Back
to indexJeffrey A. Fletcher, Mark A. Bedau and Martin Zwick
Summary
This paper describes the environmental affects on a population of agents that seek to continue their growth through consumption of resources and reproduction. The environment itself contained a quantified amount of information and utility, which was encoded using information-theoretic uncertainty and a restricted set of resources, respectively. Agents that adapted according to these environmental parameters were more successful than agents that ignored them. This was measured by an external and internal measure of adaptation. External adaptation was measured by the population size, which indicated how well a population was able to locate the resources in an environment. A more quantitative measurement was used where adaptive success is proportional to the increase in the normalized reference population size (a population which reproduces at random).The internal measure of adaptive success was determined through the utility of the environment, where the success is how much utility agents receive compared to non-adapting agents.
The experimental success of this approach indicates that increased information about an environment will help the overall agent population. Variations in the amount of information and utility of an environment correlate directly with the success of a population. Fletcher et al's work is not widely cited, but the underlying concepts seem intuitively sound.
Methods
Agents resided on a 128 x 128 grid, where each square contains a variable resource for consumption. Agents move by jumping up to 15 squares in any direction, knowing a certain amount about the resources at that location before they jump. The total resources for all environments are the same, they are simply redistributed over many trials. The internal and external measures of adaptive success are described in detail above.
Keywords
adaptive agents, internal measure of adaptive success, external measure of adaptive success, information, utility
Rating
5
Bibtex Entry
@inproceedings = { fletcher,
author = "Jeffrey A. Fletcher and Mark A. Bedau and Martin Zwick",
title = "Effect of Environmental Structure on Evolutionary Adaptation",
pages = "189--198",
url = "citeseer.nj.nec.com/140029.html"
}