Bots and Simulations > Evolution and Internet Sharing Sims
On Evolution and Population Decline
Numsgil:
Eric's 1000+ hour one? I think it shows exactly what I'm talking about. They learned the exact bare minimum to survive, and shortened their genome of anything that wasn't necessary for that goal. Evolution is really, really good at breaking things. If you want constructive behavior, you have to mix things up a bit.
shvarz:
--- Quote ---I've noticed that overall, average mutations increase as population increases. This makes sense. I've also noticed that with decreases, the relationship is the same, which also makes sense.
--- End quote ---
That, actually, does NOT make much sense. Not to me and not in this form, anyway. Population size does not directly relate to average number of mutations. Neither do the changes in population size.
Normally you should always see average number of mutations go up (in the long term), no matter what your population size is. This is simply due to genetic drift and silent mutations.
In some special cases population size may correlate with average mutations (but not determine it!). For example, if for some reason you suddenly have an excess energy in the sim and energy is easy to come by, then even unfit organisms will survive and the average number of mutation will go up. If you turn the energy spigot off, then all those unfit mutants will die off quickly and the average number of mutations will go down (non-mutated bots are more likely to survive). I see this kind of relationship a lot in my sims.
EricL:
--- Quote from: asterixx ---I've noticed that overall, average mutations increase as population increases. This makes sense. I've also noticed that with decreases, the relationship is the same, which also makes sense.
--- End quote ---
Normally, average mutations should always increase over the long run in mutating bots as Shvarz points out. BUT.... the Shinking Violet 2 I released in Internet Mode is marked mutations disabled. SV2 was also designed NOT to evolve. It is coded to commit suicide if it's DNA length changes. Thus, the "mutations" you see in the Average Mutatiosn graph in IM are in fact multiple viral infections of a few individuals - those individuals where the initial virus managed to disable the suicide DNA. This is likely the cause of the relationship you are seeing. I.e. higher populations mean higher virus production rate which means higher probability of an infection happening in the right way to kill off the suicide DNA which will translate into a larger number of alive, infected individuals in which infections can accumulate and spoof the Average Mutations graph into showing a higher average mutation value for larger populations. But in reality, only some SV2's have been infected and remained alive. The rest are mostly pristine uninfected, unmuated bots. Most successfully commit suicide when they get infected. Veggy population restrictions tend to prevent those infected bots without the suicide code from taking over. In short, don't expect the Average Mutations graph for SV2 in IM to be representitive for mutating bots in evo sims.
Also, I shoudl poitn out that even if you are running SV2 outside IM with mutations enabled, it still won't mutate like you'd expect, at least not at first. Not until mutations manage to kill off the suicide code and that lineage takes over, which is what happened to the original Shrinking Violet which was released into IM with mutations allowed.
--- Quote from: asterixx ---EricL, your 1000 zerbot write-up still astounds me, and was very helpful: Did you save a long-term graphs on that sim?
--- End quote ---
Thanks. Unfortunatly, I did not keep any long term graphs. I haven't run any evo sims in a while but it may be time again now that .sexrepro works and we have .totalbots, .totalmyspecies and virus immunity so that shepard/preditor bots can really come into play. I bet the Conditional Logic Prize could be claimed in fewer than 1000 hours through the use of well crafted preditor shepards...
Moonfisher:
I prefer oscilating mutations rates, with something like 100-200 cycles of strong mutation and 2000 with low mutations... that gives you a chance for more radical changes with good room for natural selection...
asterixx:
Thank you for your responses. Perhaps I should have been more clear. What I should have said was that the simulation that I was running with SV2 was the simulation in which I was noticing the pattern. I also should have saved the Avg. mutations graph ; they correlated strongly. The reason I simply stated the correlation, and not a general conclusion about causation (although it may have sounded like that) was because I really did not know what was in fact causing the pattern. Evidently it was how the bot was designed that I was uncertain about, so thank you for clearing that up.
--- Quote ---I prefer oscilating mutations rates
--- End quote ---
As for this, I'm going to try that right now and see how it works
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