The Prisoner's Dilemma has been studied from so many perspectives that it seems almost superfluous to add yet another interpretation. This is yet another interpretation. Note that I said, almost. Not quite superfluous.
The math of this one is easy. If you have not yet worked it out for yourself, I will tell you that everyone who joins in the fun will end up with one of two different scores.
Those who opt for the letter C will all get the same score. Those who opt for letter D also will score the same as each other. The D-score will be higher than the C-score. This is a mathematical truism.
I have entered, and I can tell you now that I will opt for letter C.
If you want to score more than me, then of course, you should opt for letter D. And if you do that, I hereby offer you my congratulations. I know you will end up with a higher score than me. Well done.
I'm not completely clear on the rules of this game. But the writeup above seems to say that whatever score we end up with after all the cooperating and defecting has been analysed, will define the XP reward that we are given.
So if you want to win more XP than me, you should, as noted, select D. Conversely, if you want to win the same number of XP as me, then you should choose C. Note, however, that I am someone you have never met and never spoken with. As such, you care nothing for me. You have no interest in my choices or my scores in this arbitrary game.
Wait a moment you cotton-picking varmint. This case is not yet completely closed
Is your goal simply to achieve a higher score than the nameless, faceless individuals who opt for option C?
Or do you want to make the overall score, and hence, your own score, as high as you can?
If it is the former, then you can safely select option D, and move on, ignoring the rest of this exercise in Navel-gazing. Mathematics and logic together guarantee that no-one else will get a higher score than you. I repeat: Well done.
If you want to maximise your reward, however, then you need to understand another mathematical consequence of the rules of this quaint little game. For every person who selects C, the total number of points awarded increases. For every person who selects D, the total number of points awarded reduces.
Thus, as you might expect, the total rewards will depend on how many people participate, but the way this game has been constructed the average reward given to each participant will depend heavily on how many participants choose option C over option D. More C choices, means a higher overall reward.
Speaking personally, I have a low XP count. That comes from lurking rather than participating. The strength of having a negligible number of XP and no privileges associated with higher levels is that one realises that these things are unnecessary. XP really is a purely imaginary number. I can say with complete honesty that I have no interest in gaining or losing XP.
I know however, that some of you like to gain XP. Thus, I make my decision to participate and select option C with the sole objective of increasing the overall total score, and raising the score of all the other participants.
Since we are playing with the meaningless, utterly arbitrary commodity called XP, there is no loss — and hence no risk — to those of us who choose to select option C and thereby help to increase the rewards handed out to other players. Some of whom, no doubt, have some measure of concern about the XP value associated with their accounts here.
Psychology today
Given the analysis above, the game appears to be completely trivial. However, since E2 is populated by fairly intelligent people, including the originator of this game, it might be wise to seek some form of non-trivial aspect to the game.
Is it an experiment to see how many participants are selfish and how many are altruistic? Does the use of words like 'Cooperator' and 'Defector' betray a sense of moral values behind the experiment, and is the experimentor seeking to analyse the value systems of the participants?
While I have no idea about the game or its originator, I can offer some speculation.
I have watched the originator of this game with some interest over the years and he appears to be a bit of a geek. Not a malicious geek, but nevertheless, one who might be quite willing to perform pain-free experiments on his fellow noders.
Furthermore, while I do not claim to know any real history of the site, I sense that it has changed over the years into something softer and more community oriented than perhaps it was in the early days.
So my conclusion is that our dear Magister Ludi might be attempting to find out how many of his fellow noders put themselves before the community, and how many put community gain before personal reward. My suspicion is that the gamesmaster is expecting to see a high percentage of participants selecting option C.
Of course, I have no idea whatsoever about such motivations. And I might be lying through my teeth.
So, my fellow participants, make your choice: C or D.