next up previous
Next: Evolving the Language Up: Artificial Life Previous: Natural Selection

Evolvability and the Language

A study was conducted comparing the patterns of evolution in four different (but very similar) machine languages [27]. It was found that two of the four showed a much greater magnitude of evolution than the others (measured as optimization through size decrease). Also, the two that showed relatively little evolution, showed a pattern of strict gradualism of evolution, whereas the other two showed abrupt jumps in evolution (punctuations). Of the two showing punctuations, one demonstrated gradual evolution between the punctuations, while the other showed strict stasis between the punctuations.

It is evident that many aspects of the evolutionary process depend on the structure of the underlying genetic language. Yet, there exists no body of theory relating the structure of the language to its pattern of evolution. This represents a hole in our evolutionary theory which was not evident before the advent of synthetic evolution.

This now presents a serious problem for the many engineers who work with evolution as a tool in design or optimization. In every case, the engineer creates a genetic system to describe the solution space, and then evolves that language. Some of these languages will be highly evolvable, while others will not. There is no theory to guide the design of these languages to enhance their evolvability.

Thomas S.Ray
Mon Jul 15 15:51:28 JST 1996