Travel Reference
In-Depth Information
Something similar has been done using computerized life forms. In
2000, Hod Lipson and Jordan Pollack of Brandeis University carried out an
important study of such cyber-creatures.
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Lipson and Pollack created a diverse population of replicating life forms
in a computer, and competed them to see which could move most quickly
across a virtual fl at surface. These virtual life forms were simple. They were
controlled by a collection of virtual electronic circuits representing a mini-
malist “brain.” The brain circuits were connected to a variety of virtual body
parts such as rods and ball joints. The brains of these computer creatures
could move the rods and cause them to change their length, and could rotate
the ball joints that linked these rods together.
These “organisms” were allowed to replicate themselves in the com-
puter. The computer program that directed their replication was instructed
to introduce occasional random changes, so that mutant organisms arose
each generation. At random, the brain circuits could be switched to new pat-
terns, the linkages between the various rods and joints could change, and
body parts could change their character from one type to another. Because
the mutations happened at random, just as in the real world, most of the
mutant organisms were grotesque constructs that received random signals
from their “brains” and fl ailed about uselessly. A minority of them, however,
could do something useful.
The computer program then dumped each generation of organisms onto
a virtual fl at surface, and monitored how quickly they could crawl, hump,
writhe, or wriggle their way across it. The slowest creatures were condemned
to cyber-oblivion, and the fastest creatures were allowed to replicate and to
undergo further random mutations.
In experiment after experiment, selection for the fastest organisms
resulted in the emergence of certain types of body plans. One especially ef ec-
tive type was a little rigid pyramidal shape enclosing an angled rod that could
change its length. The little creature's brain was wired to drive the rod repeat-
edly down and backwards, sending it across the level surface like a pole-driven
punt on the River Cam. Another extremely ei cient creature was shaped like
an arrow. It “rowed” itself forward by two extensible arms set at angles to its
“head,” just like a little rowboat. A third creature, a twisted parallelopiped,
