Assignment 3

Due to a TA by 1:30pm, July 30. You may work in a group of up to three students, but each individual must be involved in every question. Do not assign problems to individuals within a team! Please submit only one solution per group.

Your solutions must be typed.

For this assignment you will read a research paper entitled ``Evolution of Communication with a Spatialized Genetic Algorithm,'' describing an artificial life experiment run to demonstrate evolutionary mechanisms that can account for communication between animals. This paper is available on the Web at

www.sunysb.edu/philosophy/faculty/pgrim/evolution2.htm
I handed out a paper copy for those who prefer reading from paper. (You may want to refer to the Web copy for the better diagrams, however.)

For this assignment you will read Sections 1 through 4 of the paper and answer a series of questions requiring some analysis of the paper. (I also recommend Sections 5 and 6 of the paper as being quite interesting - I just don't want to require that much reading.)

All of the following questions require relatively short answers (at most seven sentences). But they do require a fairly deep understanding of the selected paper.

Question 1

The reading describes two general experiments, one in Section 3 and one in Section 4. (Section 3 actually describes three experiments. The first results are graphed Figure 2. The other two were designed to fix a perceived design flaw uncovered in the first; their results are graphed in Figures 3a and 3b.)

In your own words, describe the fundamental differences in animal behavior that distinguish the experiments of Section 3 from the experiment of Section 4. That is, how is the lifetime of an individual animal different? (The reduced number of initial strategies is not a feature of animal behavior.)

Question 2

The experiment of Section 4 is also different from those of Section 3 in that the initial world of the Section 4 experiment begins with a small random collection of ``Adam and Eve'' strategies. What, in your own words, is the experimenters' purpose for beginning the world in this way?

Question 3

In presenting the results of Section 4, the paper shows diagrams of the world after a number of generations (Figure 5, page 10). The paper does not give similar diagrams for the first experiment of Section 3, whose results are graphed in Figure 2 (page 6).

As accurately as possible, describe what the world would look like after 600 generations. Figure 2 indicates that the world contains about 70% of animal <1,0,1,1> and 30% of animal <2,0,1,1>, but how would these be distributed in a picture? Justify your answer.