Tuesday, September 2, 2014

Modern population boom traced to pre-industrial roots

By the end of the Roman Empire, humanity had crossed a critical threshold of social organization that allowed more people to take advantage of economies of scale, says anthropologist Aaron Stutz. "The Consummation of  Empire," by Thomas Cole, portrays the wealth and culture of the period.

By Carol Clark

The foundation of the human population explosion, commonly attributed to a sudden surge in industrialization and public health during the 18th and 19th centuries, was actually laid as far back as 2,000 years ago, suggests an extended model of detailed demographic and archeological data.

The Public Library of Science One (PLOS ONE) recently published the analytical framework developed by Aaron Stutz, an associate professor of anthropology at Emory’s Oxford College.

“The industrial revolution and public health improvements were proximate reasons that more people lived longer,” Stutz says. “If you dig further in the past, however, the data suggest that a critical threshold of political and economic organization set the stage 1,500 to 2,000 years ago, around the start of the Common Era. The resulting political-economic balance was the tipping point for economies of scale: It created a range of opportunities enabling more people to get resources, form successful families, and generate enough capital to transfer to the next generation.”

Population dynamics have been a hot topic since 1798, when English scholar Thomas Robert Malthus published his controversial essay that population booms in times of plenty will inevitably be checked by famine and disease. “The power of population is indefinitely greater than the power in the earth to produce subsistence for man,” he wrote. The so-called Malthusian Catastrophe theory was penned just prior to the global census size reaching one billion.

Around 1800, the human population reached one billion. "The First Birthday Party," by Frederick Daniel Hardy, celebrates the strong intergenerational ties that helped make this milestone possible.

While it took hundreds of thousands of years for humans to reach that one billion milestone, it took only another 120 years for humanity to double to two billion. And during the past 50 years, the human population has surged to near eight billion.

“It’s mind-boggling,” Stutz says. “The human population has not behaved like any other animal population. We haven’t stayed in any kind of equilibrium with what we would consider a typical ecological niche.”

Economic historians and demographers have focused on societal changes that occurred during the Industrial Revolution as the explanation for this super-exponential population growth. An archeologist by training, Stutz wanted to explore further back in time.

“Archeologists are interested in looking at much earlier changes in human society,” Stutz says. “In addition to looking at data, we dig up things like people’s houses, community courtyards, agricultural fields, harbors and so on. That gives us this sort of holistic view of how human society and the environment influence one another over time.”

Even entertainment during the Roman Empire came at a human cost. "A huge swath of the population was feeding, quite literally, the dynamism that was taking place," Stutz says. "Thumbs Down," by Jean-Leon Gerome, dramatizes just how cruel and capricious life could be for the individual.

His analysis found that that the potential for the human population to burgeon despite environmental degradation, conflict and disease could be traced to a subtle interaction between competition and organization. At a certain tipping point, this interaction created opportunities for individuals to gain more control over their lives and prosper, opening the door to economies of scale.

Stutz cites the Roman Empire, which spanned 500 years, from just before the Common Era to 476 CE, as a classic example of passing through this threshold. One of the largest and most prosperous empires in history, it is noteworthy for economic and political organization, literature, and advances in architecture and engineering. And yet, on an individual level, life was not necessarily so grand. Farm laborers and miners were ground into short, miserable lives to produce all those surplus goods for trading and empire building. And large numbers of young males had to serve in the military to ward off rebellions.

“The vast majority of people who lived under Roman rule had a life expectancy into their late 20s or early 30s,” Stutz says. “A huge swath of the population was feeding, quite literally, the dynamism that was taking place in terms of economic and political development. Their labor increased the potential for providing more democracy and competition on the smaller scale. That, in turn, led to a more complex, inter-generational dynamic, making it possible to better care for offspring and even transfer resources to them.”

A modern-day garment factory in Southeast Asia echoes the Industrial Revolution. "We might wind up being back in a situation where a growing part of the population is basically providing labor to sustain a majority," Stutz says. (iStockphoto.com)

The tipping point had been reached, Stutz says, and the trend continued despite the collapse of the Roman Empire. “The increasingly complex and decentralized economic and political entities that were built up around the world from the beginning of the Common Era to 1500 CE created enough opportunities for individuals, states and massive powers like England, France and China to take advantage of the potential for economies of scale,” Stutz says.

 This revised framework for the underpinnings of human population dynamics could lead to better understanding of how economic and political organization is affecting modern-day society, he adds.

“We might wind up being back in a situation where a growing part of the population is basically providing labor to sustain a minority,” Stutz says. “You could certainly point to the sweat shops in the developing world. Another potential example is the growing income inequality that’s been well-documented in the United States over the last couple of decades.”

Related:
Dawn of agriculture took toll on health

Wednesday, August 20, 2014

The psychology of evil

Gaining a new perspective on the roots of evil and its effects on society.

By Maria Lameiras, Emory Magazine

Psychology 341 is a new Emory course focused on the study of “evil” behavior. It includes critical analyses of the distinctions between normal human behavior, moral depravity and psychopathology. In addition to individual acts of evil, the class studies incidents of genocide, terrorism and torture. At the end of each session, to balance the heavy topic, students share “antidotes to evil,” including uplifting stories and videos, and offer ways individuals can combat evil.

“I was on the receiving end of an evil act. The person who committed it had no concern for my feelings,” says Patricia Brennan, the professor of psychology who teaches the course. “This was not something I had experienced before, and it made me want to do research to get to the root of evil behavior. That was my inspiration for this course.”

On the first day of the class last Maymester, students developed their own group definition for the topic: “Evil is defined as 
a selfish human act that defies situational expectations, is intended to harm, and is accompanied by a lack of remorse for actions.”

The class “is very relevant because there is evil all around us, whether we choose to observe it or not,” says Amrita Chatterjee, a senior majoring in business. “How we defined evil, and how we can prevent it, molded my perception of evil and how we can take it on as a societal issue.”

Related:
Does lack of fear drive psychopaths?
Nazi medicine: A needle in history's side
Psychopathic boldness tied to U.S. presidential success

Tuesday, August 19, 2014

The physics of falling icebergs


Click here if video does not appear on screen.

By Carol Clark

For thousands of years, the massive glaciers of Earth’s polar regions have remained relatively stable, the ice locked into mountainous shapes that ebbed in warmer months but gained back their bulk in winter. In recent decades, however, warmer temperatures have started rapidly thawing these frozen giants. It’s becoming more common for sheets of ice, one kilometer tall, to shift, crack and tumble into the sea, splitting from their mother glaciers in an explosive process known as calving.

“Imagine a sheer, vertical ice face three times as tall as the tallest building in Atlanta breaking off from a glacier and flipping 90 degrees,” says Emory physicist Justin Burton. “In my lab, we can calculate how much energy is released during one of these events, which can be equivalent to several nuclear bombs.”

Burton studies the geophysics of calving icebergs in order to better understand and predict effects of climate change, such as sea-level rise.

“Ice coverage is one of the most sensitive indicators of climate change,” he says. About half of the loss of ice from the polar ice sheets is occurring due to melting and half due to iceberg calving. While it’s more straightforward to estimate iceberg melt rates, their calving rates are much harder to pin down.

Greenland's Ilulissat glacier is believed to have spawned the iceberg that brought down the Titanic.

For the 2012 film “Chasing Ice,” videographers endured subzero temperatures and years of patience to record stunning time-lapse footage of ancient glaciers receding. Their efforts also yielded the largest calving event ever captured on film. The area involved was about the size of Manhattan. The filmmakers described it as like watching skyscrapers rolling around in an earthquake and an entire city breaking apart before their eyes.

Direct field observations of calving icebergs are as dangerous as they are rare. So Burton and his colleagues developed ways to model these events in a controlled, laboratory setting. “We can measure things that can’t be measured in the field,” he explains, “and it’s also way cheaper and safer.”

He and his colleagues built a cylindrical, Plexiglas water tank as a scaled-down version of a fjord, similar to the ice-walled channel at the end of the Ilulissat glacier, which drains the Greenland ice sheet into the ocean. This well-studied glacier, also known as Jakobshavn, is considered an important bellwether for climate change.

While it is normal for glaciers to both accumulate and shed ice, Jakobshavn provides a vivid snapshot of how the shedding process has speeded up. The glacier retreated 8 miles during the 100-year period between 1902 and 2001, but has retreated more than 10 miles during the past decade. Greenland’s ice sheet appears to be out of balance, losing more ice than it gains.



Burton’s lab creates experimental models to gain a more precise understanding of these glacial processes. Rectangular plastic blocks that have the same density as icebergs are tipped in the water tank and the resulting hydrodynamics are recorded.

One hypothesis that the lab is investigating is how the waves unleashed by capsizing icebergs may be causing earthquakes that can be detected thousands of miles away. “It’s counterintuitive,” Burton says, “because usually you think of earthquakes as causing large waves and not the other way around.”

The lab models, however, suggest that the violent rotation of massive icebergs generates waves that release the brunt of their energy onto the sheer vertical face of the glacier, instead of dispersing most of it into the ocean.

“If we can correlate the frequencies of earthquake signals with the frequencies of icebergs rocking back and forth in the water, then that could be a direct measurement of the size of the icebergs that have broken off,” Burton explains. “Large iceberg calving events could then be detected and measured using remote seismic monitoring.”

Climate change and its impacts is one of the top problems in science, Burton says. “We’re seeing huge changes occurring within a few years and we’ve got to get on it. I’d like to think that, a few decades from now, we were able to do something.”

Photo of Ilulissat glacier by iStockphoto.com

Related:
Creating an atmosphere for change
Crystal-liquid interface visible for first time

Friday, August 15, 2014

The anatomy of fear and memory formation


Click here if video does not appear on screen.

“A huge number of genes and proteins are involved in new memory formation, and we’re trying to get at the basis of that,” says Emory psychiatrist Kerry Ressler. “One of the most powerful ways to study memory formation is through the process of fear-memory formation. And fear memories are also clinically very important because they underlie disorders like post-traumatic stress disorder, panic disorder and phobias.”

In the primitive brain region called the amygdala, fear looks much the same in a mouse as in a human, Kessler explains. “What the amygdala does, we know now through decades of work by many in the field, is it hard-wires neural connections to multiple subcortical and brain stem areas that lead to the hard-wired fear reflex of rapid breathing, sweating, increased heart rate and in some cases processes like a freezing response.”

Watch the above video to learn more.

Related:
Emory Medicine: The anatomy of fear 
Does lack of fear drive psychopaths?

Tuesday, August 12, 2014

Written in poo: The story of prehistoric life

The mighty T-rex may be long gone, but descendents of its lowly pooper-scooper, the dung beetle, are alive and well and still telling tales.

By Eddy Von Mueller, Emory Magazine

An iridescent beetle, bright as a bead, has caught a whiff of paradise. She makes a beeline for a pile of fresh manure, high as a hill to her, recently left behind by 
a Maiasaurus striding through the rookery on some motherly errand.

It’s a noisy place, this. The herd is a big one, and there are hundreds of nests here. Adult animals rumble, or possibly honk or hiss as they jostle each other. Some of the nests are already full of broken eggshells and little Maiasaurs bawling to be fed.

The beetle takes no more notice of the clamoring dinosaurs than they do of her. She has family matters of her own to attend to. She’s a dung beetle, and, the risk of getting stepped on notwithstanding, hanging around a bunch of nine-meter-long herbivores the size of SUVs means living very large. She burrows eagerly into the heap.

Later, burrows and their chiropteran hardihood will help her million-times-great-grandchildren survive the asteroid impact that will doom Maiasaura and most of her kind 
to extinction.

Later, her descendants will be digging 
into the dung of proto-elephants on the savannahs where an ape will stand, starting no end of trouble.

Later, pyramids will rise, and the civilization that erects them will fall, having ironically put the humble dung beetle, the scarab, at the very center of their cosmology.

For now, a “now” seventy-five million years ago, this beetle will lay her eggs inside the tunnel she’s made, and seal it snugly behind her when she leaves, ensuring that the larva will 
be secure in a chamber literally made of food. “It’s dinner and a nursery,” notes Anthony 
Martin, professor of practice in the Department of Environmental Studies in Emory 
College of Arts and Sciences and the author 
of a new book, Dinosaurs without Bones.

It is coprolites, or fossilized dinosaur dung, that allow us to reconstruct the heartwarming domestic scene described above. Martin's book collects and describes these and scores of other fascinating finds that he and his fellow trackers are using to glean surprisingly intimate insights into how dinosaurs and other prehistoric creatures moved, healed, hunted, ate and excreted.

Read the whole article in Emory Magazine.

Related:
Bringing to life Dinosaurs without Bones

Photo: iStockphoto.com