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Empirics and Psychology: Eight of the World’s Top Young Economists Discuss Where Their Field Is Going
The past few years have been tough on economics and economists. In a searing indictment written one year after the collapse of Lehman Brothers, Paul Krugman concluded that
the central cause of the profession’s failure was the desire for an all-encompassing, intellectually elegant approach that also gave economists a chance to show off their mathematical prowess. Unfortunately, this romanticized and sanitized vision of the economy led most economists to ignore all the things that can go wrong. They turned a blind eye to the limitations of human rationality…to the problems of institutions that run amok; to the imperfections of markets…and to the dangers created when regulators don’t believe in regulation.
Last August, Graeme Maxton published a book arguing that “modern economics has failed us,” and this April, the New York Times hosted a roundtable “about how the teaching of economics should change in light of the financial crisis.”
This soul-searching has led to the establishment of organizations such as the Institute for New Economic Thinking and invigorated discussions about alternative metrics for gauging countries’ welfare (last July, in fact, the UN General Assembly adopted a resolution asserting that “the gross domestic product indicator by nature was not designed to and does not adequately reflect the happiness and well-being of people in a country”).
To get the pulse of a field in flux, I asked eight of the world’s top young economists to identify the biggest unanswered questions in economics and predict what breakthroughs will define it a decade or two hence.
Stanford University; 39
Why are developing countries poor? In terms of impact on mankind globally, this strikes me as probably the biggest and most important current economic question. I think the answer is complex and linked to a combination of factors around history, geography, luck, etc. I am personally working on management practices: people in developing countries are poor because wages are low, and wages are low because firms are very unproductive, and firms seem to be unproductive in large part because of bad management. An Indian worker makes in one week what an average U.S. worker makes in a half a day. One big factor seems to be that factories in India are frankly very badly managed: equipment is not looked after, materials are wasted, theft is common because inventory is not monitored, defects keep occurring, etc. In a recent project with the World Bank, we found in randomized experiments that giving simple management advice to Indian factories increased productivity by 20%, and I suspect that a number like 200% would be possible in the longer run.
Developed countries’ biggest question now is probably: how do we restart growth? There are a lot of issues here around innovation, curbing entitlement spending, etc. The area I know best is the short-run side of this, controlling policy uncertainty. A big factor that politicians and the media are pushing heavily right now is that growth is getting crushed by how policy has induced uncertainty. Basically, firms and consumers in the U.S. and Europe are holding back from spending until they know what is going to happen with taxes, spending, and (to a lesser extent) regulations over the next year or so. In the U.S., we have the November 2012 election generating a massive cloud of policy uncertainty, and in Europe, a rolling wave of elections and collapsing governments.
I do not think that any one single breakthrough will happen. The progress is likely to be heavily empirical—simply because more and more data is becoming available, and it is easy to analyze with fast computers (so empirics is now advancing faster than theory)—and spread across many hundreds of topics. So economics has gone from Victorian science, where one genius in his shed could invent the steam engine over the weekend, to industrial science, where innovation comes in thousands of tiny steps made by dozens of research teams.
Harvard University; 32
Many economists are concerned with two broad questions: how can we increase the rate of economic growth and overall well-being, and how can we reduce the rate of poverty? Countless policies—taxation, education, healthcare, etc.—have been implemented in an effort to achieve those objectives. One of our biggest challenges is to distill each policy’s unique impact so that we can understand which ones actually work and which ones do not.
The traditional state of economics is captured by the joke about ten economists, each of whom has a different theory of how the world works, none of which is directly tested or verified. Looking ahead, I am most excited about the prospect of having clear, evidence-based answers on which policies have the most beneficial economic impacts. I am especially optimistic that the expansion of access to large administrative datasets, such as earnings data from social-security records or student-achievement data from school districts, will yield sharp, quasi-experimental evidence that allows us to test theories and estimate key parameters of economic models. While theory will play an important role in guiding this research, its assumptions and conclusions will increasingly be empirically founded.
Within this broad area, I plan to pursue research on two sets of projects over the next few years. The first will try to identify the determinants of intergenerational mobility, with an eye towards finding policies that increase equality of opportunity. Should we be focusing on increasing access to higher education? Changing the structure of elementary schooling? Revamping the tax code? A second set of projects will explore the implications of behavioral economics for policymaking. Although we have accumulated considerable evidence showing that people do not always behave rationally, we do not have as good a sense of how they actually do behave and what this means for policy. I hope to make progress on this front, focusing on how we can design cost-effective policies that encourage people to save adequately for their retirement—to give just one example.
Federal Reserve Bank of New York; 37
I think the recent world economic crisis has firmly put back on the map basic macroeconomics: that is, the study of traditional questions, such as how to use monetary and fiscal policy to eliminate unemployment and control inflation. It was actually becoming quite unfashionable within economics to study these types of questions, even though they remain unanswered to a large extent. People even graduated with PhDs in economics with little idea about what role, if any, the government plays in stabilizing business cycles, the role of regulations, and so on. Instead, it was becoming increasingly fashionable to tackle smaller but more manageable questions for which data is rich and answers clear.
My guess, therefore, is that if one looks back 20 years from now, one will notice that a shift occurred towards studying the basic, big-picture, policy-relevant questions of macroeconomics—e.g., optimal currency areas, bank runs, fads and herding in financial markets, and automatic stabilizers—that have the power to change the course of history. I think there have been two comparable events that shaped the field in this way. As a discipline, macroeconomics was born in response to the Great Depression, giving rise to Keynesianism; the rational-expectations revolution in macroeconomics was born in response to the great inflation on the 1970s.
Perhaps somewhat under the radar, the past two decades have witnessed the integration of the macroeconomics that came out of the 1970s and 1980s with basic Keynesian models developed in the wake of the Great Depression. I suspect that the current crisis will accelerate that development, with models integrating financial frictions that were clearly central to its emergence.
New York University; 40
The most central open question in economic theory, as I see it, is how to model realistic economic agents. Traditionally, economists have relied on the rational-actor model, but it is clear that it is just a rough caricature. It has been greatly enriched by behavioral economics in the past 30 years. Still, we are far from a unified, versatile, believable alternative to the rational-actor model. I am hopeful, though, that this might be overcome—in part because of progress in the sister disciplines (psychology and neuroscience) and basic modeling, and also because empirical anomalies are forcing the economic profession to be more open-minded. Contributions by computer scientists and physicists will help inject new perspectives into economics.
The largest concrete questions in economics are, arguably, how to increase growth—particularly in developing countries—and how to avoid economic disasters and financial crises.
Progress in understanding limited rationality will lead to progress on answering the concrete questions. Low levels of growth are in part due to misapplied cognitive heuristics that lead people to be timid, inert, and gullible. Regarding disasters, during the unfolding of the crisis, traditional macro-financial factors (bank runs, deleveraging, etc.) have arguably been more important than behavioral factors. However, behavioral elements seem to have been paramount in the buildup of the current crisis (in particular, the neglect of tail events by financial actors and by the architects of the euro), as perhaps they are in most crises. The modeling of agents with bounded rationality will help us build economic models (in particular, macroeconomic and financial models) and institutions that better take into account the limitations of human reason.
Harvard University; 40
All countries wish to pursue sustainable growth without large boom-bust episodes. How exactly one accomplishes this remains a challenge that has been made starker by the current crisis. In an increasingly globalized world, the search for answers will necessarily require a much deeper understanding of three areas that interest me. One, we need a better understanding of the interlinkages across countries in trade, finance, and macroeconomic policy. The crisis in the Euro area brings this to the forefront. The complex ties across the member countries via trade, via banks, and through a shared monetary policy are central factors behind the ongoing sovereign debt, banking, and growth crises in the region. While trade interactions are better understood, financial flows remain a challenge.
Two, understanding the global economy requires a greater appreciation of the differences across economies. In the past, research mainly focused on analyzing interactions across economies that were similar in terms of their stages of development and their economic institutions. The most interesting questions today, however, concern interactions between developed economies and fast-growing developing economies, and between countries with diverse economic institutions. Questions on so-called global imbalances, currency wars, and capital controls have to do with interactions across diverse countries.
Three, understanding asymmetries in the international monetary system—with the prominence of the dollar in trade and financial transactions—will be crucial to understanding the propagation of shocks across economies. In my research, I find that international prices, regardless of what currency they are set in, respond very little to exchange rates. Since the dollar is the predominant trade currency, this implies that exchange-rate movements have a much smaller impact on U.S. import price inflation than they do on inflation in other countries.
Addressing these areas will require breakthroughs in theory and empirical work, with more micro-level datasets on prices, trade, and capital flows being brought to bear.
George Mason University; 32
My candidate for the biggest unanswered question in economics is the status of the rationality postulate: the decision to analyze actors as utility maximizers with consistent preferences. If we view economics as an “engine” for understanding the world, the rationality postulate was that engine in nearly all of economics until quite recently. The rise of behavioral economics has challenged the usefulness and, in a more subtle but radical way, the legitimacy of the rationality engine. While only a minority of economists would describe themselves as “behavioralists,” behavioralism has affected many more by influencing the kinds of questions economists consider important to ask and influencing the kinds of answers to those questions they consider illuminating. These influences have the potential to profoundly affect the way economics is done, and thus what economics is able offer our understanding of the world.
At the moment, most behavioralism avers merely to “fine tune” the rationality engine rather than replace it. But even such tuning can have and, as I intimated a moment ago, I think has already had, a noticeable impact on how a growing number of economists and those following them interpret society. To the extent that economists’ view of, say, markets as reflecting rational vs. irrational systems—or, more specifically, their interpretation of economic crises as the product of markets responding rationally to poor policy vs. the product of endemic irrational decision-making—either directly or indirectly influences public policy, the way in which the status of the rationality postulate is resolved will not merely shape what economists are doing. It will shape the kind of society we inhabit.
University of Chicago; 27
In his famous 1945 article, “The Use of Knowledge in Society,” F. A. Hayek argued that despite their inequity and inefficiency, free markets were necessary in order to allow the incorporation of information held by dispersed individuals into social decisions. No central planner could hope to collect and process all the information necessary for social decisions; only markets allowed and provided the incentives for disaggregated information processing. Yet, increasingly, information technology is leading individuals to delegate their most “private” decisions to automated processing systems. Choices of movies, one of the last realms of taste one would have guessed could be delegated to centralized expertise, are increasingly shaped by services like Netflix’s recommender system. While these information systems are mostly nongovernmental, they are sufficiently centralized that it is increasingly hard to see how dispersed information poses the challenge it once did to centralized planning.
Information technology thus fundamentally challenges the standard foundations of the market economy. For many years to come, economists will increasingly have to struggle with this challenge. Some will harness the power of the data and computational power provided by information technology to provide increasingly precise and accurate prescriptions for economic planning. Others, who value the libertarian tradition that has often been associated with economics, will be forced to articulate other arguments, perhaps based on privacy, that are not susceptible to erosion by the increasing power of centralized computation.
University of Pennsylvania; 39
Economics is in the midst of a massive and radical change. It used to be that we had little data, and no computing power, so the role of economic theory was to “fill in” for where facts were missing. Today, every interaction we have in our lives leaves behind a trail of data. Whatever question you are interested in answering, the data to analyze it exists on someone’s hard drive, somewhere. This background informs how I think about the future of economics.
Specifically, the tools of economics will continue to evolve and become more empirical. Economic theory will become a tool we use to structure our investigation of the data. Equally, economics is not the only social science engaged in this race: our friends in political science and sociology use similar tools; computer scientists are grappling with “big data” and machine learning; and statisticians are developing new tools. Whichever field adapts best will win. I think it will be economics. And so economists will continue to broaden the substantive areas we study. Since Gary Becker, we have been comfortable looking beyond the purely pecuniary domain, and I expect this trend towards cross-disciplinary work to continue.
Photo Credit: JFunk/Shutterstock.com
"Deepfakes" and "cheap fakes" are becoming strikingly convincing — even ones generated on freely available apps.
- A writer named Magdalene Visaggio recently used FaceApp and Airbrush to generate convincing portraits of early U.S. presidents.
- "Deepfake" technology has improved drastically in recent years, and some countries are already experiencing how it can weaponized for political purposes.
- It's currently unknown whether it'll be possible to develop technology that can quickly and accurately determine whether a given video is real or fake.
After former U.S. President William Henry Harrison delivered his inaugural speech on March 4, 1841, he posed for a daguerreotype, the first widely available photographic technology. It became the first photo taken of a sitting American president.
As for the eight presidents before Harrison, history can see them only through artistic renderings. (The exception is a handful of surviving daguerreotypes of John Quincy Adams, taken after he left office. In his diary, Adams described them as "hideous" and "too true to the original.")
But a recent project offers a glimpse of what early presidents might've looked like if photographed through modern cameras. Using FaceApp and Airbrush, Magdalene Visaggio, author of books such as "Eternity Girl" and "Kim & Kim," generated a collection of convincing portraits of the nation's first presidents, from George Washington to Ulysses S. Grant.
Modern Presidents George Washington https://t.co/CURJQB0kap— Magdalene Visaggio (@Magdalene Visaggio)1611952243.0
What might be surprising is that Visaggio was able to generate the images without a background in graphic design, using freely available tools. She wrote on Twitter:
"A lot of people think I'm a digital artist or whatever, so let me clarify how I work. Everything you see here is done in Faceapp+Airbrush on my phone. On the outside, each takes between 15-30 mins. Washington was a pretty simple one-and-done replacement."
Ulysses S Grant https://t.co/L1IGXLI3Vl— Magdalene Visaggio (@Magdalene Visaggio)1611959480.0
"Other than that? I am not a visual artist in any sense, just a hobbyist using AI tools see what she can make. I'm actually a professional comics writer."
Did another pass at Lincoln. https://t.co/PdT4QVpMbn— Magdalene Visaggio (@Magdalene Visaggio)1611973947.0
Of course, Visaggio isn't the first person to create deepfakes (or "cheap fakes") of politicians.
In 2017, many people got their first glimpse of the technology through a video depicting former President Barack Obama warning: "We're entering an era in which our enemies can make it look like anyone is saying anything at any point in time." The video quickly reveals itself to be fake, with comedian Jordan Peele speaking for the computer-generated Obama.
While deepfakes haven't yet caused significant chaos in the U.S., incidents in other nations may offer clues of what's to come.
The future of deepfakes
In 2018, Gabon's president Ali Bongo had been out of the country for months receiving medical treatment. After Bongo hadn't been seen in public for months, rumors began swirling about his condition. Some suggested Bongo might even be dead. In response, Bongo's administration released a video that seemed to show the president addressing the nation.
But the video is strange, appearing choppy and blurry in parts. After political opponents declared the video to be a deepfake, Gabon's military attempted an unsuccessful coup. What's striking about the story is that, to this day, experts in the field of deepfakes can't conclusively verify whether the video was real.
The uncertainty and confusion generated by deepfakes poses a "global problem," according to a 2020 report from The Brookings Institution. In 2018, the U.S. Department of Defense released some of the first tools able to successfully detect deepfake videos. The problem, however, is that deepfake technology keeps improving, meaning forensic approaches may forever be one step behind the most sophisticated forms of deepfakes.
As the 2020 report noted, even if the private sector or governments create technology to identify deepfakes, they will:
"...operate more slowly than the generation of these fakes, allowing false representations to dominate the media landscape for days or even weeks. "A lie can go halfway around the world before the truth can get its shoes on," warns David Doermann, the director of the Artificial Intelligence Institute at the University of Buffalo. And if defensive methods yield results short of certainty, as many will, technology companies will be hesitant to label the likely misrepresentations as fakes."
Ancient corridors below the French capital have served as its ossuary, playground, brewery, and perhaps soon, air conditioning.
- People have been digging up limestone and gypsum from below Paris since Roman times.
- They left behind a vast network of corridors and galleries, since reused for many purposes — most famously, the Catacombs.
- Soon, the ancient labyrinth may find a new lease of life, providing a sustainable form of air conditioning.
Ancient mining areas below Paris for limestone (red) and gypsum (green).Credit: Émile Gérards (1859–1920) / Public domain
"If you're brave enough to try, you might be able to catch a train from UnLondon to Parisn't, or No York, or Helsunki, or Lost Angeles, or Sans Francisco, or Hong Gone, or Romeless."
China Miéville's fantasy novel Un Lun Dun is set in an eerie mirror version of London. In it, he hints that other cities have similar doubles. On the list that he offhandedly rattles off, Paris stands out. Because the City of Light really does have a twisted sister. Below Paris Overground is Paris Underground, the City of Darkness.
Most people will have heard of the Catacombs of Paris: subterranean charnel houses for the bones of around six million dead Parisians. They are one of the French capital's most famous tourist attractions – and undoubtedly its grisliest.
But they constitute only a small fragment of what the locals themselves call les carrières de Paris ("the mines of Paris"), a collection of tunnels and galleries up to 300 km (185 miles) long, most of which are off-limits to the public, yet eagerly explored by so-called cataphiles.
The Grand Réseau Sud ("Great Southern Network") takes up around 200 km beneath the 5th, 6th, 14th, and 15th arrondissements (administrative districts), all south of the river Seine. Smaller networks run beneath the 12th, 13th, and 16th arrondissements. How did they get there?
Paris stone and plaster of Paris
It all starts with geology. Sediments left behind by ancient seas created large deposits of limestone in the south of the city, mostly south of the Seine; and gypsum in the north, particularly in the hills of Montmartre and Ménilmontant. Highly sought after as building materials, both have been mined since Roman times.
The limestone is also known as Lutetian limestone (Lutetia is the Latin name for ancient Paris) or simply "Paris stone." It has been used for many famous Paris landmarks, including the Louvre and the grand buildings erected during Georges-Eugène Haussmann's large-scale remodelling of the city in the mid-19th century. The stone's warm, yellowish color provides visual unity and a bright elegance to the city.
The fine-powdered gypsum of northern Paris, used for making quick-setting plaster, was so famed for its quality that "plaster of Paris" is still used as a term of distinction. However, as gypsum is very soluble in water, the underground cavities left by its extraction were extremely vulnerable to collapse.
Like living on top of a rotting tooth: subsidence starts far below the surface, but it can destroy your house.Credit : Delavanne Avocats
In previous centuries, a road would occasionally open up to swallow a chariot, or even a whole house would disappear down a sinkhole. In 1778, a catastrophic subsidence in Ménilmontant killed seven. That's why the Montmartre gypsum quarries were dynamited rather than just left as they were. The remaining gypsum caves were to be filled up with concrete.
The official body governing Paris down below is the Inspection Générale des Carrières (IGC), founded in the late 1770s by King Louis XVI. The IGC was tasked with mapping and, where needed, propping up the current and ancient (and sometimes forgotten) mining corridors and galleries hiding beneath Paris.
A delightful hiding place
Also around that time, the dead of Paris were getting in the way of the living. At the end of the 18th century, their final destination consisted of about 200 small cemeteries, scattered throughout the city — all bursting at the seams, so to speak. There was no room to bury the newly dead, and the previously departed were fouling up both the water and air around their respective churchyards.
Something radical had to happen. And it did. From 1785 until 1814, the smaller cemeteries were emptied of their bones, which were transported with full funerary pomp to their final resting place in the ancient limestone quarries at Tombe-Issoire. Three large and modern cemeteries were opened to receive the remains of subsequent generations of Parisians: Montparnasse, Père-Lachaise, and Passy.
The six million dead Parisians in the Catacombs, from all corners of the capital and across many centuries, together form the world's largest necropolis — their now anonymized skulls and bones methodically stacked, occasionally into whimsical patterns. The Catacombs are fashioned into a memorial to the brevity of life. The message above the entrance reads: Arrête! C'est ici l'empire de la Mort. ("Halt! This is the empire of Death.")
That has not stopped the Catacombs, accessible via a side door to a classicist building on the Avenue du Colonel Henri Rol-Tanguy, making just about every Top 20 list of things to see in Paris.
An underground economy
However, while the Catacombs certainly are the most famous part of the centuries-old network beneath Paris, and in non-pandemic times draw thousands of tourists each day, they constitute just 1.7 km (1 mile) of the 300-km (185-mile) tunneling total.
Subterranean Paris wasn't just used for mining and storing dead people. In the 17th century, Carthusian monks converted the ancient quarries under their monastery into distilleries for the green or yellow liqueur that still carries their name, chartreuse.
Because the mines generally keep a constant cool temperature of around 15° C (60° F), they were also ideal for brewing beer, as happened on a large scale from the end of the 17th century until well into the 20th century. Several caves were dug especially for establishing breweries, and not just because of the ambient temperature: going underground allowed brewers to remain close to their customers without having to pay a premium for real estate up top.
Overview of the Paris Catacombs.Credit: Inspection Générale des Carrières, 1857 / Public domain.
At the end of the 19th century, the underground breweries of the 14th arrondissement alone produced more than a million hectoliters (22 million gallons) per year. One of the most famous of Paris' underground breweries, Dumesnil, stayed in operation until the late 1960s.
In that decade, the network of corridors and galleries south of the Seine, long since abandoned by miners, became the unofficial playground for the young people of Paris. They explored the fantastical world beneath their feet, in some cases via entry points located in their very schools. Fascinated, these cataphiles ("catacomb lovers") read up on old books, explored the subterranean labyrinth, and drew up schematics that were passed around among fellow initiates as reverently as treasure maps.
As Robert Macfarlane writes in Underland, Paris-beneath-their-feet became "a place where people might slip into different identities, assume new ways of being and relating, become fluid and wild in ways that are constrained on the surface."
Some larger caves turned into notorious party zones: a 7-meter-tall gallery below the Val-de-Grâce hospital is widely known as "Salle Z." Over the last few decades, various other locations in subterranean Paris have hosted jazz and rock concerts and rave parties — like no other city, Paris really has an "underground music scene."
Hokusai's Great Wave as the backdrop to the "beach" under Paris.Credit: Reddit
Cataphiles vs. cataphobes
With popularity came increased reports of nuisance and crime — the tunnels provided easy access to telephone cables, which were stolen for the resale value of their copper.
The general public's "discovery" of the underground network led the city of Paris to officially interdict all access by non-authorized persons. That decree dates back to 1955, but the "underground police" have an understanding with seasoned cataphiles. Their main targets are so-called tourists, who by their lack of knowledge expose themselves to risk of injuries or worse, and degrade their surroundings, often leaving loads of litter in their wake.
The understanding does not extend to the IGC. Unlike in the 19th century, when weak cavities were shored up by purpose-built pillars, the policy now is to inject concrete to fill up endangered spaces — thus progressively blocking off parts of the network. That procedure has also been used to separate the Catacombs to prevent "infiltration" of the site by cataphiles.
Many subterranean streets have their own names, signs and all. This is the Rue des Bourguignons (Street of the Burgundians) below the Champs des Capucins (Capuchin Field), neither of which exists on the surface.Credit: Jean-François Gornet via Wikimedia and licensed under
The cataphiles, however, are fighting back. In a game of cat and mouse with the authorities, they are reopening blocked passages and creating chatières ("cat flaps") through which they can squeeze into chambers no longer accessible via other underground corridors.
Catacomb climate control
Alone against the unstoppable tide of concrete, the amateurs of Underground Paris would be helpless. But the fight against climate change may turn the subterranean labyrinths from a liability into an asset — and the City of Paris into an ally.
The UN's 2015 Climate Plan — concluded in Paris, by the way — requires the world to reduce greenhouse gas emissions by 75 percent by 2050. And Paris itself wants to be Europe's greenest city by 2030. More sustainable climate control of our living spaces would be a great help toward both targets. A lot of energy is spent heating houses in winter and cooling them in summer.
This is where the constant temperature of the Parisian tunnels comes in. It's not just good for brewing beer; it's a source of geothermal energy, says Fieldwork, an architectural firm based in Paris. It can be used to temper temperatures, helping to cool houses in summer and warming them in winter.
One catch for the cataphiles: it also works when the underground cavities are filled up with concrete. So perhaps one day, Paris Underground, fully filled up with concrete, will completely fall off the map, reducing the city's formerly real doppelgänger into an air conditioning unit.
Cool in summer, warm in winter: Paris Underground could become Paris A/C.Credit: Fieldwork
Strange Maps #1083
Got a strange map? Let me know at email@example.com.
Meconium contains a wealth of information.
- A new study finds that the contents of an infants' first stool, known as meconium, can predict if they'll develop allergies with a high degree of accuracy.
- A metabolically diverse meconium, which indicates the initial food source for the gut microbiota, is associated with fewer allergies.
- The research hints at possible early interventions to prevent or treat allergies just after birth.
The prevalence of allergies arising in childhood has increased over the last 50 years, with 30 percent of the human population now having some kind of atopic disease such as eczema, food allergies, or asthma. The cause of this increase is still subject to debate, though it has been associated with a number of factors, including changes to the gut microbiomes of infants.
A new study by Canadian researchers published in Cell Reports Medicine may shed further light on how these allergies develop in children by examining the contents of their first diaper.
The things you do for science
The research team examined the first stool of 100 infants from the CHILD Cohort Study. The first stool of an infant is a thick, green, horrid-looking substance called meconium. It consists of various things that the infant ingests during the second half of gestation. Additionally, it provides not only a snapshot of what the infant was exposed to during that time, but it also reveals what the food sources will be for the initial gut bacteria that colonize the baby's digestive tract.
The content of the meconium was examined and found to contain such varied elements as amino acids, lipids, carbohydrates, and myriad other substances.
A graph of the comparative, summed abundance of different elements in a metabolic pathway after scaling to median abundance of each metabolite. The blue figures are those children without atopy, the yellow ones show the data for those with an atopic condition. Petersen et al.
The authors fed this information into an algorithm that used this data, along with the identities of the bacteria present as well as the baby's overall health, to predict which infants would go on to develop allergies within one year. The algorithm got it right 76 percent of the time.
A way to prevent childhood allergies?
Infants whose meconium had a less diverse metabolic niche the initial microbes to settle in the gut were at the highest risk of developing allergies a year later. Many of these elements were associated with the presence or absence of different bacterial groups in the digestive system of the child, which play an increasingly appreciated role in our overall health and development. The findings were summarized by senior co-author Dr. Brett Finlay:
"Our analysis revealed that newborns who developed allergic sensitization by one year of age had significantly less 'rich' meconium at birth, compared to those who didn't develop allergic sensitization."
The findings could be used to help understand how allergies form and even how to prevent them. Co-author Dr. Stuart Turvey commented on this possibility:
"We know that children with allergies are at the highest risk of also developing asthma. Now we have an opportunity to identify at-risk infants who could benefit from early interventions before they even begin to show signs and symptoms of allergies or asthma later in life."
A model for early childhood allergies
Petersen et al.
As shown above, the authors constructed a model of how they believe metabolites and bacterial diversity help prevent allergies. Increased diversity of metabolic products in the meconium encourage the development of "healthy" families of bacteria, like Peptostreptococcaceae, which in turn promote the development of a healthy and diverse gut microbiome. Ultimately, such diversity decreases the likelihood that a child will develop allergies.