I like it. One minor modification might make it even better: turn 96 can be the same as 97-100 rather than another D, since mutual D in 95 (after 94 mutual C) should be enough to establish clonehood. That way against clones it gets 99 mutual C and just 1 mutual D.
Also, if 1-94 aren’t all cooperation, it might be better to have it just defect the last 2 or 3 turns rather than the last 4.
Actually, in the initial environment, using 96,97 for the unprovoked D,C (instead of 95, 96) will be more successful. Like O, but unlike the first afterparty, this “late afterparty” (LA) will beat I in an environment of mostly I (score against I for last 6 turns: I gets 18, afterparty gets 16, O gets 21, and LA gets 20). It will also beat O in an environment of mostly it and O (against LA, LA scores 21 and O scores 14; against O, LA scores 14 and O scores 15. So if the environment has more than 1⁄8 LA, then LA is winning. From the above, if O and LA start out small and equal in an I-dominated environment, as I disappears LA will be around 40%, easily enough to come back and pass O). LA will lose to O in a strongly O-dominated environment , while the original version will win (Afterparty scores 17 against O, above O’s mirror-score of 15); but since that situation should never arise, I think that LA has the best chance of coming to dominate the environment. In fact, in an environment which started out I-favorable and with both O and both forms of afterparty, original afterparty’s only effect would be to hasten LA’s win by parasitizing O.
(Edited; I’d originally used the 3,5,0,1 payoff matrix instead of 4,7,0,1)
I still think it makes more sense to group 96 in with 97-100, though, as a turn where it only plays C if all matches so far have agreed. If 1-94 are all mutual C, then on 95 it plays D and opponent plays C, I’d think it should play D the rest of the way instead of going with C on 96 and then D on 97-100.
I ran some numbers and it looks like your way is better against late-defectors.
Here are 3 ways you could design Afterparty:
v1. D-C on 95-96, then D 97-100 against non-clones (your original proposal) v2. first D on 95, then D 96-100 against non-clones (my suggestion) v3. first D on 96, then D 97-100 against non-clones (a variation on my suggestion)
My intuition was that v3 would be better than v1, even if v2 was not, but it turns out that’s not the case. Version 1 scores the most against TFT (or variations of TFT that defect on up to the last 3 rounds). Compared to the others v1 has an extra CD and an extra DC (worth 7 points in total), v2 has two extra DD’s (worth 2 points in total), and v3 has an extra CC and an extra DD (worth 5 points in total).
Things only change if the opponent is designed to play D for the last several rounds. If the opponent is TFT with D on the last 4 rounds then v3 does best and v1 does worst, and if the opponent plays D on the last 5 rounds then v2 does best and v3 does worst.
I like it. One minor modification might make it even better: turn 96 can be the same as 97-100 rather than another D, since mutual D in 95 (after 94 mutual C) should be enough to establish clonehood. That way against clones it gets 99 mutual C and just 1 mutual D.
Also, if 1-94 aren’t all cooperation, it might be better to have it just defect the last 2 or 3 turns rather than the last 4.
I said 95,96 are D,C. I should have said “respectively” to make it clearer.
Actually, in the initial environment, using 96,97 for the unprovoked D,C (instead of 95, 96) will be more successful. Like O, but unlike the first afterparty, this “late afterparty” (LA) will beat I in an environment of mostly I (score against I for last 6 turns: I gets 18, afterparty gets 16, O gets 21, and LA gets 20). It will also beat O in an environment of mostly it and O (against LA, LA scores 21 and O scores 14; against O, LA scores 14 and O scores 15. So if the environment has more than 1⁄8 LA, then LA is winning. From the above, if O and LA start out small and equal in an I-dominated environment, as I disappears LA will be around 40%, easily enough to come back and pass O). LA will lose to O in a strongly O-dominated environment , while the original version will win (Afterparty scores 17 against O, above O’s mirror-score of 15); but since that situation should never arise, I think that LA has the best chance of coming to dominate the environment. In fact, in an environment which started out I-favorable and with both O and both forms of afterparty, original afterparty’s only effect would be to hasten LA’s win by parasitizing O.
(Edited; I’d originally used the 3,5,0,1 payoff matrix instead of 4,7,0,1)
Hmmm, for some reason I’d read that as D,D.
I still think it makes more sense to group 96 in with 97-100, though, as a turn where it only plays C if all matches so far have agreed. If 1-94 are all mutual C, then on 95 it plays D and opponent plays C, I’d think it should play D the rest of the way instead of going with C on 96 and then D on 97-100.
A C on 96 can benefit if the opponent is still TFT on 97.
Basically, going to defect too early can drive you to extinction when the rest of the population is still late-defectors.
I ran some numbers and it looks like your way is better against late-defectors.
Here are 3 ways you could design Afterparty:
v1. D-C on 95-96, then D 97-100 against non-clones (your original proposal)
v2. first D on 95, then D 96-100 against non-clones (my suggestion)
v3. first D on 96, then D 97-100 against non-clones (a variation on my suggestion)
My intuition was that v3 would be better than v1, even if v2 was not, but it turns out that’s not the case. Version 1 scores the most against TFT (or variations of TFT that defect on up to the last 3 rounds). Compared to the others v1 has an extra CD and an extra DC (worth 7 points in total), v2 has two extra DD’s (worth 2 points in total), and v3 has an extra CC and an extra DD (worth 5 points in total).
Things only change if the opponent is designed to play D for the last several rounds. If the opponent is TFT with D on the last 4 rounds then v3 does best and v1 does worst, and if the opponent plays D on the last 5 rounds then v2 does best and v3 does worst.
I already ran the numbers, and I think that Late Afterparty, version 4 with D-C on 96, 97, would have been most likely to have won this tournament.
Wikipedia.