genetic inferiority and forced sterilizations. In 1927, for example, the Supreme Court ruled that forcibly sterilizing the mentally handicapped didn't violate the Constitution. Supreme Court Justice Oliver Wendall Holmes wrote, "… three generations of imbeciles are enough." </p><p>After the Holocaust, eugenics programs became increasingly taboo and regulated in the U.S. (though some states continued forced sterilizations <a href="https://www.uvm.edu/~lkaelber/eugenics/" target="_blank">into the 1970s</a>). In recent years, some policymakers and scientists have expressed concerns about how gene-editing technologies could reanimate the eugenics nightmares of the 20th century. </p><p>Currently, the U.S. doesn't explicitly ban human germline genetic editing on the federal level, but a combination of laws effectively render it <a href="https://academic.oup.com/jlb/advance-article/doi/10.1093/jlb/lsaa006/5841599#204481018" target="_blank" rel="noopener noreferrer">illegal to implant a genetically modified embryo</a>. Part of the reason is that scientists still aren't sure of the unintended consequences of new gene-editing technologies. </p><p>But there are also concerns that these technologies could usher in a new era of eugenics. After all, the function of a designer baby industry, like the one in the "Genetic Pressure" series, wouldn't necessarily be limited to eliminating genetic diseases; it could also work to increase the occurrence of "desirable" traits. </p><p>If the industry did that, it'd effectively signal that the <em>opposites of those traits are undesirable. </em>As the International Bioethics Committee <a href="https://academic.oup.com/jlb/advance-article/doi/10.1093/jlb/lsaa006/5841599#204481018" target="_blank" rel="noopener noreferrer">wrote</a>, this would "jeopardize the inherent and therefore equal dignity of all human beings and renew eugenics, disguised as the fulfillment of the wish for a better, improved life."</p><p><em>"Genetic Pressure Volume I: Baby Steps"</em><em> by Eugene Clark is <a href="http://bigth.ink/38VhJn3" target="_blank">available now.</a></em></p>
It's hard to stop looking back and forth between these faces and the busts they came from.
- A quarantine project gone wild produces the possibly realistic faces of ancient Roman rulers.
- A designer worked with a machine learning app to produce the images.
- It's impossible to know if they're accurate, but they sure look plausible.
How the Roman emperors got faced<a href="https://payload.cargocollective.com/1/6/201108/14127595/2K-ENGLISH-24x36-Educational_v8_WATERMARKED_2000.jpg" ><img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDQ2NDk2MS9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYyOTUzMzIxMX0.OwHMrgKu4pzu0eCsmOUjybdkTcSlJpL_uWDCF2djRfc/img.jpg?width=980" id="775ca" class="rm-shortcode" data-rm-shortcode-id="436000b6976931b8320313478c624c82" data-rm-shortcode-name="rebelmouse-image" alt="lineup of emperor faces" data-width="1440" data-height="963" /></a>
Credit: Daniel Voshart<p>Voshart's imaginings began with an AI/neural-net program called <a href="https://www.artbreeder.com" target="_blank">Artbreeder</a>. The freemium online app intelligently generates new images from existing ones and can combine multiple images into…well, who knows. It's addictive — people have so far used it to generate nearly 72.7 million images, says the site — and it's easy to see how Voshart fell down the rabbit hole.</p><p>The Roman emperor project began with Voshart feeding Artbreeder images of 800 busts. Obviously, not all busts have weathered the centuries equally. Voshart told <a href="https://www.livescience.com/ai-roman-emperor-portraits.html" target="_blank" rel="noopener noreferrer">Live Science</a>, "There is a rule of thumb in computer programming called 'garbage in garbage out,' and it applies to Artbreeder. A well-lit, well-sculpted bust with little damage and standard face features is going to be quite easy to get a result." Fortunately, there were multiple busts for some of the emperors, and different angles of busts captured in different photographs.</p><p>For the renderings Artbreeder produced, each face required some 15-16 hours of additional input from Voshart, who was left to deduce/guess such details as hair and skin coloring, though in many cases, an individual's features suggested likely pigmentations. Voshart was also aided by written descriptions of some of the rulers.</p><p>There's no way to know for sure how frequently Voshart's guesses hit their marks. It is obviously the case, though, that his interpretations look incredibly plausible when you compare one of his emperors to the sculpture(s) from which it was derived.</p><p>For an in-depth description of Voshart's process, check out his posts on <a href="https://medium.com/@voshart/photoreal-roman-emperor-project-236be7f06c8f" target="_blank">Medium</a> or on his <a href="https://voshart.com/ROMAN-EMPEROR-PROJECT" target="_blank" rel="noopener noreferrer">website</a>.</p><p>It's fascinating to feel like you're face-to-face with these ancient and sometimes notorious figures. Here are two examples, along with some of what we think we know about the men behind the faces.</p>
Caligula<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDQ2NDk4Mi9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY3MzQ1NTE5NX0.LiTmhPQlygl9Fa9lxay8PFPCSqShv4ELxbBRFkOW_qM/img.jpg?width=980" id="7bae0" class="rm-shortcode" data-rm-shortcode-id="ce795c554490fe0a36a8714b86f55b16" data-rm-shortcode-name="rebelmouse-image" data-width="992" data-height="558" />
One of numerous sculptures of Caligula, left
Nero<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDQ2NTAwMC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY1NTQ2ODU0NX0.AgYuQZzRQCanqehSI5UeakpxU8fwLagMc_POH7xB3-M/img.jpg?width=980" id="a8825" class="rm-shortcode" data-rm-shortcode-id="9e0593d79c591c97af4bd70f3423885e" data-rm-shortcode-name="rebelmouse-image" data-width="992" data-height="558" />
One of numerous sculptures of Nero, left
To understand ourselves and our place in the universe, "we should have humility but also self-respect," Frank Wilczek writes in a new book.
Debating is cognitively taxing but also important for the health of a democracy—provided it's face-to-face.
- New research at Yale identifies the brain regions that are affected when you're in disagreeable conversations.
- Talking with someone you agree with harmonizes brain regions and is less energetically taxing.
- The research involves face-to-face dialogues, not conversations on social media.
There are two kinds of identity politics. One is good. The other, very bad. | Jonathan Haidt<span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="6f0e52833af5d35adab591bb92d79f8e"><iframe type="lazy-iframe" data-runner-src="https://www.youtube.com/embed/l-_yIhW9Ias?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span><p>Unsurprisingly, harmonious synchronization of brain states occurred when volunteers agreed, similar to <a href="https://www.researchgate.net/publication/322764116_Creativity_and_Flow_in_Surgery_Music_and_Cooking_An_Interview_with_Neuroscientist_Charles_Limb" target="_blank">group flow</a>—the coordination of brain waves that hip-hop and jazz musicians (among others) experience when performing together. Coordination exceeds the social, into the neurological. As the team writes, "talking during agreement was characterized by increased activity in a social and attention network including right supramarginal gyrus, bilateral frontal eye-fields, and left frontopolar regions."</p><p>This contrasts with argumentative behavior, in which "the frontoparietal system including bilateral dorsolateral prefrontal cortex, left supramarginal gyrus, angular gyrus, and superior temporal gyrus showed increased activity while talking during disagreement."</p><p>Senior author Joy Hirsch notes that our brain is essentially a social processing network. The evolutionary success of humans is thanks to our ability to coordinate. Dissonance is exhausting. Overall, <a href="https://www.sciencedaily.com/releases/2021/01/210113090938.htm" target="_blank">she says</a>, "it just takes a lot more brain real estate to disagree than to agree," comparing arguments to a symphony orchestra playing different music. </p><p>As the team notes, language, visual, and social systems are all dynamically intertwined inside of our brain. For most of history, yelling at one another in comment sections was impossible. Arguments had to occur the old-fashioned way: while staring at the source of your discontent. </p>
People of the "left-wing" side yell at a Trump supporter during a "Demand Free Speech" rally on Freedom Plaza on July 6, 2019 in Washington, DC.
Credit: Stephanie Keith/Getty Images<p>Leading us to an interesting question: do the same brain regions fire when you're screaming with your fingers on your Facebook feed? Given the lack of visual feedback from the person on the other side of the argument, likely not—as it is unlikely that many people would argue in the same manner when face-to-face with a person on the other side of a debate. We are generally more civil in real life than on a screen.</p><p>The researchers point out that seeing faces causes complex neurological reactions that must be interpreted in real-time. For example, gazing into someone's eyes requires higher-order processing that must be dealt with during the moment. Your brain coordinates to make sense of the words being spoken <em>and</em> pantomimes being witnessed. This combination of verbal and visual processes are "generally associated with high-level cognitive and linguistic functions."</p><p>While arguing is more exhausting, it also sharpens your senses—when a person is present, at least. Debating is a healthy function of society. Arguments force you to consider other viewpoints and potentially come to different conclusions. As with physical exercise, which makes you stronger even though it's energetically taxing, disagreement propels societies forward.</p>In this study, every participant was forced to <em>listen</em> to the other person. As this research was focused on live interactions, it adds to the literature of cognitive processing during live interactions and offers insights into the cognitive tax of anger. Even anger is a net positive when it forces both sides to think through their thoughts and feelings on a matter. As social animals, we need that tension in our lives in order to grow. Yelling into the void of a comments section? Not so helpful. <p>--</p><p><em>Stay in touch with Derek on <a href="http://www.twitter.com/derekberes" target="_blank">Twitter</a> and <a href="https://www.facebook.com/DerekBeresdotcom" target="_blank">Facebook</a>. His most recent book is</em> "<em><a href="https://www.amazon.com/gp/product/B08KRVMP2M?pf_rd_r=MDJW43337675SZ0X00FH&pf_rd_p=edaba0ee-c2fe-4124-9f5d-b31d6b1bfbee" target="_blank" rel="noopener noreferrer">Hero's Dose: The Case For Psychedelics in Ritual and Therapy</a>."</em></p>
In a joint briefing at the 101st American Meteorological Society Annual Meeting, NASA and NOAA revealed 2020's scorching climate data.