From: Eugen Leitl (eugen@leitl.org)
Date: Sun Aug 25 2002 - 09:31:53 MDT
---------- Forwarded message ----------
Date: 25 Aug 2002 21:05:08 +1000
From: Alejandro Dubrovsky <s328940@student.uq.edu.au>
Reply-To: transhumantech@yahoogroups.com
To: Transhumantech <transhumantech@yahoogroups.com>
Subject: [>Htech] more evolutionary fun
(
http://www.newscientist.com/news/news.jsp?id=ns99992701
)
'Animals' grown from an artificial embryo
11:35 23 August 02 Exclusive from New Scientist Print Edition
Virtual creatures, with muscles, senses and primitive nervous systems,
have been "grown" from artificial embryos in a computer simulation. The
multi-celled organisms could be the first step towards using artificial
evolution to create intelligent life from scratch.
How cells with different senses combine to make an artificial organism
How cells with different senses combine to make an artificial organism
Each creature begins life as a single "embryo" cell, containing a string
of random numbers that represent its genome. Some genes tell the cell to
split in two, forming a joint between the two new cells. Others tell it
to develop different kinds of ability to make the organism move within
or sense its virtual environment.
Given a particular genome, each embryo cell will develop in a
predetermined way. For example, it could develop cells with the ability
to move the joints they are attached to, forming a virtual limb. Or they
could develop sensitivity to light or touch. Give the embryo a different
genome and it will develop into a different cell arrangement.
In a parallel with real cells, the virtual embryos contain simulated
chemicals that switch its genes on or off. When the simulation is run,
genes activated by the "chemicals" make the cell act in different ways.
And some of the virtual genes produce chemicals that activate other
genes.
Josh Bongard, an AI researcher at the University of Zurich, ran the
simulation until each cell had grown into a creature of up to 50 cells.
He then tested each one to see how well it pushed a simulated box. By
setting one creature against another, Bongard was soon able to find
which cells grew into the most effective "pushing" creatures.
Successful creatures
He then took the genomes that led to the most successful creatures and
mixed them to produce new genomes for his virtual embryos, which he grew
and tested. Bongard, who reported the work at the International Workshop
on Biologically Inspired Robotics at HP Labs, Bristol, now has a bunch
of creatures that excel at box-pushing.
"Evolution seems to figure out that it's useful to organise the growth
process," says Rolf Pfeifer who works with Bongard. "You get repeated
structures, and they discover things like increasing body mass helps to
push the block."
So far, none of the virtual creatures has grown the equivalent of a
brain - a dense collection of neurons in one region. Instead, they have
neurons connected through each cell, allowing the creatures to move and
sense in a primitive manner.
Bongard thinks brain-like regions will develop if the creatures are
given tougher tasks. "The mid-term goal is to keep posing increasingly
complex tasks to see at what point you get a centralisation of the
neural systems and where you start to see cognition," says Bongard.
This, he adds, would mark a move from evolving artificial life to
evolving artificial intelligence.
Once you have evolved a genome capable of producing such a complex
creature, it should be possible to build it, says Bongard.
Gerald Edelman a neurobiologist at the Neurosciences Institute in San
Diego, California, says the work is important because the muscles,
joints and nerves are evolved and grown together, which is necessary if
they are to work well as a unit.
Duncan Graham-Rowe
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