Scientific Method / Science & Exploration  Group dynamics key to
avoiding tragedy of the commons  In a paper published this week
in the Proceedings of the National Academy of …  In a (now
famous) 1967 article in Science, ecologist Garrett Hardin
discussed a situation he called the "tragedy of the commons." To
illustrate, he described a group of cattle ranchers grazing
their herds on public land. For each rancher, the decision to
add another cow is easy: for every cow they can add, they
(obviously) gain the entire value of that animal come market
time. Is there a cost? Yes, each additional cow depletes the
shared resource of the pasture a bit more, but the cost is
spread over all the ranchers, which makes the incremental change
that much more difficult to detect.  This arrangement may work
for quite a while—as long as the number of cattle is much
smaller than the land can support—but as the limit is reached,
the effects become clear and the bill comes due. Despite
increasingly problematic degradation, the equa