Big ideas.
Once a week.
Subscribe to our weekly newsletter.
Are humans domesticated animals?
If the neural crest hypothesis is correct, humans are the first domesticated animals. But who, or what, tamed us?

Animal husbandry is perhaps 30,000 years old, starting with the humble dog. Several species came afterward and domestication was born. What most people may not know is that there’s one species that became domesticated even before the dog, and that’s us. But to understand why, we need to know the nuances of the various definitions of domestication and where they come from. Domestication is generally defined as the purposeful breeding of a plant or animal for human benefit. But science looks at it a tad differently.
The science of domestication
Domestication syndrome is the physical traits that occur to a wild plant or animal as it becomes domesticated. For mammals this includes things like floppy ears, shorter muzzles, curly tails, white hair—particularly prominent in dogs, cats, and rabbits, and lighter colored coats. Other physical characteristics include smaller brains, shorter limbs, and smaller teeth. There are changes in personality too which include sociability, tameness, and even juvenile behavior.
Darwin first noticed this not among the unique species of the Galapagos but in the common pigeon along the Thames and how much it differed from the fancier varieties Londoners kept as pets. Those beautiful, compliant ceremonial doves? They're actually just white pigeons. He likened the differences to the kept bird’s better diet, comfier living conditions, and its ability to interbreed with other domesticated birds, leading to hybridization. Humans and animals entirely similar in the respect that each is shaped by the environmental circumstances thrust upon them.
Is it diet, breeding, and a cushier lifestyle that causes domestication, or something more? Credit: Getty Images.
The Soviet experiment
In 1959, Soviet geneticist Dmitry Belyaev began breeding wild foxes to study how they became domesticated over time. He took the most social ones and mated them. Over 10 generations, Belyaev witnessed a dramatic change in them. Personality wise, the foxes became more sociable and playful over time. Physically, they began to have floppier ears, smaller skulls, and patches of white fur in their coats. The males also started to more closely resemble females. What he had found was that domesticated mammals who spent a lot of time with humans and were bred for sociability over generations exhibited similar traits.
This discovery of domestication syndrome didn’t just focus the lens on animals but back onto us as well. Our jaws are small and rounded, our brains smaller than that of the Neanderthal—one of our closest (though extinct) ancestors. At the time, being a discomforting thought with little hard evidence to support it, the idea that humans are also in a way domesticated was lost, mostly, because it was hard to test.
Since that time, a combination of advancements in genetics, our understanding of human evolution, and a number of important paleontological discoveries have led to greater insight into our own species’ development. This, in turn, had led to a recognition of this strange phenomenon and once again thrust it into the spotlight. In 2014, an international team of scientists made a discovery that changed the way we look at domestication and human evolution dramatically.
The neural crest cell hypothesis
Richard Wrangham of Harvard, Adam Wilkins, now at Humboldt University in Germany, and Tecumseh Fitch at the University of Vienna, Austria, came up with what’s known as the neural crest cell hypothesis. Together, they found what connects all of the traits associated with domestication including changes to the teeth, ears, skin, and temperament. They all originate in the neural crest.
The neural crest is a congregation of cells that forms in a developing embryo. This tiny mass eventually breaks up and becomes different tissues in the body, including the adrenal glands—responsible for the stress response (and in a way, temperament), cartilage in the ears, melanocyte cells which create the skin’s pigment, and dentin which forms the teeth. They also earmarked dozens of genes associated with domestication, each one linking back to the neural crest.
Researchers could then compare domestication genes with those found in the genomes of an animal's wild counterpart. Surprisingly, the genetic changes that caused domestication were the same across all mammalian species, whether it be from wolves to dogs, European bison to cattle, or Neanderthals to humans. The genetic changes that drove these transitions were identical.
So if humans domesticated other species, who or what domesticated us?
If we look at human domestication as changes that allowed us to work and live together to survive, you can say evolution tamed us. Around 100,000 years ago, our species began living closer together. It would’ve been better to cooperate with new neighbors than fight them. Around that same time, the pronounced brow ridges and long faces humans once had were being replaced by smoother, softer, more feminine features.
Scientists believe that the same forces which helped shape domestic animals also affected us. Credit: Getty Images.
One theory is that when our bodies and brains grew bigger, we became less aggressive. Larger animals with bigger brains tend to act more peaceably. This is domestication through natural selection. Those humans who were less aggressive and more cooperative were more likely to pass on their genes, and so these traits became a signature part of our species. Then, interacting with other species over time molded them in the same way. Keep in mind that this is all very new to science and more research must be done to better understand the phenomenon.
To learn more about domestication, click here.

How tiny bioelectronic implants may someday replace pharmaceutical drugs
Scientists are using bioelectronic medicine to treat inflammatory diseases, an approach that capitalizes on the ancient "hardwiring" of the nervous system.
Left: The vagus nerve, the body's longest cranial nerve. Right: Vagus nerve stimulation implant by SetPoint Medical.
- Bioelectronic medicine is an emerging field that focuses on manipulating the nervous system to treat diseases.
- Clinical studies show that using electronic devices to stimulate the vagus nerve is effective at treating inflammatory diseases like rheumatoid arthritis.
- Although it's not yet approved by the US Food and Drug Administration, vagus nerve stimulation may also prove effective at treating other diseases like cancer, diabetes and depression.
The nervous system’s ancient reflexes
<p>You accidentally place your hand on a hot stove. Almost instantaneously, your hand withdraws.</p><p>What triggered your hand to move? The answer is <em>not</em> that you consciously decided the stove was hot and you should move your hand. Rather, it was a reflex: Skin receptors on your hand sent nerve impulses to the spinal cord, which ultimately sent back motor neurons that caused your hand to move away. This all occurred before your "conscious brain" realized what happened.</p><p>Similarly, the nervous system has reflexes that protect individual cells in the body.</p><p>"The nervous system evolved because we need to respond to stimuli in the environment," said Dr. Tracey. "Neural signals don't come from the brain down first. Instead, when something happens in the environment, our peripheral nervous system senses it and sends a signal to the central nervous system, which comprises the brain and spinal cord. And then the nervous system responds to correct the problem."</p><p>So, what if scientists could "hack" into the nervous system, manipulating the electrical activity in the nervous system to control molecular processes and produce desirable outcomes? That's the chief goal of bioelectronic medicine.</p><p>"There are billions of neurons in the body that interact with almost every cell in the body, and at each of those nerve endings, molecular signals control molecular mechanisms that can be defined and mapped, and potentially put under control," Dr. Tracey said in a <a href="https://www.youtube.com/watch?v=AJH9KsMKi5M" target="_blank">TED Talk</a>.</p><p>"Many of these mechanisms are also involved in important diseases, like cancer, Alzheimer's, diabetes, hypertension and shock. It's very plausible that finding neural signals to control those mechanisms will hold promises for devices replacing some of today's medication for those diseases."</p><p>How can scientists hack the nervous system? For years, researchers in the field of bioelectronic medicine have zeroed in on the longest cranial nerve in the body: the vagus nerve.</p>The vagus nerve
<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNTYyOTM5OC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY0NTIwNzk0NX0.UCy-3UNpomb3DQZMhyOw_SQG4ThwACXW_rMnc9mLAe8/img.jpg?width=1245&coordinates=0%2C0%2C0%2C0&height=700" id="09add" class="rm-shortcode" data-rm-shortcode-id="f38dbfbbfe470ad85a3b023dd5083557" data-rm-shortcode-name="rebelmouse-image" data-width="1245" data-height="700" />Electrical signals, seen here in a synapse, travel along the vagus nerve to trigger an inflammatory response.
Credit: Adobe Stock via solvod
<p>The vagus nerve ("vagus" meaning "wandering" in Latin) comprises two nerve branches that stretch from the brainstem down to the chest and abdomen, where nerve fibers connect to organs. Electrical signals constantly travel up and down the vagus nerve, facilitating communication between the brain and other parts of the body.</p><p>One aspect of this back-and-forth communication is inflammation. When the immune system detects injury or attack, it automatically triggers an inflammatory response, which helps heal injuries and fend off invaders. But when not deployed properly, inflammation can become excessive, exacerbating the original problem and potentially contributing to diseases.</p><p>In 2002, Dr. Tracey and his colleagues discovered that the nervous system plays a key role in monitoring and modifying inflammation. This occurs through a process called the <a href="https://www.nature.com/articles/nature01321" target="_blank" rel="noopener noreferrer">inflammatory reflex</a>. In simple terms, it works like this: When the nervous system detects inflammatory stimuli, it reflexively (and subconsciously) deploys electrical signals through the vagus nerve that trigger anti-inflammatory molecular processes.</p><p>In rodent experiments, Dr. Tracey and his colleagues observed that electrical signals traveling through the vagus nerve control TNF, a protein that, in excess, causes inflammation. These electrical signals travel through the vagus nerve to the spleen. There, electrical signals are converted to chemical signals, triggering a molecular process that ultimately makes TNF, which exacerbates conditions like rheumatoid arthritis.</p><p>The incredible chain reaction of the inflammatory reflex was observed by Dr. Tracey and his colleagues in greater detail through rodent experiments. When inflammatory stimuli are detected, the nervous system sends electrical signals that travel through the vagus nerve to the spleen. There, the electrical signals are converted to chemical signals, which trigger the spleen to create a white blood cell called a T cell, which then creates a neurotransmitter called acetylcholine. The acetylcholine interacts with macrophages, which are a specific type of white blood cell that creates TNF, a protein that, in excess, causes inflammation. At that point, the acetylcholine triggers the macrophages to stop overproducing TNF – or inflammation.</p><p>Experiments showed that when a specific part of the body is inflamed, specific fibers within the vagus nerve start firing. Dr. Tracey and his colleagues were able to map these relationships. More importantly, they were able to stimulate specific parts of the vagus nerve to "shut off" inflammation.</p><p>What's more, clinical trials show that vagus nerve stimulation not only "shuts off" inflammation, but also triggers the production of cells that promote healing.</p><p>"In animal experiments, we understand how this works," Dr. Tracey said. "And now we have clinical trials showing that the human response is what's predicted by the lab experiments. Many scientific thresholds have been crossed in the clinic and the lab. We're literally at the point of regulatory steps and stages, and then marketing and distribution before this idea takes off."<br></p>The future of bioelectronic medicine
<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNTYxMDYxMy9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYzNjQwOTExNH0.uBY1TnEs_kv9Dal7zmA_i9L7T0wnIuf9gGtdRXcNNxo/img.jpg?width=980" id="8b5b2" class="rm-shortcode" data-rm-shortcode-id="c005e615e5f23c2817483862354d2cc4" data-rm-shortcode-name="rebelmouse-image" data-width="2000" data-height="1125" />Vagus nerve stimulation can already treat Crohn's disease and other inflammatory diseases. In the future, it may also be used to treat cancer, diabetes, and depression.
Credit: Adobe Stock via Maridav
<p>Vagus nerve stimulation is currently awaiting approval by the US Food and Drug Administration, but so far, it's proven safe and effective in clinical trials on humans. Dr. Tracey said vagus nerve stimulation could become a common treatment for a wide range of diseases, including cancer, Alzheimer's, diabetes, hypertension, shock, depression and diabetes.</p><p>"To the extent that inflammation is the problem in the disease, then stopping inflammation or suppressing the inflammation with vagus nerve stimulation or bioelectronic approaches will be beneficial and therapeutic," he said.</p><p>Receiving vagus nerve stimulation would require having an electronic device, about the size of lima bean, surgically implanted in your neck during a 30-minute procedure. A couple of weeks later, you'd visit, say, your rheumatologist, who would activate the device and determine the right dosage. The stimulation would take a few minutes each day, and it'd likely be unnoticeable.</p><p>But the most revolutionary aspect of bioelectronic medicine, according to Dr. Tracey, is that approaches like vagus nerve stimulation wouldn't come with harmful and potentially deadly side effects, as many pharmaceutical drugs currently do.</p><p>"A device on a nerve is not going to have systemic side effects on the body like taking a steroid does," Dr. Tracey said. "It's a powerful concept that, frankly, scientists are quite accepting of—it's actually quite amazing. But the idea of adopting this into practice is going to take another 10 or 20 years, because it's hard for physicians, who've spent their lives writing prescriptions for pills or injections, that a computer chip can replace the drug."</p><p>But patients could also play a role in advancing bioelectronic medicine.</p><p>"There's a huge demand in this patient cohort for something better than they're taking now," Dr. Tracey said. "Patients don't want to take a drug with a black-box warning, costs $100,000 a year and works half the time."</p><p>Michael Dowling, president and CEO of Northwell Health, elaborated:</p><p>"Why would patients pursue a drug regimen when they could opt for a few electronic pulses? Is it possible that treatments like this, pulses through electronic devices, could replace some drugs in the coming years as preferred treatments? Tracey believes it is, and that is perhaps why the pharmaceutical industry closely follows his work."</p><p>Over the long term, bioelectronic approaches are unlikely to completely replace pharmaceutical drugs, but they could replace many, or at least be used as supplemental treatments.</p><p>Dr. Tracey is optimistic about the future of the field.</p><p>"It's going to spawn a huge new industry that will rival the pharmaceutical industry in the next 50 years," he said. "This is no longer just a startup industry. [...] It's going to be very interesting to see the explosive growth that's going to occur."</p>Japan finds a huge cache of scarce rare-earth minerals
Japan looks to replace China as the primary source of critical metals
- Enough rare earth minerals have been found off Japan to last centuries
- Rare earths are important materials for green technology, as well as medicine and manufacturing
- Where would we be without all of our rare-earth magnets?
What are the rare earth elements?
<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xOTA2MTM0Ni9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYzODExMjMyMn0.owchAgxSBwji5IofgwKtueKSbHNyjPfT7hTJrHpTi98/img.jpg?width=980" id="fd315" class="rm-shortcode" data-rm-shortcode-id="d8ed70e3d0b67b9cbe78414ffd02c43e" data-rm-shortcode-name="rebelmouse-image" />(julie deshaies/Shutterstock)
<p>The rare earth metals can be mostly found in the second row from the bottom in the Table of Elements. According to the <a href="http://www.rareearthtechalliance.com/What-are-Rare-Earths" target="_blank"><u>Rare Earth Technology Alliance</u></a>, due to the "unique magnetic, luminescent, and electrochemical properties, these elements help make many technologies perform with reduced weight, reduced emissions, and energy consumption; or give them greater efficiency, performance, miniaturization, speed, durability, and thermal stability."</p><p>In order of atomic number, the rare earths are:</p> <ul> <li>Scandium or Sc (21) — This is used in TVs and energy-saving lamps.</li> <li>Yttrium or Y (39) — Yttrium is important in the medical world, used in cancer drugs, rheumatoid arthritis medications, and surgical supplies. It's also used in superconductors and lasers.</li> <li>Lanthanum or La (57) — Lanthanum finds use in camera/telescope lenses, special optical glasses, and infrared absorbing glass.</li> <li>Cerium or Ce (58) — Cerium is found in catalytic converters, and is used for precision glass-polishing. It's also found in alloys, magnets, electrodes, and carbon-arc lighting. </li> <li>Praseodymium or Pr (59) — This is used in magnets and high-strength metals.</li> <li>Neodymium or Nd (60) — Many of the magnets around you have neodymium in them: speakers and headphones, microphones, computer storage, and magnets in your car. It's also found in high-powered industrial and military lasers. The mineral is especially important for green tech. Each <a href="https://www.reuters.com/article/us-mining-toyota/as-hybrid-cars-gobble-rare-metals-shortage-looms-idUSTRE57U02B20090831" target="_blank"><u>Prius</u></a> motor, for example, requires 2.2 lbs of neodymium, and its battery another 22-33 lbs. <a href="https://pubs.usgs.gov/sir/2011/5036/sir2011-5036.pdf" target="_blank"><u>Wind turbine batteries</u></a> require 450 lbs of neodymium per watt. </li> <li>Promethium or Pm (61) — This is used in pacemakers, watches, and research.</li> <li>Samarium or Sm (62) — This mineral is used in magnets in addition to intravenous cancer radiation treatments and nuclear reactor control rods.</li> <li>Europium or Eu (63) — Europium is used in color displays and compact fluorescent light bulbs.</li> <li>Gadolinium or Gd (64) — It's important for nuclear reactor shielding, cancer radiation treatments, as well as x-ray and bone-density diagnostic equipment.</li> <li>Terbium or Tb (65) — Terbium has similar uses to Europium, though it's also soft and thus possesses unique shaping capabilities .</li> <li>Dysprosium or Dy (66) — This is added to other rare-earth magnets to help them work at high temperatures. It's used for computer storage, in nuclear reactors, and in energy-efficient vehicles.</li> <li>Holmium or Ho (67) — Holmium is used in nuclear control rods, microwaves, and magnetic flux concentrators.</li> <li>Erbium or Er (68) — This is used in fiber-optic communication networks and lasers.</li> <li>Thulium or Tm (69) — Thulium is another laser rare earth.</li> <li>Ytterbium or Yb (70) — This mineral is used in cancer treatments, in stainless steel, and in seismic detection devices.</li> <li>Lutetium or Lu (71) — Lutetium can target certain cancers, and is used in petroleum refining and positron emission tomography.</li></ul>Where Japan found is rare earths
<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xOTA2MTM0OC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY1MTA0NzUxNn0.N3t_iKf6lnnoJ6yVUtl8-wNZICEG2ZxyPzm9ZdE99ks/img.jpg?width=980" id="021b7" class="rm-shortcode" data-rm-shortcode-id="d9dd843fde547a0b69f8798aca18a706" data-rm-shortcode-name="rebelmouse-image" />Minimatori Torishima Island
(Chief Master Sergeant Don Sutherland, U.S. Air Force)
<p>Japan located the rare earths about 1,850 kilometers off the shore of <a href="https://en.wikipedia.org/wiki/Minami-Tori-shima" target="_blank"><u>Minamitori Island</u></a>. Engineers located the minerals in 10-meter-deep cores taken from sea floor sediment. Mapping the cores revealed and area of approximately 2,500 square kilometers containing rare earths.</p><p>Japan's engineers estimate there's 16 million tons of rare earths down there. That's <a href="https://minerals.usgs.gov/minerals/pubs/historical-statistics/ds140-raree.xlsx" target="_blank"><u>five times</u></a> the amount of the rare earth elements ever mined since 1900. According to <a href="https://www.businessinsider.com.au/rare-earth-minerals-found-in-japan-2018-4?r=US&IR=T" target="_blank"><u>Business Insider</u></a>, there's "enough yttrium to meet the global demand for 780 years, dysprosium for 730 years, europium for 620 years, and terbium for 420 years."</p><p>The bad news, of course, is that Japan has to figure out how to extract the minerals from 6-12 feet under the seabed four miles beneath the ocean surface — that's the <a href="https://www.nature.com/articles/s41598-018-23948-5" target="_blank"><u>next step</u></a> for the country's engineers. The good news is that the location sits squarely within Japan's Exclusive Economic Zone, so their rights to the lucrative discovery will be undisputed.</p>Physicist creates AI algorithm that may prove reality is a simulation
A physicist creates an AI algorithm that predicts natural events and may prove the simulation hypothesis.
Pixellated head simulation.
- Princeton physicist Hong Qin creates an AI algorithm that can predict planetary orbits.
- The scientist partially based his work on the hypothesis which believes reality is a simulation.
- The algorithm is being adapted to predict behavior of plasma and can be used on other natural phenomena.
Physicist Hong Qin with images of planetary orbits and computer code.
Credit: Elle Starkman
Are we living in a simulation? | Bill Nye, Joscha Bach, Donald Hoffman | Big Think
<span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="4dbe18924f2f42eef5669e67f405b52e"><iframe type="lazy-iframe" data-runner-src="https://www.youtube.com/embed/KDcNVZjaNSU?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span>Fight or flight? Why some people flee and others stand their ground
How different people react to threats of violence.
Eight women at the forefront of the world’s COVID-19 response
Beyond making up 70% of the world's health workers, women researchers have been at the cutting edge of coronavirus research.
