Why instead, as I suggested, don't you try to run a looong simulation with mutrate of mutrates at 1 or so, so to evolve the best mutation rates?
This is an interesting experiment, but I have no idea what it is going to do. My head hirts when I try to think about all the stuff that is going to be involved in that. Thing with mutrate of mutrates is that mutrate has no advantage for current generation - it only affects the next generation and even then not directly. In general, organisms don't want to mutate - chances of getting better after mutations are minute. So the selection should drive to eliminate mutation rates completely. I guess.. I may be wrong...
Well, basically the mutation rates determine the probability of having an offspring more or less mutated. This simply means that they affect the probabilty of the offrspring being more or less successful. For each set of mutation rates, say that you have these three values:
a- probability for the offspring to be identical to the parent
b- probability for the offspring to be worse
c- probability to be better
Say that a realistic mutation rates set may have a=90%, b=9.98%, c=0.02%. The interest of the robot is to have a successful offrspring, so it has to maximize c while keeping a good ratio between a and b, which can be done by regulating the mutation rates set. So you can treat it like a mutation as every other: evolution will try to optimize mutation rates to give the better a, b, c ratios.
About the idea that evolution tries to eliminate mutation: it's wrong! As long as an organism has the ability to mutate, it can find some good mutation to be better than its competitors. Let's reason in terms of lions and gazelles. If evolutions succeeds in eliminating mutation in lions, gazelles, which still mutate, can always develop the ability to run faster. No lion will ever catch them again, since lions lost the ability to mutate. A gene which gives gazelles the ability to mutate is successful, because allowing the mutation of the genes for speed in the gazelle gene pool, has more probability to be passed to the faster gazelles, which survive better.
You can do this little experiment, anyway (I tried, and seemd to work - now that there are tools for leagues, should be even easier): just put in the same environment two copies of the same species, identical except for the fact that one has reasonable mutation rates, while the other one has mutations disabled. When I tried it, the species unable to mutate was usually (on average) wiped out by the other one in more or less time.
But would be really great to make the experiment seriously: that is, with tens or hundreds of tries to have precise numbers (and maybe with a good esteem of the average time for a species to take over the other one, and how this time is affected by mutation rates... ). Something may be done automatically with the tools for leagues. And maybe Shvarz knows wheter somebody would be interested in a paper on the subject :boing: