Bots and Simulations > Evolution and Internet Sharing Sims
A little evolution for everyone!
Carlo:
--- Quote ---You have to understand what it is you're testing. It's been a while, but I think you're testing if two supposedly events are NOT related. When you conclude that they are not NOT related, you can't conclude that they ARE related. Or something like that.
There are some subtle things you cannot conclude, but it's been too long and I just don't remember it all exactly. I think this is a case of that. I think sometimes F1 test give a false positive, but they won't give a false negative, or something like that.
--- End quote ---
A bit of confusion here, it seems.
We're trying to know the probabilities of two _completely related_ events: that is, A wins or B wins. The events are completely related because if A wins, B loses, and vice versa. Ok? We're just tossing a coin, and counting the times we have head, and the times we have cross.
But the sequence of results (A wins, B wins, B wins, A wins, B wins, etc..) is completely unrelated, since there's no information passing from one simulation to the other, so they cannot be related.
Hence, we can apply the same methods we use to calculate whether a coin is even or uneven (fair or unfair, don't know how you say). We toss it a zillion times, and calculate the ratio of head and cross, then we calculate the probabilities, and the error range inside a probability of, say, 90% (this means: that you have 90% chances that the real ratio is inside the error delta).
Numsgil:
--- Quote ---I also tested 4 different bots vs. their conspecies-cousins, and all the conspeices always did win 5-0 (and I concluded I didnt needed to making more or longer trails) and if the conspecies is so important, why doesnt it evolve in the first place?
--- End quote ---
You have to understand that evolution works from the individual's point of view, never from the species point of view. At least, that's the mainstream opinion in science at the moment.
So, while a species is more fit with a conspec gene, and thus able to win F1 battles, individuals that evolve to eat others of its own kind, especially when there aren't any other species around, have suddenly gained a huge advantage.
Imagine if I lock you in a room with another guy, and give you a bowl of jello every day to eat. You both will probably be alive, but you have to share your limited resources. If you kill and eat the other guy, you gain a huge advantage. You get all his meat, and you get the whole bowl of jello every day.
So why aren't we all going around killing and eating each other? Well, groups of genetically close humans tended in the past to battle, and manytimes eat (especially the heart, as part of ceremonies), other groups of non-genetically close humans.
Ants likewise often battle each other over territory, but only primitive ant species battle within the colony.
Basically, it is only advantageous to not kill close relatives because they are genetically similar to you, but to utterly decimate fourth and fifth cousins, because they aren't as likely to share your own genes.
So especially in an arena where it's only you and the plants, there's just no reason for a conspec gene. This isn't a limitation of the simulation, it's a fact of real life. Cooperative bacteria will evolve cheaters that steal food and eat other members if kept in isolation in a pitri dish.
Read the bot tavern's thread on Comesum, I think we discussed this a bit there.
Sprotiel:
I'll try to explain a bit more:
Each contest is a Bernoulli trial. If we knew the probability p that bot A wins the contest, then the probability that A wins n contests out of a sequence of N would be given by the Binomial distribution:
P(n) = C(N,n).p^n.(1-p)^{N-n}.
The maximum of this distribution is at n=pN and the variance is Np(1-p).
However, we only know the results and not the underlying probability, so we have to "invert" the binomial distribution and use Bayesian inference. Imagine bot A won more contests than bot B, to know if this is statiscally significant, we have to compare likelihood functions, e.g. the probability of obtaining n wins under the hypothesis p=0.5 and the probability of obtaining n wins under the hypothesis p=n/N. If we have reasons to think that the bots are equivalent, we should probably only revise this assessment if the ratio of the likelihoods exceeds 100. Thus, a 5-0 win could be considered barely significant (ratio: 32) while a 4-1 win isn't (ratio: 2.6).
Numsgil:
--- Quote ---I'll try to explain a bit more:
Each contest is a Bernoulli trial. If we knew the probability p that bot A wins the contest, then the probability that A wins n contests out of a sequence of N would be given by the Binomial distribution:
P(n) = C(N,n).p^n.(1-p)^{N-n}.
The maximum of this distribution is at n=pN and the variance is Np(1-p).
However, we only know the results and not the underlying probability, so we have to "invert" the binomial distribution and use Bayesian inference. Imagine bot A won more contests than bot B, to know if this is statiscally significant, we have to compare likelihood functions, e.g. the probability of obtaining n wins under the hypothesis p=0.5 and the probability of obtaining n wins under the hypothesis p=n/N. If we have reasons to think that the bots are equivalent, we should probably only revise this assessment if the ratio of the likelihoods exceeds 100. Thus, a 5-0 win could be considered barely significant (ratio: 32) while a 4-1 win isn't (ratio: 2.6).
--- End quote ---
That sounds familiar. I think that's what I was trying to say. It's been 2.5 years since I even touched stats.
Sprotiel:
--- Quote ---
--- Quote --- I also tested 4 different bots vs. their conspecies-cousins, and all the conspeices always did win 5-0 (and I concluded I didnt needed to making more or longer trails) and if the conspecies is so important, why doesnt it evolve in the first place?
--- End quote ---
You have to understand that evolution works from the individual's point of view, never from the species point of view. At least, that's the mainstream opinion in science at the moment.
So, while a species is more fit with a conspec gene, and thus able to win F1 battles, individuals that evolve to eat others of its own kind, especially when there aren't any other species around, have suddenly gained a huge advantage.
--- End quote ---
This isn't exactly true. Parthogenesis is a counter-example. Lizards have a tendency to become parthogenetic, however all species that become parthogenetic get extinct in a few tens of thousands of years. What happens is that this mutation is beneficial in the short term, but fatal in the long run since it decreases hugely the adaptability of the species.
OK, it's perhaps not relevant for DB since there's no mechanism to exchange genes between members of a species. Actually, I wonder if the concept of species itself is relevant for DB, for the same reasons.
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