Why altruism wins
- Published on 15 May 2011
- Written by Nicholas C. DiDonato
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Evolution. Survival of the fittest. Red in tooth and claw. These familiar phrases all point to one aspect of evolution: its merciless ferocity. Yet, biologists have found altruism in several species of mammals, an unexpected surprise given the seemingly individualistic nature of evolution. Is altruism merely an anomaly, a fluke of nature, or does something deeper lie beneath? Evolutionary biologist Laurent Keller (University of Lausanne) and roboticists Markus Waibel and Dario Floreano (both from the Ecole Polytechnique Fédérale of Lausanne) have run computer simulations that may reveal the evolutionary benefit of altruism.
Keller, Waibel, and Floreano hoped to test an evolutionary theory that has fallen out of favor as of late, namely, that altruism enables genes to pass on without necessarily aiding the individual who has the genes. In other words, genes ride organisms who in turn propagate these genes. As long as the genes survive and live for another generation, the fate of the individual organism is irrelevant. The “survival of the fittest” means not the “survival of the fittest individuals” but the “survival of the fittest genes.” Thus, an organism sacrificing itself for the sake of its genes in the form of altruism makes sense in an evolutionary framework.
To perform their computer simulation, Keller, Waibel, and Floreano built robots that would evolve to search for small discs (the equivalent of food in the simulation). These robots moved on a set of wheels and had sensors, as well as a camera, to aid them in their hunt for discs. The computer program controlling each robot would undergo mutations, creating variation in the abilities of each individual robot to gather discs. The most efficient gathers would survive the next generation of mutations while the least efficient would die off. In essence, this process simulated evolution.
After hundreds of such simulations, the robots become quite adept at collecting discs. The researchers then decided to introduce altruism by tweaking the realm of possible mutations such that altruistic behaviors could emerge. Sure enough, once the possibility of altruism was introduced, altruism exploded onto the scene. The sharing of discs meant that closely related robots (in terms of genetic similarity) greatly increased the chances of their genes surviving.
For instance, if one robot had an above average number of discs and a kin robot a below average number, then, without altruism, only the first robot would pass on its genes. However, enter altruism, and the wealthy robot shares with the poor one, and thereby they both pass on their genes. Since they share a large portion of the same genes (being kin), those genes greatly benefit from altruism. The researchers found that the greater the kinship between robots, the more quickly they would share.
As stated above, this gene oriented theory of evolution has fallen out of favor. Evolutionary biologist and mathematician Martin Nowak (Harvard University) doubts the relevance of such computer simulations for evolution. He cautions that virtual simulations do not necessarily mimic actual biological processes, and therefore lend next to no support for a gene oriented theory of evolution.
Regardless of whether a gene based theory of evolution is correct or not, altruism remains a product of evolution. Some way or another, it won out over a purely selfish lifestyle. Perhaps evolution is not as brutal as typically imagined. Perhaps it is not so red in tooth and claw. Perhaps it is the very process that gave humanity altruism.
For more, see “Even Robots Can Be Heroes” in Science Magazine, as well as the original article “A Quantitative Test of Hamilton's Rule for the Evolution of Altruism” in PLoS Biology.