Foods of abuse? Nutritionists consider food addiction

Cookies, chips, hot dogs and other ultraprocessed fare raise risk of runaway eating

By Tom Siegfried

From the earliest days of their evolution, guts and brains have been the best of friends.

It’s a mutually beneficial relationship. Guts prepare nourishment for delivery to the brain. And brains guide the behaviors needed to fill the gut with raw materials.

Even today, the primitive need to serve the gut’s hunger remains implanted in the human brain’s blueprint for directing behavior. But nowadays, food sometimes drives the brain to behave in ways that aren’t as useful for survival as the original evolutionary programming. In recent decades a mismatch has evolved between the food available to hungry humans and the brain circuitry designed to acquire it. Instead of scrounging for scarce sources of high-quality calories as in the era of hunting and gathering, modern humans are flooded with a glut of ultraprocessed foods, designed to appeal to the brain’s ancient evolutionary imperatives — whether the body needs the food or not.

“Ultraprocessed foods are the result of processing naturally occurring substances … and refining them into evolutionarily novel substances,” Ashley Gearhardt and Erica Schulte write in a review to appear in the 2021  Annual Review of Nutrition. Such substances tempt human taste buds with unnaturally high levels of ingredients that stimulate brain regions related to reward and motivation. As a result, consuming food today can engage behaviors similar to those accompanying addiction to drugs of abuse, write psychologists Gearhardt, of the University of Michigan, and Schulte, who recently moved from the University of Pennsylvania to Drexel University.

Traditionally, addiction experts have dismissed the notion that potato chips or ice cream could be addictive in the same sense as, say, heroin or alcohol. Those drugs can produce debilitating intoxication, and ceasing their use often leads to severe withdrawal symptoms. But by the 21st century, it became clear that tobacco also induces many features of addiction without intoxication. And quitting smoking might make people irritable but it does not inflict intolerable suffering.

“There is now scientific consensus that tobacco is a highly addictive substance,” say Gearhardt and Schulte. “Like tobacco, ultraprocessed foods do not trigger intoxication and do not cause life-threatening physical withdrawal symptoms, but people are prone to compulsively consume them even in the face of significant negative consequences.”

Tobacco’s addictive power demonstrates that addiction is not a simple condition with a clear biological signature that can be measured. Rather, addiction encompasses a cluster of symptoms; not all addicts exhibit all the symptoms. Ultraprocessed foods, Gearhardt and Schulte report, can in some people promote many of the behavioral symptoms associated with addiction to nicotine and other drugs.

Of course, people are always driven to obtain food — like water, it is necessary to survive. Nobody would claim that water is therefore addictive. But brain circuits that evolved to seek high-calorie foods such as nuts, fruits and meat are also stimulated by artificial concoctions loaded with sugars and fats.

Those ultraprocessed foods — such as chips, cookies, pizza and pastries — exploit the desire for tasty, high-calorie meals. So just as addictive drugs hijack the brain’s motivation and reward-seeking circuitry, so do ultraprocessed foods. Many people therefore consume those foods compulsively, despite undesirable consequences including excessive weight gain and various related illnesses, from diabetes to heart disease.

“Ultraprocessed foods have been a key factor in the rising global rates of obesity, diet-related disease and poor health,” Gearhardt and Schulte declare.

Beyond the appeal of sugars and fat, ultraprocessed foods often incorporate additional ingredients, such as attractive coloring, flavor enhancers and stabilizers to make chewing easier — helping deliver the reward to the brain faster and more efficiently.

“Ultraprocessed foods are designed to optimize not only the magnitude of the reward signal in the brain through high doses of calorie-dense ingredients and additives but also the speed with which that reward is delivered,” Gearhardt and Schulte point out.

And while even natural foods may be high in sugar, or in fat, ultraprocessed foods typically offer both extra fat plus sugar in the same package — ready to eat. Add in a vast marketing apparatus (unknown in prehistoric times), and the allure of ultraprocessed foods far exceeds the brain’s intrinsic desire for nutrition.

Foods that reward the brain

Remixing natural ingredients into novel concoctions with enhanced appeal was not invented by the food industry. It parallels the methods for preparing traditional addictive drugs by processing natural substances. Natural fruits can be fermented to make addictive drinks, for instance. Tobacco leaves are processed by drying to make nicotine delivery practical. Additional ingredients like sugars in alcoholic drinks and menthol in cigarettes boost the reward signal delivered to the brain. And just as making ultraprocessed foods mimics the manufacture of drugs of abuse, their excessive consumption evokes similar self-destructive behaviors, recent studies have shown.

Those studies have relied on a research tool developed at Yale University called the Yale Food Addiction Scale, based on the behavioral criteria used for diagnosing substance abuse disorders. Such behavioral indicators include lack of control over consuming a substance, continued consumption despite adverse consequences and unsuccessful attempts to cease use of the substance. No one symptom defines addiction; out of 11 symptoms, the presence of two to three indicates mild addiction, four to five suggest moderate addiction, and six or more indicate severe addiction.

Ultraprocessed foods are designed to optimize not only the magnitude of the reward signal in the brain but also the speed with which that reward is delivered.

Studies using the Yale scale show that obesity alone is not diagnostic of food addiction — not all obese people show addictive eating behaviors. But “there is consistent evidence that food addiction is higher for individuals with obesity,” Gearhardt and Schulte note. Such studies suggest that overall, about 15 percent of the US population may have food addiction (roughly the same prevalence as addiction to alcohol). And those studies consistently show that consuming ultraprocessed foods is linked to addictive eating behavior more commonly than natural fruits, vegetables or lean meats.

Besides their addiction-related behaviors, people diagnosed with food addiction on the Yale scale exhibit other similarities to people addicted to drugs. “More intense cravings, higher levels of depression and a greater likelihood of experiencing trauma” are all more common in both groups. Brain scan studies also find similar neural activity patterns in drug addicts and those diagnosed with food addiction.

“Studies using self-report, behavioral and neuroimaging methods have consistently concluded that ultraprocessed foods are the most likely to be associated with features of addiction,” Gearhardt and Schulte report.

Defining the problem

There’s no doubt that ultraprocessed foods motivate more consumption than nutritional needs alone dictate. But some researchers contend that food craving isn’t really a substance abuse disorder like alcoholism, but rather a behavioral addiction, like uncontrolled gambling. Resolving that issue would require identifying which specific chemical substances within the ultraprocessed foods are the key addictive agents.

So far research has not definitively identified such agents. But ultraprocessed foods do appear to evoke chemical changes in the brain (such as cellular sensitivity to some signaling molecules) to an extent that natural foods do not. On the whole, Gearhardt and Schulte conclude, research to date provides more support for the view that food addiction is substance-based rather than just a hard-to-break behavior.

They note, though, that “food addiction” is a term in need of refinement. For one thing, more research is needed to clarify which types of food are addictive and how to define them. Gearhardt and Schulte use “ultraprocessed food” to refer to industrially produced products containing such ingredients as high-fructose corn syrup and other additives. Mostly these foods — such as soft drinks, salty snacks, hot dogs and many other fast foods — overlap with “highly processed” foods spiked with refined carbohydrates and fats. Some are also sometimes called “hyperpalatable foods.”

It’s unclear which labels best identify foods likely to cause addictive behavior. And whether homemade versions of foods such as cookies count as addictive can depend on whether the ingredients used to bake them are processed, such as white flour.

Other issues with terminology enter the debate, of course, with respect to defining “addiction.” Some researchers continue to insist that excessive eating is a behavioral disorder rather than a substance addiction and scoff at the notion that Oreo cookies have anything in common with oxycodone.

But in a larger sense, arguing about whether food is addictive is fruitless. Addiction is not a naturally defined, invariant feature of biology like gravity or electric charge in physics. Addiction is a word. Its use should not be so rigidly constrained that the term can’t be used in ways to better aid those who suffer from self-destructive behaviors.

Tom Siegfried is a science writer and editor in the Washington, DC, area. His book The Number of the Heavens, about the history of the multiverse, was published in 2019 by Harvard University Press.

This article originally appeared in Knowable Magazine, an independent journalistic endeavor from Annual Reviews. 

The essential fly

Think before you swat: The much-maligned fly could be the key to ensuring future supplies of many of the world’s favorite foods

By Stephanie Pain

When entomologist Jonathan Finch turns his dust-caked car off the highway and onto the old wartime airstrip at Manbulloo, he knows what awaits him at the other end: 65,000 blooming mango trees, an indescribably horrible smell and the unmistakable buzz of excited blowflies.

These days, the old airstrip is the access road to the vast Manbulloo mango farm — 4 square kilometers of orchards near the town of Katherine in Australia’s Northern Territory. “It’s a beautiful place — remote, peaceful and blissfully shady beneath the trees,” Finch says. “But the smell is unbelievable. You just can’t get it off you.” Although we are talking on the phone, I get the impression he’s grinning. The loathsome odor, it turns out, is one he created himself. And it’s vital to his research into the pollinating prowess of flies.

Most of us don’t much like flies. Finch, though, is a big fan. He’s part of a team investigating the role that flies play in pollinating crops and whether, like honeybees, they might be managed to improve yields. He’s traveled from Western Sydney University on the other side of the continent to test a widely held belief among mango growers: If you leave out rotting carcasses, flies will come, and more flies mean more mangoes.

Mango growers realized way back that flies are important pollinators. “Some encourage flies by hanging large barrels from their trees and putting roadkill in them,” Finch says. “Other guys bring in a ton of fish and dump it in a heap in the middle of the orchard.” The farmers are convinced that the pungent bait makes a difference, and the biology of blowflies suggests that it might. Yet there’s no scientific proof that it does.

Blowflies are drawn to the smell of rotting flesh because they mate and lay their eggs on corpses and carcasses. They also forage among flowers to fill up on energy-boosting nectar and protein-rich pollen, transporting pollen from one flower to another in the process. So it seems fair to assume that extra flies will pollinate more flowers and the trees will bear more fruit. But do they?

To find out, Finch and his colleagues have coopted the Manbulloo farmers’ bait barrels and filled them with a mix of fish and chicken. With the temperature hovering around 30ºC (85ºF), the scent of decay soon wafts through the trees and the team can put the idea to the test.

Reputation reboot

Flies generally get a bad rap. People associate them with dirt, disease and death. “No one except entomologists really likes flies,” Finch says. Yet there’s good reason why we should cherish, encourage, even nurture them: Our future food supply could depend on it. The past few years have seen growing recognition that flies make up a large proportion of wild pollinators — but also that we know little about that side of their lives. Which sorts of fly pollinate what? How effective are they at delivering pollen where it’s needed? Which flies might we harness to boost future harvests — and how to go about it? With insect populations plummeting and honeybees under pressure from multiple threats, including varroa mites and colony collapse disorder, entomologists and pollination specialists are urgently trying to get some answers.

Animals are responsible for pollinating around 76 percent of crop plants, including a large number of globally important ones. Birds, bats and other small mammals do their bit, but insects do much more — pollinating flowers of many fruits, vegetables and nuts, from almonds to avocados, mangoes and melons, cocoa and coconuts, as well as crops grown to provide seed for future vegetable harvests. In a recent analysis for the Annual Review of Entomology, Australia-based biologist Romina Rader and colleagues from Australia, New Zealand and the US calculated that the world’s 105 most widely planted food crops that benefit from insect pollination are worth some $800 billion a year.

Bees, especially honeybees, get most of the credit, but overlooked and underappreciated is a vast army of beetles, butterflies, moths, ants, flies and more. In Rader’s analysis, only a handful of crops were visited exclusively by bees; most were visited by both bees and other insects. She and her colleagues assessed the contribution of each type of insect and found that flies were the most important pollinators after bees, visiting 72 percent of the 105 crops.

The realization that flies perform such a vital service has prompted a big push to learn how to make the most of these unsung heroes, by attracting them to fields and orchards and putting them to work in greenhouses and growing tunnels. As demand for food rises, growers will increasingly rely on managed pollinators reared for the job, and not just honeybees, says Rader. Flies will be crucial to ensuring future food security, she says.

Flies are amazingly diverse and near ubiquitous, living in just about every sort of habitat. Hundreds of species belonging to dozens of families have been reported visiting one or more crops, but two fly families stand out: hoverflies and blowflies. Rader’s analysis showed that hoverflies visit at least 52 percent of the crops studied and blowflies some 30 percent. Some species visit many different crops around the world: One hoverfly, the common drone fly (Eristalis tenax), has been recorded visiting 28 of Rader’s 105 crops, while the marmalade hoverfly ( Episyrphus balteatus) is close behind with 24, and the bluebottle Calliphora vicina (a blowfly), visits 8.  

Hoverflies and blowflies visit flowers to drink nectar, which fuels energetic activities like flying, and eat pollen to get the nutrients needed for sexual maturation. Like bees, many of these flies are hairy and trap pollen on the head and thorax as they feed. Larger flies can collect — and carry — hundreds and sometimes thousands of pollen grains as they fly from flower to flower. Unlike bees, which must forage close to their hive or nest, flies don’t have to provide for their young and can roam more widely.

They have other advantages too: Some flies forage earlier and later in the day; they tolerate a wider range of temperatures and are active when it’s too cool for bees; and they’ll be out and about even in wet and windy weather that keeps bees at home. And for those growing crops under glass or plastic, there’s potentially another plus. “Bees hate glasshouses and are inclined to sting you,” says Finch. Flies might prove more tolerant of working indoors. And crucially, says Finch: “Flies don’t sting.”

For now, honeybees still tend to do a larger share of crop pollination. With colonies trucked from crop to crop, managed bees generally far outnumber wild pollinators. Yet that’s not always the case. Flies breed faster, and when conditions are good, they can reach high densities. “Some species have fast life cycles and are very adaptable to changing conditions,” says Rader. What’s more, some of the most important hoverfly species are migratory, so huge numbers can turn up and far outnumber honeybees at crucial times of the year.

Recent radar studies tracking the migration of common European hoverflies (including the marmalade hoverfly) found that up to 4 billion fly northward into southern Britain each spring, a number not far short of all the honeybees in the whole of Britain. There have also been reports of great hoverfly migrations in the US, Nepal and Australia, suggesting that the phenomenon is widespread.

Even better, hoverflies provide valuable services besides pollination, says ecologist Karl Wotton, who heads the Genetics of Migration Lab at the University of Exeter in southwest England. Many species have predatory larvae with a voracious appetite for aphids, caterpillars and other soft-bodied pests. Wotton has calculated that the larvae of those billions of hoverflies that turn up in Britain each spring consume around 6 trillion aphids in the all-important early part of the growing season. “That’s around 6,000 tonnes of aphids or 20 percent of the population at that time of year,” he says. Other hoverflies have semiaquatic larvae that feed on waste organic material, usefully recycling nutrients. “It’s hard to think of a more beneficial group of insects,” says Wotton. “They provide great services — for free.”   

But how to harness flies to maintain — and boost — food production? One way is to attract more of them to fields and orchards. Schemes that encourage farmers to plant wildflowers, keep remnant native vegetation and leave grasslands uncut can be very effective at increasing the number and diversity of insects and expanding the pool of potential pollinators. Hoverflies and blowflies need a few extras if they are to proliferate, though: carrion for blowflies, access to aphids for some hoverflies and ponds or streams containing dung, decaying vegetation or carcasses for others.

Making fields and orchards more fly-friendly won’t always be enough. With that in mind, researchers round the world are trying to identify flies that can be reared commercially and released where and when their services are needed. But where to start? The vast majority of pollination studies have focused on bees, and although many species of flies have been reported visiting crops, in most cases little is known about how good they are at transporting pollen, let alone whether their visits translate into more fruit and vegetables.

That’s beginning to change. Scattered studies have logged how often flies visit flowers, counted the pollen grains stuck to their bodies and recorded crop yields, and found that some flies give bees a run for their money — and in some cases, outdo them. Researchers studying avocados in Mexico, for instance, found that the large green blowfly Chrysomya megacephala (aka the oriental latrine fly) visited more flowers in a given time than bees and carried pollen grains on parts of the body that would contact the stigma of the next avocado flower it visited. Studies in Israel, Malaysia and India all suggest that blowflies are effective at pollinating mangoes, while trials in the US and New Zealand showed that the European blue blowfly ( Calliphora vicina) produced as good a yield of leek and carrot seed as bees.

Hoverflies also show plenty of promise. In trials, a number of species have proved to be effective pollinators of seed crops, oilseed rape, sweet peppers and strawberries. Recent experiments in the UK, for instance, found that releasing a mixed bunch of hoverflies into cages of flowering strawberry plants increased the yield of fruit by more than 70 percent. What’s more, the strawberries were likely to be bigger, heavier and more perfectly formed.

Promise is one thing, practical application another. In Australia, researchers like Finch and Rader are working on a five-year, multi-institution project that, among other things, aims to match fly to crop, and then develop the best method of rearing them. At farms across the country, teams are putting candidate flies through their paces on crops as varied as mangoes and avocados, blueberries and vegetable seed.

At Manbulloo, Finch is focused on mangoes and whether the old farmers’ trick works. The stinking bait certainly attracted plenty of flies – but were they the same flies as those that growers saw visiting their mango flowers? They were. “Several large and common species seem to visit both carrion and flowers,” says Finch. Of those, one looked more promising than the others: the oriental latrine fly. “It’s big and hairy, which means it’s likely to carry and deposit a lot of pollen,” says Finch. “It’s also abundant, turns up in a lot of orchards and its larvae will eat anything that’s dead.”

After a temporary halt thanks to Covid-19, Finch plans to return to Manbulloo later this year to find out if the latrine flies live up to expectation. “They might just stick around the carrion all day, distracted by the disgusting smells,” he says. If they do venture through the orchard, he’ll monitor how many actually visit flowers and how often. The next test is whether the flies deliver pollen where it’s needed — on the stigmas of flowers that need fertilizing — a job that requires a microscope and plenty of patience. After all that, if the oriental latrine fly is still a contender, then it’s time to find out if its efforts pay off by releasing flies among trees protected from all other insects and measuring their success in mangoes.

The latrine fly might prove an effective pollinator, but that’s still not proof that the farmers’ carrion trick makes a difference. “For that, we’ll have to compare yields in orchards with carrion and without,” says Finch. If the growers are vindicated, then their cheap trick can be rolled out elsewhere. “If it turns out that they aren’t as good at depositing pollen as honeybees, then we may need to add more flies to compensate for their lower effectiveness.”

The idea of raising flies to produce food is slowly gaining traction, particularly for greenhouse crops. “Flies breed amazingly well and quickly on horrible things, which makes them cheap to use in glasshouses or release in fields,” says Finch. They are easy to transport as pupae and are expendable, unlike honeybees. Some growers are already reaping the benefits of purpose-bred flies. Tasmanian farmer Alan Wilson has been rearing his own blowflies for the past five years after discovering they improved his crop of high-value hybrid cauliflower seed. On the other side of the world in southern Spain, you can buy boxes of hoverfly pupae from Polyfly, the first company to produce hoverflies commercially for greenhouse crops.

Brilliant though flies are, they can have drawbacks. Those that attack livestock or people or are pests of other crops must be avoided at all costs. And of course there’s the yuck factor. In Spain, Polyfly has done some nifty rebranding of its hoverflies. The common drone fly — a poor choice of name for one of the world’s busiest pollinators — has been promoted to Queenfly, while its other offering, the large spotty-eyed dronefly, is sold as the Goldfly. Blowflies, linked in the public mind to death, decay and forensic examination of corpses, have a much bigger image problem. When the oriental latrine fly’s name comes up at a slick PR firm’s branding brainstorm, I’d like to be a fly on the wall.

More from Reset — An ongoing series exploring how the world is navigating the coronavirus pandemic, its consequences and the way forward.

Stephanie Pain writes about the natural world from an urban oasis in Brighton, UK.

This article originally appeared in Knowable Magazine, an independent journalistic endeavor from Annual Reviews.

The truth about lying

You can’t spot a liar just by looking — but psychologists are zeroing in on methods that might actually work

Police thought that 17-year-old Marty Tankleff seemed too calm after finding his mother stabbed to death and his father mortally bludgeoned in the family’s sprawling Long Island home. Authorities didn’t believe his claims of innocence, and he spent 17 years in prison for the murders.

Yet in another case, detectives thought that 16-year-old Jeffrey Deskovic seemed too distraught and too eager to help detectives after his high school classmate was found strangled. He, too, was judged to be lying and served nearly 16 years for the crime.

One man was not upset enough. The other was too upset. How can such opposite feelings both be telltale clues of hidden guilt?

They’re not, says psychologist Maria Hartwig, a deception researcher at John Jay College of Criminal Justice at the City University of New York. The men, both later exonerated, were victims of a pervasive misconception: that you can spot a liar by the way they act. Across cultures, people believe that behaviors such as averted gaze, fidgeting and stuttering betray deceivers.

In fact, researchers have found little evidence to support this belief despite decades of searching. “One of the problems we face as scholars of lying is that everybody thinks they know how lying works,” says Hartwig, who coauthored a study of nonverbal cues to lying in the Annual Review of Psychology. Such overconfidence has led to serious miscarriages of justice, as Tankleff and Deskovic know all too well. “The mistakes of lie detection are costly to society and people victimized by misjudgments,” says Hartwig. “The stakes are really high.”

Tough to tell

Psychologists have long known how hard it is to spot a liar. In 2003, psychologist Bella DePaulo, now affiliated with the University of California, Santa Barbara, and her colleagues combed through the scientific literature, gathering 116 experiments that compared people’s behavior when lying and when telling the truth. The studies assessed 102 possible nonverbal cues, including averted gaze, blinking, talking louder (a nonverbal cue because it does not depend on the words used), shrugging, shifting posture and movements of the head, hands, arms or legs. None proved reliable indicators of a liar, though a few were weakly correlated, such as dilated pupils and a tiny increase — undetectable to the human ear — in the pitch of the voice.

Three years later, DePaulo and psychologist Charles Bond of Texas Christian University reviewed 206 studies involving 24,483 observers judging the veracity of 6,651 communications by 4,435 individuals. Neither law enforcement experts nor student volunteers were able to pick true from false statements better than 54 percent of the time — just slightly above chance. In individual experiments, accuracy ranged from 31 to 73 percent, with the smaller studies varying more widely. “The impact of luck is apparent in small studies,” Bond says. “In studies of sufficient size, luck evens out.”

This size effect suggests that the greater accuracy reported in some of the experiments may just boil down to chance, says psychologist and applied data analyst Timothy Luke at the University of Gothenburg in Sweden. “If we haven’t found large effects by now,” he says, “it’s probably because they don’t exist .”

Police experts, however, have frequently made a different argument: that the experiments weren’t realistic enough. After all, they say, volunteers — mostly students — instructed to lie or tell the truth in psychology labs do not face the same consequences as criminal suspects in the interrogation room or on the witness stand. “The ‘guilty’ people had nothing at stake,” says Joseph Buckley, president of John E. Reid and Associates, which trains thousands of law enforcement officers each year in behavior-based lie detection. “It wasn’t real, consequential motivation.”

Samantha Mann, a psychologist at the University of Portsmouth, UK, thought that such police criticism had a point when she was drawn to deception research 20 years ago. To delve into the issue, she and colleague Aldert Vrij first went through hours of videotaped police interviews of a convicted serial killer and picked out three known truths and three known lies. Then Mann asked 65 English police officers to view the six statements and judge which were true, and which false. Since the interviews were in Dutch, the officers judged entirely on the basis of nonverbal cues.

The officers were correct 64 percent of the time — better than chance, but still not very accurate, she says. And the officers who did worst were those who said they relied on nonverbal stereotypes like “liars look away” or “liars fidget.” In fact, the killer maintained eye contact and did not fidget while deceiving. “This guy was clearly very nervous, no doubt,” Mann says, but he controlled his behavior to strategically counter the stereotypes.

In a later study, also by Mann and Vrij, 52 Dutch police officers did no better than chance at distinguishing true and false statements given by family members who’d murdered their relatives but denied it in anguished displays during televised press conferences used in the study. Notably, officers who performed the worst were those who felt that the emotional displays were genuine. But what did that signify? “If a husband killed his wife, he could be upset for all kinds of reasons, like remorse or getting caught,” says Mann. “Nonverbal behavior is so idiosyncratic. If you focus on the nonverbal behavior like emotions, you will trip up.”

Confirming these results on a large scale years later, Hartwig and Bond reviewed the literature for studies comparing people’s abilities to detect high- and low-stakes lies. They found no evidence that people were any better at detecting lies told by criminals or wrongly accused suspects in police investigations than those told by laboratory volunteers.

Something to hide

From serial killers to students fibbing in laboratory experiments, the lies in all these experiments were spoken. In a study published in 2019, Mann examined nonverbal deceit, such as when someone is trying to conceal illicit activity — a type of deception relevant to detecting bombers or smugglers. She recruited 52 university student volunteers and asked half of them to transport a laptop said to contain sensitive photographs on a ferry ride between two cities. The volunteers were told to try to blend into the crowd and not look “suspicious,” because people would be trying to identify them. The other half of the group were given a regular cell phone to transport, with no instructions to conceal what they were doing.

When Mann showed videos of the ferry rides to 104 other volunteers and asked them to pick out the “smugglers,” the spotters did no better than chance. In interviews afterward, the “smugglers” said they were nervous, but they consciously tried to act normal and control their nerves with tactics such as listening to music or using their phones.

Next, Mann raised the stakes. Half of a new group of 60 volunteers were given an envelope of Russian, Egyptian and Korean currency to conceal, while the other half didn’t “smuggle” anything. But this time, Mann sent two researchers onto the ferry to pace around and scrutinize the passengers, appearing to compare their faces to photos on a cell phone.

This time, 120 observers trying to pick out the “smugglers” on video guessed correctly just 39.2 percent of the time — well below chance. The reason, Mann says, is that the “smugglers” consciously made an effort to look normal, while the “innocent” control volunteers just acted naturally. Their surprise at the unexpected scrutiny looked to the observers like a sign of guilt.

The finding that deceivers can successfully hide nervousness fills in a missing piece in deception research, says psychologist Ronald Fisher of Florida International University, who trains FBI agents. “Not too many studies compare people’s internal emotions with what others notice,” he says. “The whole point is, liars do feel more nervous, but that’s an internal feeling as opposed to how they behave as observed by others.”

Studies like these have led researchers to largely abandon the hunt for nonverbal cues to deception. But are there other ways to spot a liar? Today, psychologists investigating deception are more likely to focus on verbal cues, and particularly on ways to magnify the differences between what liars and truth-tellers say.

For example, interviewers can strategically withhold evidence longer, allowing a suspect to speak more freely, which can lead liars into contradictions. In one experiment, Hartwig taught this technique to 41 police trainees, who then correctly identified liars about 85 percent of the time, as compared to 55 percent for another 41 recruits who had not yet received the training. “We are talking significant improvements in accuracy rates,” says Hartwig.

Another interviewing technique taps spatial memory by asking suspects and witnesses to sketch a scene related to a crime or alibi. Because this enhances recall, truth-tellers may report more detail. In a simulated spy mission study published by Mann and her colleagues last year, 122 participants met an “agent” in the school cafeteria, exchanged a code, then received a package. Afterward, participants instructed to tell the truth about what happened gave 76 percent more detail about experiences at the location during a sketching interview than those asked to cover up the code-package exchange . “When you sketch, you are reliving an event — so it aids memory,” says study coauthor Haneen Deeb, a psychologist at the University of Portsmouth.

The experiment was designed with input from UK police, who regularly use sketching interviews and work with psychology researchers as part of the nation’s switch to non-guilt-assumptive questioning, which officially replaced accusation-style interrogations in the 1980s and 1990s in that country after scandals involving wrongful conviction and abuse.

Slow to change

In the US, though, such science-based reforms have yet to make significant inroads among police and other security officials. The US Department of Homeland Security’s Transportation Security Administration, for example, still uses nonverbal deception clues to screen airport passengers for questioning. The agency’s secretive behavioral screening checklist instructs agents to look for supposed liars’ tells such as averted gaze — considered a sign of respect in some cultures — and prolonged stare, rapid blinking, complaining, whistling, exaggerated yawning, covering the mouth while speaking and excessive fidgeting or personal grooming. All have been thoroughly debunked by researchers.

With agents relying on such vague, contradictory grounds for suspicion, it’s perhaps not surprising that passengers lodged 2,251 formal complaints between 2015 and 2018 claiming that they’d been profiled based on nationality, race, ethnicity or other reasons. Congressional scrutiny of TSA airport screening methods goes back to 2013, when the US Government Accountability Office — an arm of Congress that audits, evaluates and advises on government programs — reviewed the scientific evidence for behavioral detection and found it lacking, recommending that the TSA limit funding and curtail its use. In response, the TSA eliminated the use of stand-alone behavior detection officers and reduced the checklist from 94 to 36 indicators, but retained many scientifically unsupported elements like heavy sweating.

In response to renewed Congressional scrutiny, the TSA in 2019 promised to improve staff supervision to reduce profiling. Still, the agency continues to see the value of behavioral screening. As a Homeland Security official told congressional investigators, “common sense” behavioral indicators are worth including in a “rational and defensible security program” even if they do not meet academic standards of scientific evidence. In a statement to Knowable, TSA media relations manager R. Carter Langston said that “TSA believes behavioral detection provides a critical and effective layer of security within the nation’s transportation system.” The TSA points to two separate behavioral detection successes in the last 11 years that prevented three passengers from boarding airplanes with explosive or incendiary devices.

But, says Mann, without knowing how many would-be terrorists slipped through security undetected, the success of such a program cannot be measured. And, in fact, in 2015 the acting head of the TSA was reassigned after Homeland Security undercover agents in an internal investigation successfully smuggled fake explosive devices and real weapons through airport security 95 percent of the time.

In 2019, Mann, Hartwig and 49 other university researchers published a review evaluating the evidence for behavioral analysis screening, concluding that law enforcement professionals should abandon this “fundamentally misguided” pseudoscience, which may “harm the life and liberty of individuals.”

Hartwig, meanwhile, has teamed with national security expert Mark Fallon, a former special agent with the US Naval Criminal Investigative Service and former Homeland Security assistant director, to create a new training curriculum for investigators that is more firmly based in science. “Progress has been slow,” Fallon says. But he hopes that future reforms may save people from the sort of unjust convictions that marred the lives of Jeffrey Deskovic and Marty Tankleff.

For Tankleff, stereotypes about liars have proved tenacious. In his years-long campaign to win exoneration and recently to practice law, the reserved, bookish man had to learn to show more feeling “to create a new narrative” of wronged innocence, says Lonnie Soury, a crisis manager who coached him in the effort. It worked, and Tankleff finally won admittance to the New York bar in 2020. Why was showing emotion so critical? “People,” says Soury, “are very biased.”

Editor’s note: This article was updated on March 25, 2021, to correct the last name of a crisis manager quoted in the story. Their name is Lonnie Soury, not Lonnie Stouffer.

Check out Reset — An ongoing series exploring how the world is navigating the coronavirus pandemic, its consequences and the way forward.

Jessica Seigel is an award-winning journalist and New York University adjunct journalism professor. Her work has appeared in the Washington Post, the New York Times, Salon and  National Geographic Traveler, on NPR, and more. Follow her on Twitter at @Jessicaseagull

This article originally appeared in Knowable Magazine, an independent journalistic endeavor from Annual Reviews. 

Twitter played a role in the collapse of Silicon Valley Bank – new research

Garnering lots of tweets can contribute to a bank’s woes. SOPA Images/LightRocket via Getty Images

Tony Cookson, University of Colorado Boulder and Christoph Schiller, Arizona State University

The Research Brief is a short take about interesting academic work.

The big idea

Prior to Silicon Valley Bank’s March 10, 2023, collapse, conversations on Twitter among investors about the bank spiked – helping fuel the SVB bank run. As we explain in our new working paper, “Social media as a bank run catalyst,” those tweets also destabilized other financial institutions with weak balance sheets.

The number of tweets mentioning “SIVB,” the bank’s stock ticker, increased sharply on March 9 around 9 a.m EST. That was roughly two and a half hours before tweets mentioning “SVB” or “Silicon Valley Bank,” which were part of a more general-interest discussion, began.

That spike in investor tweets coincided with the rapid drop in the bank’s stock price on March 9, which continued in after-hours trading and before the market opened the next morning. Trades in SVB’s stock were halted on March 10, the day the bank collapsed.

Together with several other colleagues, we grouped U.S. banks by the number of tweets posted about them and by their vulnerability to a potential bank run. To measure vulnerability, we multiplied losses the banks incurred due to the string of interest rate increases that began in March 2022 by the proportion of their deposits that were below the Federal Deposit Insurance Corp.‘s insurance limit of $250,000 per account.

We found that shares of banks with a lot of Twitter activity in January and February incurred much larger declines in March. This effect was stronger for the group of banks with the most vulnerability. One of them was First Republic Bank, which subsequently failed on May 1.

When we looked at what happened to the stocks of all the banks with vulnerable balance sheets from March 6 to March 13, the one-third of banks with the most tweets experienced declines in their share prices on average about twice as large as the others.

Why it matters

U.S. policymakers have acknowledged that social media may have played a role in Silicon Valley Bank’s demise.

Existing knowledge about bank runs comes mainly from banking distress during the Great Depression. Back then, word of mouth, media coverage and public signals, such as long lines outside of banks, spread panic among bank customers.

The breadth of the audience and the quick spread of ideas make social media distinct from newspapers and broadcast news since traditional media outlets mostly rely on one-way communication from official sources to the general public.

This will surely remain an important issue for banks, especially as other financial institutions face issues similar to those that felled SVB.

What other research is being done

A report on SVB’s failure that the Federal Reserve released on April 28 underscored many of the points we made in our paper. It highlights poor risk management by SVB in combination with a large fraction of depositors concentrated in the Silicon Valley startup community, who are often very active and highly connected on social media.

Another team of scholars, led by University of Pennsylvania finance professor Itamar Drechsler, determined that the recent growth of uninsured deposit accounts can destabilize banks.

As ongoing research by a team of researchers at Columbia University and the University of Chicago suggests, this risk may further be amplified by the rise of fully digital banks and mobile banking apps.

What is not known

Depositors who rapidy withdrew money from SVB also reportedly relied on private communication channels, such as group text messages, Slack and WhatsApp, as well as phone calls, to share their fears and concerns. But since there is no publicly available data, it is hard to find out what role those other less formal conversations played in precipitating the SVB bank run.

Tony Cookson, Associate Professor of Finance, University of Colorado Boulder and Christoph Schiller, Assistant Professor of Finance, Arizona State University

This article is republished from The Conversation under a Creative Commons license. 

Jerry Springer and the history of that [bleeping] bleep sound

Security guards separate guests on an episode of ‘The Jerry Springer Show’ titled ‘I am pregnant by my half-brother.’ Ralf-Finn Hestoft/Corbis via Getty Images

Matthew Jordan, Penn State

Since Jerry Springer’s death on April 27, 2023, writers have been working through the cultural significance of his eponymous daytime talk show.

For 27 years, Springer’s circus of sensationalism was a remarkably durable and bankable commodity. Helping to normalize outrageousness in culture, it taught content creators that shamelessness is a lucrative industry.

It’s been framed as a harbinger of “‘anything goes’ reality television” or “trash TV” and decried for setting a “new standard for tawdriness” and for providing audiences with the “guilty pleasure” of “chair-throwing.”

But as a media historian interested in the ways that sound structures our experience of TV shows and films, when I think of “The Jerry Springer Show,” I think of the sounds – the studio audience chanting “Jerry! Jerry!,” the boxing bell ringing when fists start flying, and the sonic dissonance between the heavy metal-tinged theme song and the soothing, paternal tone of its host.

But one of its most iconic sounds was added in post-production: the 1000 hertz censor bleep, which became more prevalent as the behavior on the show grew more profane.

An episode of the ‘The Jerry Springer Show’ features all the sonic hallmarks of the program – a chanting crowd, the slap of hand to skin and a cascade of bleeps.

The origins of bleeping

The history of broadcasters’ bleeping out profanity reveals a lot about our culture’s ongoing negotiation of a murky concept.

While the First Amendment protects political speech, it does not protect profanity, and in 1964 the Supreme Court gave the Federal Communications Commission the authority to police language in broadcasting.

Yet using sounds to mask offensive language predates the FCC and dates back to a 1921 radio speech on Newark, New Jersey’s WJZ by vaudeville actress Olga Petrova. Petrova was famous for her outspoken advocacy for feminism and birth control, and station managers worried that she might violate the 1873 Comstock Act, which prohibited the distribution of obscene materials, including information about contraception. So the radio engineers created a mechanism for masking her words with music from a phonograph when she dared speak her mind – and they ended up needing to use it several times.

By the time the FCC was established in 1927, studio engineers were regularly masking profanity, as the industry was always trying to stay one step ahead of the censors and stay in the good graces of advertisers. Further innovations, like the seven-second delay, aided the policing of live talk shows, allowing engineers to cover dirty words before they reached the audience’s ears.

Just exactly who deployed the bleep tone first is unclear, but engineers had long used the 1000 hertz sine wave tone to test equipment connections, so it was at their fingertips. By the mid-1960s, the bleep tone was heard everywhere, so much so that bleeping was used in FCC deliberations as a verb to define the practice of masking profanity.

Bleeping’s feedback loop

Yet by 1970, bleeping out words on TV news was viewed as a potential problem, with some regulators wondering if it unnecessarily tempered the way people actually behaved.

FCC chairman Dean Burch, for example, thought the commission should reconsider its use: “If a man stands up and calls me a dirty son of a bitch, I wonder whether we are giving the viewer the full flavor of the news if we quote him as saying, ‘You’re a dirty bleep, bleep, bleep.’”

Nonetheless, most broadcasters tended to err on the side of caution. Bleeping out profanity became so common in U.S. broadcasting that it inspired George Carlin to satirize the practice in his Seven Dirty Words You Can’t Say on TV monologue.

After the FCC came down on Pacifica Radio for broadcasting the bit, Pacifica sued the FCC and the case made it to the Supreme Court, which, in its decision, granted the FCC limited power to protect the public from profanity, especially during the daytime when kids might be listening.

Afterward, bleeping became more commonplace on radio and television.

Yet for audiences yearning for counterculture programming that seemed more real, focusing attention on profanity by bleeping it created a feedback loop that made cursing – and the rebels who did it – more appealing to audiences, piquing their interest about what the bleep concealed.

At the same time, networks pushing for deregulation wanted to show that they could self-censor and that FCC oversight wasn’t necessary. By the early 1980s, a new radio format based on shocking public sensibilities, the “shock jock,” had emerged. Radio performers like Don Imus and Howard Stern found that audiences would tune in to hear profane behavior and would return daily to see just how far the performers would go.

Industry programming followed the ratings.

Springer’s brand of profane realism

By the time Springer’s show began in 1991, a paradoxical mix of deregulation and self-censoring had settled over the industry, producing edgy shows with lots of bleeps.

Audiences experienced bleeped performances as more authentic. Provocateurs like Madonna knew cursing drew attention, and she has repeatedly used the self-promotional technique ever since her infamous spot on “The Arsenio Hall Show” in 1990, when she talked about giving good [bleep]. It was the highest-rated Arsenio show ever.

Springer quickly learned that booking guests who required bleeps boosted ratings.

Jerry Springer saw the show’s violence and profanity as ‘the price of reality.’ But the ratings boost certainly didn’t hurt, either. Ralf-Finn Hestoft/Corbis via Getty Images

As the show found its niche, it shifted so that it was no longer Springer confronting racists, deviants or polygamists. Instead, guests involved in relationship betrayals or with simmering resentments would confront one another. As the frequency of the bleeps and fights increased, the ratings began to soar. By 1997, it often matched “The Oprah Winfrey Show” at the top of the ratings leaderboard.

In one “Final Thoughts” segment in 1995, Springer defended his fight-inducing exploitation of raw emotion, calling it “the price of reality, this loss of civility, as we take entertainment to the edge of real life and real people.” The bleeping became central to the aesthetic, a Pavlovian signal to audiences at home that the explosive behavior was “real.”

In fact, media researchers have shown that bleeping words actually draws attention to them and that audiences perceive the frequency of profanity to be higher when words are bleeped.

That [bleeping] reality TV sound

By the turn of the century, the show’s sound mix was set, with audiences chanting “Jerry! Jerry!” whenever the bleeps started flying. By the show’s third decade, in episodes like “You slept with my stripper sister,” everyone seemed to be in on the pro wrestling nature of the spectacle.

In case they weren’t, the bleep sound was often accompanied by a boxing bell, cuing everyone that [bleep] was getting real.

Toward the end of the show’s run, the meaning of the bleep sound became more comedic. Where audience reaction shots once revealed them gasping, now they were laughing.

The bleep sound, a standard effect heard across the burgeoning reality TV format, had great comedic impact in shows like “The Osbournes,” where Ozzy would stumble around muttering profanity that had to be bleeped. It’s telling that the bleep became a sound effect used in scripted comedy as well, exploited in shows like “Arrested Development” and “South Park” for maximum effect.

Today, when broadcasters want to censor profanity on live shows, like they did during the Oscars after Will Smith slapped Chris Rock, they tend to mute the sound rather than bleep over it.

Nonetheless, even if what counts as profanity keeps shifting, the meaning of the bleep sound is universally understood: It means profanity is happening. And like the definition of obscenity given by Supreme Court Justice Potter Stewart way back in 1964, people know it when they hear it.

Matthew Jordan, Associate Professor of Media Studies, Penn State

This article is republished from The Conversation under a Creative Commons license.

AI is exciting – and an ethical minefield: 4 essential reads on the risks and concerns about this technology

Who’s in control? John Lund/Stone via Getty Images

Molly Jackson, The Conversation

If you’re like me, you’ve spent a lot of time over the past few months trying to figure out what this AI thing is all about. Large-language models, generative AI, algorithmic bias – it’s a lot for the less tech-savvy of us to sort out, trying to make sense of the myriad headlines about artificial intelligence swirling about.

But understanding how AI works is just part of the dilemma. As a society, we’re also confronting concerns about its social, psychological and ethical effects. Here we spotlight articles about the deeper questions the AI revolution raises about bias and inequality, the learning process, its impact on jobs, and even the artistic process.

1. Ethical debt

When a company rushes software to market, it often accrues “technical debt”: the cost of having to fix bugs after a program is released, instead of ironing them out beforehand.

There are examples of this in AI as companies race ahead to compete with each other. More alarming, though, is “ethical debt,” when development teams haven’t considered possible social or ethical harms – how AI could replace human jobs, for example, or when algorithms end up reinforcing biases.

Casey Fiesler, a technology ethics expert at the University of Colorado Boulder, wrote that she’s “a technology optimist who thinks and prepares like a pessimist”: someone who puts in time speculating about what might go wrong.

That kind of speculation is an especially useful skill for technologists trying to envision consequences that might not impact them, Fiesler explained, but that could hurt “marginalized groups that are underrepresented” in tech fields. When it comes to ethical debt, she noted, “the people who incur it are rarely the people who pay for it in the end.”

2. Is anybody there?

AI programs’ abilities can give the impression that they are sentient, but they’re not, explained Nir Eisikovits, director of the Applied Ethics Center at the University of Massachusetts Boston. “ChatGPT and similar technologies are sophisticated sentence completion applications – nothing more, nothing less,” he wrote.

But saying AI isn’t conscious doesn’t mean it’s harmless.

“To me,” Eisikovits explained, “the pressing question is not whether machines are sentient but why it is so easy for us to imagine that they are.” Humans easily project human features onto just about anything, including technology. That tendency to anthropomorphize “points to real risks of psychological entanglement with technology,” according to Eisikovits, who studies AI’s impact on how people understand themselves.

People give names to boats and cars – and can get attached to AI, too. Yuichiro Chino/Moment via Getty Images

Considering how many people talk to their pets and cars, it shouldn’t be a surprise that chatbots can come to mean so much to people who engage with them. The next steps, though, are “strong guardrails” to prevent programs from taking advantage of that emotional connection.

3. Putting pen to paper

From the start, ChatGPT fueled parents’ and teachers’ fears about cheating. How could educators – or college admissions officers, for that matter – figure out if an essay was written by a human or a chatbot?

But AI sparks more fundamental questions about writing, according to Naomi Baron, an American University linguist who studies technology’s effects on language. AI’s potential threat to writing isn’t just about honesty, but about the ability to think itself.

American writer Flannery O'Connor sits with a copy of her novel ‘Wise Blood,’ published in 1952. Apic/Hulton Archive via Getty Images

Baron pointed to novelist Flannery O'Connor’s remark that “I write because I don’t know what I think until I read what I say.” In other words, writing isn’t just a way to put your thoughts on paper; it’s a process to help sort out your thoughts in the first place.

AI text generation can be a handy tool, Baron wrote, but “there’s a slippery slope between collaboration and encroachment.” As we wade into a world of more and more AI, it’s key to remember that “crafting written work should be a journey, not just a destination.”

4. The value of art

Generative AI programs don’t just produce text, but also complex images – which have even captured a prize or two. In theory, allowing AI to do nitty-gritty execution might free up human artists’ big-picture creativity.

Not so fast, said Eisikovits and Alec Stubbs, who is also a philosopher at the University of Massachusetts Boston. The finished object viewers appreciate is just part of the process we call “art.” For creator and appreciator alike, what makes art valuable is “the work of making something real and working through its details”: the struggle to turn ideas into something we can see.

Editor’s note: This story is a roundup of articles from The Conversation’s archives.

Molly Jackson, Religion and Ethics Editor, The Conversation

This article is republished from The Conversation under a Creative Commons license.

Keeping time with zircons

Crystals of the mineral zircon are rugged enough to survive the most violent geologic events. Impurities within them provide a time capsule of planetary history.

By Cypress Hansen

Diamonds may be the hardest of gemstones, but it’s zircons that last forever. So durable are these birthstones of December that they represent Earth’s oldest known material: Some zircons from Australia date back more than 4 billion years.

But zircons aren’t just old. Much like tree rings, they can record time, revealing the ages of the rocks surrounding them and the geologic processes they have witnessed. Thanks to zircons, researchers can tell the origin stories of planets, infer when continents rose from the oceans, and perhaps even discover precious minerals beneath the Earth’s surface.

“The amount that we know about the Earth without the help of zircons is very, very small,” says Jesse Reimink, a geologist who studies the crystals at Pennsylvania State University.

The mineral zircon forms when the elements zirconium, silicon and oxygen crystallize in magma or metamorphic rock. Over time, repeated heating and cooling adds outer layers to the crystal, like successive coats of paint. Atoms of a handful of elements, such as uranium, are similar enough to zirconium atoms that they can take their place within the crystal structure. If these atoms are radioactive, they will slowly convert to another element — such as lead — through the predictable process of radioactive decay.

When this happens, the crystal becomes a clock. By blasting zircon crystals with lasers or dissolving them with acid and then measuring the uranium-to-lead ratios, for example, scientists can estimate the timing of ancient geological events with impressive precision.

Zircon “is the perfect mineral for the uranium-lead decay system,” says Reimink, “and the uranium-lead decay system is like God’s gift to geochronology.”

And because zircons are extremely resistant to melting, cracking or eroding away, they allow researchers to date some of the oldest events on the planet.

“Zircon research is the horizon on which we are able to make discoveries about the early Earth,” says geochemist Beth Ann Bell of UCLA. “It’s part of trying to understand where we come from.”

Zircons are roughly the size of a grain of sand and researchers often have to collect, crush and sift through several kilograms of rock to get a good-sized sample. But with improved laser technology and more sensitive analytic instruments, zircon dating is getting easier and more precise — meaning scientists can extract more information from fewer crystals. “The field is evolving very rapidly,” says Martin Bizzarro, a planetary scientist at the University of Copenhagen. “People are pushing the boundaries to analyze smaller and smaller samples with the highest precision.”

Here’s some of what scientists are learning from these tiny timepieces.

The births of planets

In 2011, a Martian meteorite nicknamed Black Beauty was discovered in the Moroccan desert. Zircons within the meteorite hold clues to the Red Planet’s birth — and to the origins of its water.

Dating the zircons revealed an ancient age of 4.47 billion years, Bizzarro and colleagues found, and the crystals’ composition suggests that Mars formed within the first 20 million years of our solar system’s existence — a surprisingly quick formation. Back then, plenty of boulders, ice chunks and water vapor — the building blocks of planets — were still circling the newborn sun, waiting to be sucked in by the gravity of growing planets.

Further analyses of bits of the Martian meteorite, including ancient fragments of the planet’s crust, suggest that water may have been present on the Martian surface in the first 80 million years of the planet’s evolution. Scientists have long debated whether water has been present on Mars (and Earth) from the very beginning, or if it arrived later from icy asteroid bombardment. If water emerges on other planets when they form quickly, then “there should be plenty of water worlds in the galaxy and potentially habitable planets,” Bizzarro says.

The rise of continents

Some scientists believe that Earth was completely covered in water before the first continents emerged around 3 billion years ago. How quickly the Earth’s landmasses rose from the seas, however, has remained a mystery. Zircons deposited in ancient riverbeds and oceans have recently helped geologists chronicle this massive event, lending insights to the evolution of life on land and to climate regulation.

Zircons, carrying age signatures of their original locations, are released into rivers by erosion, deposited downstream and compacted into sedimentary rocks. Rocks that contain a wide range of zircon ages probably came from a large number of eroded rock sources, and thus a larger watershed. To determine the size of ancient watersheds, and thus the growth of early continents, Reimink analyzed zircon age data from more than 4,200 rock samples from around the world. The results, published in Earth and Planetary Science Letters in 2021, suggest that the continents took 500 million years to reach their current heights once they began rising from the oceans 2.8 billion years ago.

This finding can help scientists understand all kinds of things, such as when the Earth’s oceans began absorbing huge amounts of volcanic gases including carbon dioxide from the atmosphere, a process that altered the climate and shaped Earth’s ability to sustain life.

The earliest signs of life

A 4.1-billion-year-old crystal discovered in Jack Hills, Australia, harbored what could be some of the earliest evidence of life on Earth. If true, the find suggests that life began fairly quickly after the formation of the planet some 4.54 billion years ago.

The zircon had specks of pure carbon, also known as graphite, preserved within its structure. These inclusions contained a common form of carbon known as carbon-12, along with unusually low levels of its heavier counterpart, carbon-13. Plants and algae preferentially store the lighter carbon-12 during photosynthesis, so researchers use carbon ratios to distinguish fossils of once-living organisms from ordinary rocks.

The lighter material in the inclusions, says Bell, “is consistent with what we see in life today.” Of course, pinning down when life emerged is tricky and often controversial: Very old fossils are scarce and scientists don’t always agree on how to interpret them. Because Bell and her colleagues, who reported the find in the Proceedings of the National Academy of Sciences in 2015, found only one graphite-flecked zircon pristine enough to definitively rule out contamination, there is skepticism. “But people haven’t really been looking for graphite in zircons for very long,” says Bell. Additional research — and zircons — are needed to add certainty.

The threat of volcanoes

Supervolcanoes can present serious threats, and researchers are increasingly looking to zircons to help predict the next flare-up. Zircons spewed out in prior eruptions can shed light on what’s going on beneath the surface in the lead-up to a blowout, such as how long it takes for magma to build up before breaching the surface, says volcanologist Fidel Costa of the Earth Observatory of Singapore.

In one such instance, an international team of scientists analyzed zircons that were erupted from the Nevado de Toluca volcano over the last 1.5 million years. The analysis, published in November in Nature Communications, suggests that only a fraction of the dormant volcano’s magma has been erupted, and if the magma begins to move again, the volcano could erupt within a human lifetime.

Such zircon-informed timescales, says Costa, who recently outlined the state of geochronology of volcanic rocks in the 2020 Annual Review of Earth and Planetary Sciences, “give us an indication of how much time we have to get ready.”

The lure of precious metals

Exploring for minerals deep in the ground is no easy task, but zircons in rocks near the surface might lead prospectors to lucrative mining spots. In a case study, researchers in southern British Columbia confirmed that local zircons held clues to the copper deposits hidden below. The zircons evaluated contained high levels of the element europium, an indicator that the region’s rocks formed from water-rich magma — a prerequisite for the formation of a particular kind of copper deposit, researchers reported in Economic Geology in January.

Many economically valuable minerals, such as gold, form in the same regions of molten, rocky mush beneath the Earth’s surface that zircons originate in. The new research suggests that collecting zircons from rocks at the surface may be a fruitful way to learn whether the surrounding rockbeds have the right chemistry or age to be fertile grounds for desired metals.

Zircons are so useful and scientists are so enthusiastic about them that relevant geologic information in non-zircon rock samples is sometimes ignored, notes Scott Bryan of the Queensland University of Technology in Brisbane, Australia. (Bryan published a reminder of zircons’ limitations in 2018 in Earth-Science Reviews.) Still, he adds, while including other analyses surely provides a more holistic view of Earth’s distant past, zircon dating is the best tool going for geochronology. Zircons convey so much about the past, present and future that they’re the closest thing scientists have to a crystal ball.

Check out Reset — An ongoing series exploring how the world is navigating the coronavirus pandemic, its consequences and the way forward.

Cypress Hansen is Knowable Magazine’s writing intern. She’s never been impressed with diamonds, and might just ask for a zircon in her wedding ring. Follow Cypress  @pollenplankton.

This article originally appeared in Knowable Magazine, an independent journalistic endeavor from Annual Reviews. 

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Sudan’s plunge into chaos has geopolitical implications near and far – including for US strategic goals

Jordanians being evacuated from Sudan amid fighting between two factions. AP Photo/Raad Adayleh

Christopher Tounsel, University of Washington

The sight of diplomats fleeing Sudan amid chaotic scenes reflects the gravity of the situation, but also the extent of international interest in the strife-torn nation.

Days into fighting that has left at least 400 people dead, governments from across the Middle East, Europe, Asia and the Americas evacuated nationals – teachers, students and workers, as well as embassy staff – from the capital, Khartoum.

Of course, expat employees are to be found in all countries. But as a scholar of Sudanese history, it is difficult to ignore the fact that, in the words of one analyst, everyone wants “a chunk of Sudan.” While a 2019 coup ended the brutal dictatorship of Omar al-Bashir, the years since have not given way to democracy. Rather, it has led to a period in which various overseas governments have sought to capitalize on the transition of power and Sudan’s strategic importance and mineral wealth.

And while a descent into all-out civil war would be devastating for Sudan, it would also create ripples that would be felt throughout the geopolitical world.

Where things stand

The evacuation of foreign nations followed the eruption of violence between the Sudanese military, led by the country’s leader, Gen. Abdel Fattah al-Burhan, and the paramilitary Rapid Support Forces, led by Gen. Mohamed Hamdan Dagalo, generally known by the name Hemedti.

The two men jointly ran the government but now find themselves deadlocked in a power struggle. On April 25, 2023, Saudi Arabia and the U.S. brokered a three-day ceasefire. Despite sporadic fighting, that ceasefire was later extended.

Efforts of international governments to broker peace may hint not only at a desire to halt the bloodshed, but also a desire to limit the fallout that the situation will have for world politics.

Sudan’s regional, economic and strategic importance

Sudan is located at a critical nexus, geographically. It borders Egypt and Libya in North Africa, Ethiopia and Eritrea in the Horn of Africa, the East African nation of South Sudan, and Central Africa’s Chad and the Central African Republic.

Sudan is the site where the White and Blue Nile Rivers merge to form the main Nile and is home to more than 60% of the Nile River Basin. Safe management of the Nile’s water is crucial for stability of the region. Northern neighbor Egypt is 90% dependent on the river for its water supply, while Ethiopia to the east is looking to double the country’s electricity generation through the construction of the Grand Ethiopian Renaissance Dam.

The project has been a source of contention, though – Ethiopia began filling the dam in 2020-2021 without an agreement with Egypt, and last year Egypt protested Ethiopia’s planned third filling of the dam to the U.N. Security Council. The United Nations has called on the three nations to negotiate a “mutually beneficial” agreement over the Nile’s management – something that will be difficult should Sudan fall into a prolonged period of instability.

Sudan also has a strategic location on the Red Sea, a body of water that approximately 10% of global trade passes through, with the Suez Canal connecting Asian and European markets.

And then there are Sudan’s immense mineral resources. The nation is Africa’s third-largest producer of gold, has major oil reserves and produces over 80% of the world’s gum arabic – a component of food additives, paint and cosmetics.

Sudanese gold, Russia’s war

As a result of this strategic and economic importance, Sudan has attracted willing international partners. Gulf oil states Saudi Arabia and the United Arab Emirates, for example, saw Bashir’s ouster as a chance to stabilize the region and invest in everything from agricultural projects to Red Sea ports.

Sudan’s leaders have seemingly been none too picky about who they partner with. While much of the international community shunned and sanctioned Russia after the 2022 invasion of Ukraine, Sudan provided Moscow with an economic lifeline through its gold reserves.

Russia’s interest in Sudan’s gold dates back to 2017, when after a meeting between Bashir and Russian President Vladimir Putin, the two countries established the Meroe Gold corporation – a subsidiary of the Wagner Group network of mercenaries.

Since the 2019 coup, Moscow has increasingly aligned itself with Hemedti, as the RSF leader sought to control more and more of the country’s richest gold mines. In July 2022, Sudanese sources told CNN that at least 16 Russian gold smuggling flights had embarked from Sudan over the previous year and a half.

The Wagner Group’s involvement in Sudanese gold extraction and its role in supplying fighters in Ukraine have prompted many observers to suggest that Sudanese gold is being used to finance Moscow’s war.

In return, Russia has provided political and military assistance to Sudan’s paramilitary leadership. According to U.S. officials, the Wagner Group has offered weaponry, including surface-to-air missiles, to the RSF.

Hemedti is not alone in currying Russian support. Theodore Murphy, Africa director at the European Council of Foreign Relations, has suggested that the RSF leader’s now-rival, Burhan, would also be open to working with Moscow.

China a winner in Sudan scramble

China also has considerable interests in Sudan as part of its “Belt and Road” global infrastructure initiative. From 2011 to 2018, Beijing granted Sudan an estimated US$143 million in loans and has invested in projects such as the construction of Sudanese oil pipelines, Nile bridges, textile mills and railway lines.

Indeed, China was one of the main investors to Sudan during the rule of Bashir and one of the few countries to supply the regime with weapons.

China relies on Africa’s mineral resources to meet its own expanding industrial needs. China-Sudan mining cooperation dates back to the 1970s, and over 20 Chinese enterprises have operated in Sudanese mining with a total investment of over $100 million.

However, this relationship is not entirely one-way. Sudan exported $780 million worth of products to China in 2021 and in the previous quarter-century increased its exports to China at an annual rate of 10.6%. Indeed, China is Sudan’s second-largest trading partner after the UAE, and the African nation’s biggest supplier of goods.

Although the U.S. revoked long-standing sanctions against Sudan in 2017, allowing for American companies to pursue business interests in Sudan, Washington is still playing catch-up with China.

Concerns of contagion

The United States’ strategic interest in the Sudanese crisis can be considered through the lens of its opposition to Russia’s war in Ukraine and concern over regional contagion – that is, the spread of instability.

Sudan’s potential to prop up Moscow’s war effort would make Western leaders wary of the RSF gaining an upper hand in the current fighting; the paramilitary group could reward Russia’s friendship with Sudanese gold. But with an apparent willingness of both sides of the current fighting to exploit the country’s gold mines in return for Moscow’s military assistance, a better outcome for the West – and indeed the Sudanese people – would be a transition away from military rule altogether.

Of perhaps more concern to Washington is the impact of an unstable Sudan on the region. In recent years, the U.S. has benefited from a warming relationship with Sudan’s leaders, especially through counterterrorism cooperation. The Biden administration will surely be fearful of Sudan’s instability providing the kind of conditions in which terrorist groups, such as al-Shabaab, may thrive. or that the situation could trigger a refugee crisis on Sudan’s borders, especially in Ethiopia and South Sudan – countries that are already struggling to keep fragile peace deals in place.

While the people of Sudan have the most to lose should the current fighting descend into civil war, the geopolitical significance of the country means millions in the surrounding regions – and indeed around the world – also stand to be impacted.

Christopher Tounsel, Associate Professor of History, University of Washington

This article is republished from The Conversation under a Creative Commons license.