An example of cellular automata and Assignment 1b
A cellular automaton is a grid of interacting organisms which follow very simple rules of
interaction (e.g., behaviors). The goal in such cellular automata modeling is to come up with
pattern out of homogeneity. The formation of tribes subject to three loci: social act locus, mate
choice locus, and tag-based identification generate alternative tagged (e.g., red or blue) groups of
individuals that are altruistic within their own social group.
Haploid Sexual Model -- free recombination
1. Grid of cells wrapped over a torus
2. There are two “tags” in the system
3. Random mortality occurs and
vacant cells are colonised by the
progeny of the neighbour with the
highest social fitness
4. Social fitness is the net effect of
neighbours less the costs of
interacting with neighbours. Two
independent “acts” occur between
any pair of players
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In this example of a cellular automaton based on a simple social game, players at each cell have
an allele for the following three loci (free recombination will be explained in Chapter 4):
1. a tag (red or blue)
2. genes for mating rules (prefer self, non-self, random)
3. a gene for social acts.
The first two behaviors are quite simple. The tag is a simple label used to identify neighbors and
trigger what happens with the next two behaviors. The mating rule gene simply determines the
decisions to mate in the neighborhood. If the organism has a self-tag preference, it would strongly
prefer a neighbor with the same tag type as a mate. If it prefers a non-self tag, it would strongly
prefer to mate with a non-self tag type.
The social act locus will be something we explore in greater detail in upcoming chapters (chapter
6). If the neighbor has a altruistic behavior it would give fitness to others (e.g., at a cost to self)
that would be the recipient of the act. If it were “greedy” or a “thief” it would always try to take
fitness from neighbors to benefit itself. If it were mutualistic it would tend to interact with others
that generate a benefit. The rules of engagement are dictated by the software package and
determine how many individuals take part in these social acts.
Your assignment 1b: Research a generic cellular automata package available online that you
might use in developing your group projects. Also research a Game of Life CA available on the
Internet. Email links for i) your generic CA software package and ii) your specific Game of Life
CA to Sinervo (links to CAs are on a 1st come 1st serve basis. Some packages might include more
simple interactions than discussed in this pdf. EMAIL sinervo: [email protected].