Artificial Life Essay, Research Paper

rtificial life (commonly called a-life) is the term applied

collectively to attempts being made to develop mathematical models and

computer simulations of the ways in which living organisms develop, grow,

and evolve. Researchers in this burgeoning field hope to gain deeper

insights into the nature of organic life as well as into the further

possibilities of COMPUTER science and robotics (see ROBOT). A-life

techniques are also being used to explore the origins and chemical

processes of metabolism. Some investigators have even proposed that some

digital “life” in computers might already be considered a real life form.

Background

The term artificial life was coined in the 1980s by Christopher Langdon,

a computer scientist at Los Alamos National Laboratory and the Santa Fe

Institute. Langdon organized the first experimental workshop on the subject

at Santa Fe in 1987. Since then other a-life conferences have taken place,

drawing increasingly wider attention and a growing number of participants.

Theoretical studies of a-life, however, had been in progress long before

the 1980s. Most notably, the Hungarian-born U.S. mathematician John VON

NEUMANN, one of the pioneers of computer science, had begun to explore the

nature of very basic a-life formats called cellular automata (see AUTOMATA,

THEORY OF) in the 1950s. Cellular automata are imaginary mathematical

“cells” –analogous to checkerboard squares–that can be made to simulate

physical processes by subjecting them to certain simple rules called

algorithms (see ALGORITHM). Before his death, von Neumann had developed a

set of algorithms by which a cellular automaton–a box shape with a very

long tail–could “reproduce” itself.

Another important predecessor of a-life research was Dutch biologist

Aristid Lindenmeyer. Interested in the mathematics of plant growth,

Lindenmeyer found in the 1960s that through the use of a few basic

algorithms–now called Lindenmeyer systems, or L-systems–he could model

biochemical processes as well as tracing the development of complex

biological forms such as flowers. Computer-graphics programs now make use

of L-systems to yield realistic three-dimensional images of plants.

The significance of Lindenmeyer’s contribution is evident in the fact

that so-called “genetic algorithms” are now basic to research into a-life

as well as many other areas of interest. Genetic algorithms, first

described by computer scientist John Holland of the University of Michigan

in the 1970s, are comparable to L-systems. A computer worker trying to

answer some question about a-life sets up a system–an algorithm–by which

the computer itself rapidly grades the multiple possible answers that it

has produced to the question. The most successful of the solutions are then

used to develop new software that yields further solutions, and the cycle

is repeated through several “generations” of answers.

Evolutionary Modeling

Langdon himself picked up on the work of von Neumann by attempting to

design an “a-life” form on a computer screen. In 1979 he finally succeeded

in developing loop-shaped objects that actually reproduced themselves, over

and over again. As new generations spread outward from the initial

“organisms” they left “dead” generations inside the expanding parameter.

Langdon noted that the “behavior” of these a-life forms genuinely mimicked

real-life processes of mutation and evolution. He eventually proposed that

a-life studies could provide keys to understanding the logical form of any

living systems, known or unknown.

One of the most striking a-life simulations of evolutionary processes

has been the work of Thomas Ray of the University of Delaware, who in 1990

set in motion a “world” of computer programs that he called Tierra. The

world started out with a single ancestor, a program containing 80

instructions. A-life evolution proceeded as mutations rapidly appeared. The

new forms included “parasites” that interacted with the original host

forms, producing further mutations of hosts and parasites that “learned” to

deal with one another anew in each succeeding generation.

Braitenberg, Valentino, Vehicles: Experiments in Synthetic Psychology

(1984); Langdon, Christopher, ed., Artificial Life (1988); Levy, Steven,

Artificial Life (1992); Pagels, H. R., The Dreams of Reason (1988); Prata,

Stephen, Artificial Life (1993).