Even Robots Can Be Heroes

From Charles Darwin on, evolutionary biologists have struggled to explain self-sacrificing behavior. If evolution is all about the survival of the fittest, then why do animals from bees to people help others when it can hurt them or their chances to reproduce? Simulations of miniature robots that "evolve" helping behaviors have now provided a possible answer, confirming a 47-year-old theory that recently has come under attack: We help those who are most related to us because they are able to pass some of our genes to the next generation.

For all organisms, the ultimate goal is to pass on one's genes. The problem with altruism is that sacrificing individual gains for the greater good can compromise that goal. In the 1960s, biologist W. D. Hamilton pointed out that, actually, one could still pass on one's genes, or at least some of them, by helping a relative. According to his kin selection theory, the closer the relative, the greater this indirect benefit and, therefore, the more the helper should be willing to sacrifice in assisting that relative.

Studies of ants, wasps, bees, and termites, among others, have borne out this idea. But researchers could never quite verify the theory because they couldn't pin down exactly what the cost and benefits were or study them over the many generations needed to see evolution in action. And recently a few researchers have challenged the idea that relatedness is necessary for altruism's evolution, though they have their own critics.

Laurent Keller of the University of Lausanne in Switzerland wondered if he could resolve the debate using a computer simulation. He and roboticists Markus Waibel and Dario Floreano, both from the Ecole Polytechnique Fédérale of Lausanne, started with real-life robots that are just a couple of centimeters high. The robots have two independently operating wheels and a "nervous system" composed of sensors and a camera, which allow them to detect small discs—a stand in for food.


Robots learning to share. Dario Floreano explains how the evolving robots work.
Credit: EPFL News
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The researchers then created virtual representations of these robots on a computer so that they could observe the robots' evolution over time. In real life, random mutations build up over many generations, leading to adaptations that help organisms better survive in their environment. In the simulation, the researchers replicated this process by randomly varying the strengths of the various connections that made up the robots' nervous systems. Some of these "mutations" helped the robots better gather the food disks, while some made the robots less efficient at the task.

The simulations ran for hundreds of rounds, each time selecting the best food gatherers and culling the others. The process mimics natural selection, as only the most "fit" robots multiply (in clone form) in subsequent rounds. Every so often, the researchers checked their simulation results by programming a real robot with the same set of mutations. The virtual and real robots behaved similarly, says Floreano.

Once the team was comfortable with the virtual evolution environment it had set up, it added a new twist: It allowed the robots to share food disks with each other. If Hamilton's hypothesis was correct, "successful" virtual robots were likely to be those that were closely related and shared food with each other; that would help to ensure that at least one of them -- and some of the genes of both—would make it to the next round. (Two robots with a modest amount of food disks would both be more likely to be cut from the simulation, but if one robot gave all of its food to a second robot, that second robot would likely make the next round.) And indeed, altruism quickly evolved in the simulation, with greater food-sharing in groups where robots were more related, the researchers report online today in PLoS Biology. The more closely related the robots, the quicker they cooperated. "It shows how general the [theory] is, whether you are an insect, a human or a robot," says Floreano.

"This is a very original approach," says evolutionary biologist Jacobus Boomsma of the University of Copenhagen in Denmark. "The results are remarkably clear cut, given all the messy dynamics that might have appeared ... and show convincingly how tremendously robust Hamilton's rule is."

But Harvard University theortician Martin Nowak is more cautious about drawing conclusions based on computer simulations. Virtual robots are not a stand in for real life, he says. "[The work] tells us nothing about whether Hamilton's rule makes a correct prediction for actual biological systems," he says. Read More...

The Mathematics of Terrorism

Since the 1960s, the mountains of southern Colombia have been home to a war between the government and a leftist guerrilla movement known as the Revolutionary Armed Forces of Colombia, or FARC. The conflict has simmered for decades. Sometimes it flares up in battles with government forces, a terror bombing, or a particularly high-profile kidnapping. Sometimes it fades into the background as cease-fires or negotiations quiet the hostilities. FARC has been fighting for so long that the war has become almost like background noise, says Neil Johnson, a University of Miami physicist who travels to Colombia every year to visit his wife’s family. Even locals have become numb to the conflict. “There’s this war going on, but I didn’t think too much of it. You hear numbers of dead every day, like football results,” Johnson says. “It took me 10 years to realize that maybe there was important information hidden in those numbers.”
Johnson, who specializes in the study of complexity, is one of a new breed of physicists turning their analytical acumen away from subatomic particles and toward a bewildering array of more immediate human problems, from traffic management to urban planning. It turns out that subatomic particles and people are not that different, he explains. “The properties of individual electrons have been known for many years, but when they get together as a group they do bizarre things”—much like stock traders, who have more in common with quarks and gluons than you might think. So profound is the connection that quants (quantitative analysts, often with backgrounds in physics or engineering) have flocked to Wall Street, creating elaborate models based on the way markets have moved in the past. ArXiv, a clearinghouse for physics research papers, includes an entire section on “quantitative finance.”
Still, it was not until a chance 2001 meeting in Bogotá with Mike Spagat, an economist at Royal Holloway College, University of London, that Johnson considered modeling something as human as warfare. Spagat had a Colombian Ph.D. student named Jorge Restrepo who was gathering data on attacks and death tolls, provided by the nonprofit Center for Investigation and Popular Education, so he could look for patterns in the conflict. Johnson hoped the numbers could tell them something about how the individual particles—in this case, insurgents rather than electrons—functioned when put together in large groups.
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SOUFRIERE HILLS VOLCANO, MONTSERRAT

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This explosive volcano in the Caribbean has become one of the most closely monitored in the world. After a long period of dormancy, it erupted in 1995 and hasn't stopped since.

Its lava flows, explosions, and two-mile high ash clouds have left the majority of the island uninhabitable, and evacuations are frequent. Researchers at the Montserrat Volcano Observatory continuously monitor its activity. With permanent stations in and around the volcano, the group monitors seismic activity, ground swelling and sulphur dioxide and report their findings to the government of Montserrat. They also host other scientists from around the world who want to study this dynamic piece of earth. Read More...

BIGGER & BADDER THAN THE HUBBLE

It may look more like a perplexing work of avant-garde sculpture than it does a telescope, but make no mistake about it--the golden snowflake on a surfboard that is the James Webb Space Telescope will be the premier eye in the sky of the next decade. With the assistance of the Webb, astronomers hope to take a giant leap forward in understanding the origins of the cosmos.

It trumps all previous space telescopes by virtue of its 18 hexagonal reflectors, which combine to form a huge mirror roughly seven times larger than that of the Hubble Space Telescope. This will allow it to collect far more light to see with, enabling it to peer at the most distant objects in the universe. Since light travels in time as well as space, the further away the James Webb Space Telescope can see, the further back in time it can look, granting the world unparalleled glimpses of the light from the first galaxies.

This next-generation space observatory will yield vital clues about every stage in the history of the cosmos, from the formation of the universe to the evolution of our own solar system. Expected to launch in 2014, NASA has allowed us sneak peeks at how one goes about building a successor for Hubble. Read More...

PERITO MORENO GLACIER, PATAGONIA, ARGENTINA

Some places on Earth ooze with such rich scientific fodder they have become meccas for the research community. Here are a few hot spots that coax scientists out of their labs in droves.

As the planet continues to warm, most of the world's glaciers are retreating. But not the Perito Moreno glacier on Argentina's southernmost tip. Miraculously, this glacier has stayed about the same size while its neighboring glaciers in the Patagonian icefield have shrunk.

Scientists want to know why. Every year since 1990, researchers have trekked to this achingly beautiful place to measure ice loss, motion and thickness in these icefields, along with the depth of the glacial lakes below them. One hypothesis for Perito Moreno's stability: geometry. The physical characteristics of the land and lake bottom surrounding the glacier impede ice flow. Read More...