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Why We Still Can’t Read the Writing of the Ancient Indus Civilization

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A typical seal of the Indus Valley Civilization, containing undeciphered signs (Credit: Harappa Archaeological Research Project, in Yadav et al 2010 PLOS One)

A typical seal of the Indus Valley Civilization, containing undeciphered signs. (Credit: Harappa Archaeological Research Project, in Yadav et al 2010 PLOS One)

Today, when we’ve unlocked the secrets of Egyptian hieroglyphs, Maya writing and hosts of far lesser known scripts, it seems as though there’s nothing left for enterprising epigraphers. Fear not, for there are actually a number of ancient writing systems still to be cracked. They include texts of the Olmec and Zapotec (Mesoamerican cultures preceding the Classic Maya), Proto-Elamite (writings of the earliest civilization of present-day Iran) and Rongorongo of Easter Island.

But if it’s fame you’re after (as well as intense scrutiny and even death threats) there’s no better challenge than the symbols of the Indus Valley Civilization, which flourished some 4,000 years ago in present-day Pakistan and northwest India.

From this culture, archaeologists have recovered several thousand short inscriptions, most with just 4 or 5 signs. There is no consensus on how to read them, although dozens of speculative decipherments have been proposed over the past century.

Complicating efforts, the underlying language the script is tied to is disputed, and there are complex modern-day political ramifications to the question. Rival ethnic groups claim to descend from this once-great civilization and knowing its language would help cement cultural ties. Hence the reported threats to scholars immersed in the matter.

Furthermore, some researchers go so far as to deny the existence of an underlying language. That is, they argue the Indus inscriptions were not true writing — visible signs that unambiguously represent speech — but an alternate symbolic system similar to emblems, conveying more general meanings.

Despite naysayers and challenges, decipherment efforts have progressed in the past decade, thanks to better databases of texts and new computational methods for finding patterns among the signs. Here’s what we know, for now.

That Lesser-known Great Civilization

4,000 years ago the Indus Valley civilization held an estimated one million people spread over a Texas-sized region, twice the area of contemporary Egypt or Mesopotamia. Its largest excavated cities, Harappa and Mohenjo-daro, exhibit levels urban planning that rival modern standards, including grid-like streets, water management and the oldest toilets. Yet there’s no suggestion of royal, religious or military might — no grand palaces, temples or defensive fortifications. And after flourishing between 1900-2600 BC, it’s unclear what happened to the people, or if any populations today can count themselves as their descendants.

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Ruins of Mohenjo-daro, one of the largest cities of the Indus Valley Civilization. (Credit: Robinson, Cracking the Indus Script, Nature, vol 526, 2015)

One reason archaeologists, and average people, don’t know much about the Indus, is that it was only discovered in the 1920s. Since then, researchers have identified more than 1,000 settlements, which from the surface appear to belong to the culture. But less than 10 percent have been systematically excavated, due in part to unrest along the India-Pakistan border.

Another reason the Indus is elusive: that undeciphered script.

The Indus Inscriptions

Several thousand Indus texts have been discovered, mostly from Harappa and Mohenjo-daro, but also in far-flung lands of trading partners along the Persian Gulf and in Mesopotamia (and it’s probable the Indus were exposed to the idea of writing by these literate Mesopotamians). The majority are engraved on small stone seals, about one inch squared, above the image of an animal, such as a bull, elephant or unicorn-like creature. Fewer inscriptions are found on clay tablets, pottery and metal objects.

Examples of short inscriptions on seals and tablets from the Indus (Credit: Rao et al, A Markov Model of the Indus Script, PNAS vol 106, 2009)

Examples of short inscriptions on seals and tablets from the Indus. (Credit: Rao et al, A Markov Model of the Indus Script, PNAS vol 106, 2009)

With an average of just 4 or 5 signs, the brevity of most inscriptions poses a challenge for decipherment efforts. It’s also among the reasons that some scholars argue these characters are not true writing. Most other civilizations with a writing system have left examples that are hundreds of characters long. The longest example of Indus script, by contrast, is less than 30 characters.

Since 2004, there’s even been a standing $10,000 prize for anyone who discovers an Indus text over 50 characters, offered by an anonymous donor and valid through the lifetime of historian Steve Farmer, a vocal opponent of the view that the Indus civilization was literate.

Tallying all the characters appearing on all known texts, researchers count between 400 and 700 distinct Indus signs. In part, their estimates differ because of subjectivity in judging how much variation is permissible for a single sign. For instance, my handwritten “a” probably looks different than your “a,” but they are the same character. Regardless, having several hundred characters suggests the script — if it was writing — was likely logosyllabic, meaning signs represented full words as well as syllabic sounds. Other logosyllabic systems we’ve deciphered include Mesopotamian cuneiform (~600 signs) and Mayan glyphs (~800 signs).

How to Read Long-lost Scripts

Scholars have deciphered many extinct writing systems, such as Egyptian hieroglyphs, Mesopotamian cuneiform and, most recently, a considerable portion of Maya glyphs. Aside from the short inscriptions, why does Indus give us so much trouble?

Successful decipherment efforts have followed similar courses (Part 3). Researchers cataloged the possible characters and their variations to infer the nature of the system — alphabetic, syllabic, logographic, etc. Then they found patterns in the distribution and frequency of signs. For instance, some characters may commonly occur at the beginning of lines or others may usually cluster together.

Though there’s some disagreement, we’re probably at that point for the Indus script. But serious decipherment breakthroughs have relied on three key elements so far absent from the Indus corpus:

1) Proper names, such as kings or cities, known from records of contemporaneous cultures. During the process of deciphering Egyptian hieroglyphs, scholars benefited from the mention of rulers like Ptolemy and Cleopatra in ancient Greek texts, understood at the time. As for the Indus, we don’t know any historical figures or certain place names.

2) A bi- or trilingual inscription, which records the same text in both known and unknown writing systems. For Egypt, that was the famous Rosetta stone, a fractured slab transcribing a priestly decree in two Egyptian scripts and ancient Greek. No such thing has been found for the Indus.

3) The language the script transcribes. For Egypt, successful translators correctly reasoned that hieroglyphs represented Coptic, a language still used by the Egyptian Coptic Church. And indigenous people of Mesoamerica continue to speak the words of Maya glyphs.

But the actual identity of the Indus language (or languages) is contested and clouded by modern politics. Presently, many scholars (here, here) argue for an ancient form of Dravidian, a family of languages found today in mostly southern India, but also pockets of northern India and Pakistan, near the heart of the Indus Valley Civilization. Alternatively, some favor an Indo-European language, related to ancient Sanskrit, which supports Hindu nationalist claims to the culture. Still others propose different indigenous language families, like Munda, or no language at all.

Where We Stand

As early as 1966, archaeologist Shri B. B. Lal concluded the texts were normally read from right to left. But, as Indus scholar Bryan K. Wells wrote in 2015, that is “about the only fact that most researchers can agree on” (page 7). This conclusion is based on spacing of characters: rightmost signs are aligned comfortably at the edge, whereas leftmost signs hang, get squeezed or pushed lower.

The degree of disorder in different sequences. Indus inscriptions fall near writing systems, between DNA (top) and computer code (bottom) (Credit: Rao, Probabilistic Analysis of an Ancient Undeciphered Script, Computer, April 2010)

The degree of disorder in different sequences. Indus inscriptions fall near writing systems, between DNA (top) and computer code (bottom) (Credit: Rao, Probabilistic Analysis of an Ancient Undeciphered Script, Computer, April 2010)

For decades, researchers have used statistical analyses to show that certain signs often cluster together, suggesting words and/or word-order (what we would call syntax) exist in the texts (here, here, here) — an important counter to claims that Indus signs are not true writing. More recently, computer scientists have reinvigorated efforts. One approach analyzes how random or predictable the order of signs is within a text. By this measure, known as conditional entropy, Indus inscriptions appear like known writing systems, which fall between highly ordered sequences like computer code and disordered ones like DNA code. Other methods using statistics and probability theory have brought similar conclusions: Indus inscriptions exhibit a degree of predictability characteristic of true writing.

Reading that putative writing will take future research. Ancient DNA may soon shed light on the ancestry of the Indus people, providing clues about their language. And there’s always hope that future excavations will uncover more informative texts, a Rosetta stone of the Indus.

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Ecology

What if a jolt of electricity could make you happy?

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Scientists found a way to literally spark joy using joly of electricity. (Credit: icon99/shutterstock)

Scientists found a way to literally spark joy using jolts of electricity. (Credit: icon99/shutterstock)

People all around the world (or at least where Netflix is available) have been exhausting themselves of late trying to “spark joy” in their lives. The urge comes from cleaning guru Marie Kondo, whose philosophy rests on the principle that we should rid our homes and minds of things that don’t inspire bursts of pleasure.

The message resonates, in part, because it ties positivity to the world of material things. Happiness is in our minds. So having a tangible mechanism for producing joy is understandably comforting.

But there’s a simpler way to spark joy, if we really want to get literal about it. Any emotion we feel has a physical cause inside our brains. Electrical charges pass from neuron to neuron, spreading ripples of thought and feeling. What we call happiness is just electricity. And now researchers say they’ve found a remarkably specific means of triggering the electrical fireworks that add up to happiness in our brains. By electrically stimulating a brain region known as the cingulum, scientists created spontaneous laughter and a sense of calm and joy in three different patients.

The find could lead to treatments for anxiety and depression, and it hints at insights into the very roots of our emotions themselves.

An artist's illustration shows how an electrode tapped into the cingulum. (Credit: From Bijanki et al, J. Clin. Invest. (2019). Courtesy of American Society for Clinical Investigation)

An artist’s illustration shows how an electrode tapped into the cingulum. (Courtesy of American Society for Clinical Investigation)

Unexpected Bliss

The young woman is clad in hospital garb, sitting upright in a bed. A white hospital cap mushrooms above her head, wires splay from its rear. She’s due for brain surgery in a few days to treat a difficult, disruptive kind of epilepsy. She’s been worried and anxious.

She breaks into a radiant smile, laughter flowing uninhibited.

“I’m kind of like smiling because I can’t help it,” she says. A bit later, “Sorry, that’s just a really good feeling. That’s awesome.”

Neuroscientists just administered a tiny jolt of electricity to wires threaded through her skull and into her brain. The wires are there to guide surgeons to the source of her seizures. But before the procedure, she’s agreed to play guinea pig to a team of Emory University researchers.

Patients like her offer an unprecedented opportunity for researchers to test the workings of various brain regions with unparalleled specificity. By delivering targeted bursts of electricity through the electrodes, they can watch what happens when specific neural circuits are activated.

The team was sending small bursts of electricity to her cingulum, a horseshoe of brain matter that links to regions associated with emotion, self-assessment, social interaction and motivation, among other things. It’s also known to regulate anxiety and depression.

This kind of research, though hardly common, is not new. The patient’s reaction is.

“It was really exciting,” says Kelly Bijanki, a neuroscientist at Emory University who studies behavioral neuromodulation. She was one of the scientists working with the young woman, whose name was not given for privacy reasons, that day. She says the kind of spontaneous joy she saw was unprecedented.

Experiments with brain stimulation have elicited laughter and smiles before. But those responses seemed mechanical. Bijanki says the patients usually described it as a purely motor response. “Their body has laughed, but there’s no content to it.”

This case was different. There was real warmth behind the laughter; true happiness in her voice. At one point, the patient reported she was “so happy she could cry,” the researchers write in their paper.

“The way she was laughing was really infectious,” Bijanki says. “The whole room felt different: she was laughing, she was having a good time, and not afraid. Just that social, emotional contagion took over.”

Further tests confirmed the response. They conducted sham trials, telling the patient that they were providing stimulation when they weren’t. She didn’t react. They tested various levels of stimulation and saw that the more electricity they delivered, the stronger the joyous reaction was. The pattern remained the same: An initial burst of exultation faded into a state of happy relaxation after several seconds.

The researchers found no drawbacks to the treatment, either, they report in a paper in the Journal of Clinical Investigation. Her language skills and memory remained perfectly intact, and they saw no ill aftereffects of the stimulation.

In a screengrab from the scientists' experiment, the patient feels overwhelming joy even while pondering her dog dying. (Credit:)

In a screengrab from the scientists’ experiment, the patient feels overwhelming joy even while pondering her dog dying. (Credit: Bijanki et al, Journal of Clinical Investigation)

Put to the Test

The woman’s impending surgery would require her to remain awake while surgeons probed inside her skull. Their goal was to cut out the tissue responsible for her epilepsy, but it’s a game of millimeters. Doctors must remove enough to ensure that seizures don’t recur, but without causing permanent harm. The patient’s seizures appeared to emanate from a region near to language processing centers. Her job was to stay awake while surgeons worked, reading and talking to ensure they wouldn’t excise anything important.

The brain stimulation turned out to work so well that doctors were able to cut out completely the drugs used to manage anxiety during this type of brain surgery. Those medications can make patients sleepy and unresponsive, so the anesthesiologist decided to stop them midway through. The young woman, her skull opened to surgical tools, breezed through.

“During the surgery … she was telling me jokes about her dad, where prior to turning on the stimulation she had been crying and hyperventilating and right on the edge of panic,” Bijanki says.

To confirm their findings, the researchers performed the same tests with two more epilepsy patients with electrodes similarly implanted in their skulls. They got the same results. Jabs of electricity literally sparking joy inside their heads.

Putting Happiness to Work

It’s too simplistic to say the researchers have stumbled upon the place where joy hides within us. The brain is complex, and emotions well up from more than just a single place. Multiple brain regions are involved, and each contributes a facet to the emotion that we come to know as happiness.

In fact, researchers have found joy in another place in the brain as well. Sameer Sheth, a neurosurgeon at the Baylor College of Medicine, says that he’s had patients report feelings of euphoria during the course of his own work with brain stimulation as well. He was working with the ventral striatum, a region separate from the cingulum, though the two are tightly connected.

Stimulation to the ventral striatum has also produced the same sort of laughter and mood elevation that Bijanki saw, Sheth says.

But just because emotions are neurologically complex doesn’t mean there’s no value to understanding their origins.

“The more we understand this circuitry, the more we can fine tune how to harness that capability within an individual and the better we’ll be able to treat patients with mood disorders,” Sheth says.

Bijanki sees a range of applications for brain stimulation aimed at specific targets, beginning with the kind of surgeries the young epileptic was undergoing. By precluding the use of sedatives, the find might give brain surgeons new options when performing the kind of procedures the young woman went through. Allowing patients to give more feedback could make brain surgeries more targeted. It might also expand the scope of neurosurgery.

“The definition of what is an inoperable tumor is in some circumstances related to what is the surgeon reasonably comfortable with removing that isn’t going to ruin the patients life,” Bijanki says. “If the surgeon could know that in real time, then the surgery could proceed a little bit differently.”

More broadly, it could also find use as a treatment for mental disorders like depression, anxiety and PTSD. Bijanki imagines electrodes powered by a pacemaker battery delivering continuous, low-grade stimulation to patients with depressive disorders.

In the future, we may not even need wires to spark such emotions. Scientists are developing means of activating brain regions with pulses of light, or with ultrasound. Flashes and vibrations could one day deliver ease to the afflicted.

There are drugs that accomplish similar things today, of course, but those often have side effects, and the treatment isn’t always as direct. Brain stimulation could offer a better path.

Banish the Sadness

Bijanki was also struck by an odd side-effect of the stimulation. Though patients had no trouble recalling sad memories during treatment, the recollections were wholly powerless to make them feel unhappy.

“I remember my dog dying, and I remember that it was a sad memory, but I don’t feel sad about it right now,” the young woman said, as reported by the researchers in their paper. Another patient concurred, unable to recollect a tragic memory without smiling. The effect is slightly jarring, but it could provide a shield of sorts to those overcoming trauma.

Those suffering from PTSD often go through what’s called exposure therapy, where they are asked to repeatedly sift through memories of a traumatic event. The goal is to drain those memories of their fearsome power over time, but it is difficult, frightening work.

Paired with temporary brain stimulation that elides sadness, Bijanki thinks PTSD patients might be far better equipped to tread through painful memories.

Finding Balance

Ultimately, however, the goal of therapies involving brain stimulation isn’t to wipe out negative emotions.

Anger, sadness and fear are not without their merits, and banishing them could have unintended consequences. Sadness sits at the other end of the spectrum from happiness, for example. Taking away any of our emotions would be removing an aspect of our humanity. What’s more, we have emotions for a reason.

“Our emotions exist for a very specific purpose, to help us understand our world, and they’ve evolved to help us have a cognitive shortcut for what’s good for us and what’s bad for us,” Bijanki says.

That’s not the goal here, of course, though discussions about the ethical use of such technologies in the future is certainly warranted. Bijanki says that we’d need to be careful about applying things like brain stimulation that could be abused.

But, she’s not very worried about electrodes and electric shocks becoming the next designer drug. It’s just too technically demanding, she says. And the potential benefits for those with depression and other conditions are great.

Sometimes the bad can outweigh the good. In those cases, sparking a little joy might be what we need.

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NASA Picks Science Experiments to Send to the Moon This Year

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Virgin Galactic’s SpaceShipTwo Just Made its Second Trip to Space

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SpaceShipTwo under rocket power

SpaceShipTwo is carried into the air on the back of a plane, but then takes off into space under its own power. (Credit: Virgin Galactic)

On Friday, Virgin Galactic’s SpaceShipTwo flew in space for the second time, taking off from Mojave, California after days of weather delay. SpaceShipTwo took off at 8:07 a.m. PST carrying two pilots, a crewmember, and a nearly full weight of science projects from NASA.

Unlike most spaceflights that fire rockets from the ground, SpaceShipTwo is carried on the belly of a plane named WhiteKnightTwo before being released to propel itself into the upper atmosphere. After being carried 45,000 feet into the air, SpaceShipTwo successfully fired its rocket engine and reached suborbital space at approximately 8:55 a.m. PST. It coasted there for only a few minutes before heading back toward the ground, where it landed much like any other plane, roughly an hour after takeoff. Like all of SpaceShipTwo’s planned flights, this one was suborbital, meaning it does not reach orbit, and attains weightlessness for only a few minutes during its trip.

SpaceShipTwo made its maiden space voyage in December 2018, and today was its fifth powered flight in total. Unlike other private spaceflight companies like SpaceX, Virgin Galactic has made their main goal ferrying private citizens into space, and have been taking reservations for years.

The third crewmember today was Virgin Galactic’s Chief Astronaut Instructor and cabin evaluation lead. Her job today was to see how SpaceShipTwo feels from the cabin. Eventually, Virgin Galactic hopes to seat six passengers in place of the science payloads – or alongside them.

The spacecraft today also carried research projects from NASA’s Flight Opportunities program, which pairs research institutions with private companies who can fly their projects into space. The combined weight of the payloads put SpaceShipTwo at close to, but just under, the requirements for the commercial launch weight that NASA has specified. One of Virgin Galactic’s goals during this flight was testing how the vehicle flies with a greater weight distribution. Details will likely come later, but the flight was successful, which bodes well for the craft’s future in ferrying cargo as well as passengers.

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