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5 December 2013 11:26 am ,
Vol. 342 ,
Dyslexia, a learning disability that hinders reading, hasn't been associated with deficits in vision, hearing, or...
Exotic, elusive, and dangerous, snakes have fascinated humankind for millennia. They can be hard to find, yet their...
Researchers have sequenced and analyzed the first two snake genomes, which represent two evolutionary extremes. The...
Snake venoms are remarkably complex mixtures that can stun or kill prey within minutes. But more and more researchers...
At age 30, Dutch biologist Freek Vonk has built up a respectable career as a snake scientist. But in his home country,...
Since arriving on the island of Guam in the 1940s, the brown tree snake ( Boiga irregularis ) has extirpated native...
An animal rights group known as the Nonhuman Rights Project filed lawsuits in three New York courts this week in an...
Researchers have been hot on the trail of the elusive Denisovans, a type of ancient human known only by their DNA and...
- 5 December 2013 11:26 am , Vol. 342 , #6163
- About Us
Evolving Toy Story
30 August 1999 8:00 pm
Few people over the age of six would think of Lego construction toys as the building blocks of life. But now two scientists have shown that it is possible to "breed" a working Lego structure, such as a bridge or a crane, without any human intervention. The researchers call the result, published in the current Artificial Life, a step toward the "evolutionary" design of robots.
Brandeis University computer scientist Jordan Pollack and graduate student Pablo Funes brought to life their bridges and cranes on a computer, using a type of program known as a genetic algorithm. Inspired by the biological process of evolution, the program starts with 1000 randomly chosen brick designs and lets them evolve in two different ways. "Mutation" means that a brick's position in any particular design is randomly modified, or a brick is added at random. "Crossover" means that components of two "parent" designs are randomly switched--a process akin to sexual reproduction. Each of the resulting "offspring" is rated according to its fitness for the desired task: for example, how heavy a weight the structure could lift without falling over. After breeding many "generations" (which usually took a day or two), a structure would evolve that seemed ready for its task. At that point, Pollack and Funes built and tested it.
The cranes that emerged from the genetic algorithm look like nothing a human would build; clumsy and ungainly, they have all sorts of unnecessary bumps and lurch forward as they strain to pick up a one-pound weight. But that's not the point, says Pollack. What matters, he says, is that "an incredibly stupid and simple algorithm" regularly evolved features that had not been programmed into either the algorithm or the fitness rating. The cranes, for example, always evolved vertical struts that added strength to the diagonal arm. What's interesting, says Pollack, is that the program "rediscovered basic engineering constructions."
"The unique thing about [Pollack's] work is his use of modular, buildable components and his actual building and testing of the evolved structures," says Randall Beer, a robotics researcher at Case Western Reserve University in Cleveland, Ohio. However, Beer adds, evolving robots that move, rather than cranes or bridges that simply bear weight, will be a much more challenging problem, in part because the physics of moving parts is more complicated.