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Week 10: Solving the Prisoner's Dilemma?

Anne Dalke's picture

Describe what happened when you played Prisoner’s Dilemma. Give an example of a prisoner's dilemma operating in your life. (An example: Peter and Anne have been trying to create a win-win situation in this class. Do you think that is possible? Can thinking out loud/reading/writing papers be a zero-sum game? If we all cooperate? When there's grading @ semester's end?)

Serendip Visitor's picture

After the game strategy

I did not think about a strategy necessarily before beginning the game. However, as the rounds kept going I found myself wanting to win. Originally I would cooperate because I received many coins but as the game took its toll I chose to compete. I found that strategy was alright and does help you in the end but for me it was more fun to risk it. I found that if we competed it was more entertaining and I ended up with more coins.

Serendip Visitor's picture

Two choices

I played multiple times and I found two strategies, and I think it depends on what you want to get out of this which is better to use. My first strategy, which is great if you don't care that you tie with Serendip or if it's better to tie with as much a possible. In this case, just cooperate in all 10 rounds, what I found is that the computer usually did whatever your previous move was, starting with cooperate in the first round every time, so if you cooperate every time you tie with 30 coins each.
My other option if you don't want to tie, but you want as many coins as possible I would cooperate for the first 9 rounds and compete in the last, in that case you would win with 32 coins and Serendip would lose with 27.

Serendip Visitor's picture

Don't See the Point

I chose compete for all selections and played the game several times. Despite being "scolded" about some "foul fate" at the end by the game's authors, my performance won 5 out of 5 times with an identical outcome each time. Serendip lost. I won.

Competition works. This website, if it was meant to demonstrate that collaboration works, fails. I'm sure collaboration can work at times, however, this website is not a luminous point in that explication. End of story.

Calála's picture

Playing against a computer...

 Sorry I forgot to post this before class...

But when I was playing the Prisoner's Dilemma game I found it hard to think seriously about strategy, knowing that I was playing against a computer. Seeing as the point of the game is to decide whether you should cooperate or compete with your opponent, I think who your opponent it is would affect the game. A computer has to either have completely random actions or have some preprogramed response. After playing the game, you realize that the computer copies whatever you do. So although your actions determine your opponents, the response can never change. It think it would me more interesting to play against another person, so that we could see whether personality changes the results of the game. An incredibly competitive person could choose to always compete. A computer cannot properly replicate a person's actions in this game.  

nbagaria's picture

   I played the game twice,


 I played the game twice, using different combinations of choices; however I always ended up with the same amount of coins (23). 

After playing the game I realized that since I was unable to judge exactly how my opponent would react,  I would try and balance out both my actions (compete and cooperate) and this happened both the times that I played. I did so possibly because I was actually concerned about what my opponent would “think” of me, even though I knew it really did not matter what it thought of me. The other possible explanation was that since I did not know my opponent's moves I did not want it to be able to make any sort of strategy or be able to predict my moves. Hence, I tried to make my moves as unpredictable as possible.


Serendip Visitor's picture

tit for tat

you see the opponent always uses the tit for tat strategy . assuming know this strategy ,[you can google it.]i would say that you should tit [or tat] him back .however when i did this ,he still said this or won, im thinking hes just a poor sport and is jeolous we won.also, you do know your opponents mooves based on the amount of money he got and the tit for tat strategy.and YOUR OPPONENT IS A COMPUTER! So dont worry. also, the opponent is smarter than you. (computer) no mater how much you try to be "unpedictable" he'll always do this .

please ecsuse my spelling .im only in 4th grade.
iris ;)

ED's picture

Cool- I get the idea

 I didn't quite get how the game really worked at first, because every time I played I won by five points. I think I cooperated three times, then competed a bunch of times, then cooperated then competed. I know the point of playing this game wasn't just "to win"; it was to make us think about the next (last) section of the course we're moving into, which is group work and negotiation in a large context that needs creating (BMC's curriculum/creating a college curriculum). Essentially, everyone has an idea of what they want a school to look like, but we don't have the resources to accomedate each and every one of our visions for the school... this should sound familiar (the Tragedy of the Commons). Our "Common" is the one single school we have to develop, and the tragedy is that we simply can't have everything we want. That's where negotiation comes in. In the Prisoner's dilemma, you had to realize that there is no winning... I mean, not really. What is winning anyway? I could get a higher score, which was satisfying, sure... what matters is that you couldn't "win" if you only "competed"-- and if you only cooperated, you'd be even (that isn't such a bad thing, is it...? Do hierarchies naturally exist?). This game is an interesting interactive metaphor for balance of considering cooperation/communal needs and individual drive, which we can apply to the curriculum conversations we'll be having and then also to the world at large.

ED's picture


 When i asked do hierarchies exist, I think I was thinking about the question of who should get to be allocated what in Tragedy of the Commons... see bottom of page 4, before "Pollution" talking about Yosemite.

Avocado's picture

So it took me a long time to find this... for some reason...

 I am a diehard fan of Law & Order (the original only, of course), and this game plays out basically every episode, to some respect.  Theirs is a one-shot, however, so it's different from playing the game, where you have to have one-ups on the computer with successive rounds.  The way to win against the computer is just to take advantage of the cooperation until the last minute, then compete when the computer has no hope of retaliation.  That seems to me to be the way to do it, anyway.... 

Every battle I have had with my darling brother has played out in this way.  For instance, if I throw away my mother's work by mistake (hypothetical, of course), and she is ready to murder whoever done it, there is a very real crisis at hand.  If my brother and I both remain silent, we will both endure her anger and move on.  If, however, I blame my brother for the whole thing I will be free from blame, and my brother will be grounded.  Hahahaaha-I think I would be advised to do this, since the one-time shot says I should maximize my own profit and completely disregard his.  This usually works extremely well for me, because even if my brother competes against me, tells on me and gets me grounded I will still be able to beat him up afterwards, which would successfully deteriorate both our profits...

maliha's picture

The Prisoner's Dilemma


  My first exposure to the Prisoner's Dilemma was in a computer science class in high school. We had to come up with a strategy for winning the game and then the teacher ran all the strategies against each other to see who ended up with the most points. My strategy was to start out cooperating, but then switch to competing, if the other person did, which actually failed miserably. I didn't understand how to win the Prisoner's Dilemma then, and I still don't. My first instinct is always to cooperate because it gives the greatest return to both players. If you compete, that might give you a larger gain, but only once, and then the other player will wise up and compete too, which is bad for both of you.

      I guess that's the part of the game that doesn't apply in real life; you don't get to redo things over and over again. You only have one chance, and if you compete while the other person cooperates, you win. That's why people are more drawn towards competing, when it would be better for the group, as a whole, if they cooperated. I mean, I can be competitive too, but I don’t really see life as a win-lose situation, where if one person wins, another has to lose.

ygao's picture

don't like this game

Ever since I could talk, I don't play games if I can help it. Games just don't attract me at all. It was no different when I played Prisoner's Dilemma. It seems pointless. I cooperated a few rounds and got the same points as Serendip. When I compete with it for once, I would get higher points. However, if I get back to cooperating, it would get the same points as I do again. It is just so random, that I don't really want to think about how it works! Or maybe it's just because I don't like figuring out how to play games in the first place. It seems unattactive to me, and I feel like games are just a waste of time.

A typical prisoner's dilemma in my life would be when I cooperate with a classmate on an exam or school work when we both are actually competing with each other in the class. It is just so frustrating knowing that your "study buddy" is in fact your competitor. When we are working together to help each other, it is just so ill-minded to think that there is a sort of "underground competition" going on behind the working together. I mean, where is the limit? Where do you draw the line to think that, hey, maybe I should stop working with her at some point when she isn't paying attention so that I can get a better grade? Where do you put your comforts and confidence in the other person knowing that s/he might be planning the same strategy as you? It really makes me sick to think about it every time I meet this problem. But then again, c'est la vie, this kind of problem exists in life all the time whether I like it or not, and there really isn't a way out. My best strategy is to just let it go, not think too hard so that I'll be in peace during most of the process, but will think eventually, when the time is right, to win in the end. After all, survival of the fittest requires competition, life is just a game, and whether I like games or not,  there's no where to hide.

c.k.koech's picture

two face

At first i didnt understand what the purpose of the prisoners dillemma was. then in class on tuesday lydia explained to me that it was like a scene in the movie The Dark Knight, the part where there are prisoners on one ferry, and civilians on the other, each have the remote to blow up the others ship so one of them can survive or at midnight they both get blown up, neither has communication with the other so they must make a decision to either sacrifice themselves or the other ferry.

putting it in this perspective made absolute sense to me, especially as the class continued into a conversation about alterior motives. Do we always make decisions that have area for some personal gain?

Prisoner's Dilemma was very cut and dry, I wanted to win so at first I cooperated and I kept on getting the same score as serindip but that didnt satisfy me so I began competing although it only allowed a one coin difference in our scores. at the end of The Dark Knight niether ferry blew up and Batman saves the  day. in real life batman wont be there, would we really sacrfice both of the ferrys because it is the right thing to do, or is it? would it be lose/lose bc they both die or win/win because they had good intentions?


ellenv's picture


I was not very serious while playing the game. At first, I attempted pressing only cooperate for an entire game, and then the next time I tried to do the opposite and simply push compete for the majority of the game. It seemed rather random to me and so the next time I tried to do a combination of compete and cooperate, with more compete than cooperate to be honest. I thought it seemed odd that I had read several things on the Prisoner's Dilemma before playing the game and yet I found that it was still hard for me to cooperate because all I was concentrating on was the number of points I had as compared to serendip. Had this been something that had more consequence in my day-to-day life, I think I would have taken it a lot more seriously and I probably would have tried to cooperate to a greater extent. 


In my life, an example of a zero-sum game/prisoner's dilemma comes with traffic and driving. When people on the road cooperate (for example, when there are two lanes going down to one) there can be a smooth and quick movement of traffic around the obstacle. On the other hand, if one person chooses to be aggressive and cut someone else off, then they may get around the obstacle a lot faster than the other person. What can happen though is that there can be two very aggressive drivers who decide to compete and the result is a crash and a bad day for both of the drivers. This type of situation appeared a great deal in my school parking lot after school because there was only one exit/entrance and no organization while at the same time there were a great deal of people eager to leave for the day. 

rmilitello's picture

Prisoner's Dilemma

 At first I was a bit confused by the game, I figured that if I continued to compete I would continue to get more coins than Serendip. I ended up with around 30 coins, and Serendip didn't have nearly as much. I had more coins in the end, so wasn't that the point? Well, apparently not. The catch was, if I cooperated with Serendip the game would continue for a longer period of time and both Serendip and I would get an equal amount of coins, but we would both have a lot more than if we would have competed against one another. Therefore, in the end it did seem like a win win situation. Why would I want to compete if I could get more coins by cooperating? 

I think that creating a win-win situation in class is possible. Of course there is grading at the end of the semester, and even if we didn't get the grades we would have liked wouldn't we at least have gotten something else out of the course? Maybe we learned to write a bit better, found our speaking voice, or just had fun. If we put something into the course and got something beneficial out of it, I think that qualifies as a win-win situation. 


When I think about a prisoner's dilemma  my relationship with my horse comes to mind. If we compete with one another (for example he stops listening to me because he doesn't want to exercise and I get annoyed and fight back by tugging on my reins and trying to force him to do what I want) it isn't going to work. If he wins I will most likely be on the ground and if I win he is going to give me a hard time every time I ride him because he remembers the last time I didn't consider what he wanted to do. However, if we cooperate and I let him do one of the activities he enjoys (like jumping) and balance that with some of the exercises he doesn't like to do, then that is when he will begin to cooperate with me. Any good relationship is about give and take, and although our first instinct is to try and get what we want, more often than not cooperating with one another makes for a much happier lifestyle. The truth is we can get what we want, but we can also give other people what they want as well. 

Serendip Visitor's picture

Prisoner's Dilemma?

While I played Prisoner’s Dilemma, my goal wasn’t to get as many coins as possible which may sound odd. My goal was to see how the system worked and why this was a dilemma. When I played it, I tended to cooperate all the way through until Serendip decided to stop letting me cooperate. When I tried to mix up my cooperation against competing, I never seemed to be satisfied with the results I got. When I cooperated and competed, the game immediately gave me a sense of angst and nerves. I didn’t like that I was competing for no reason except to win when I could easily keep cooperating to be satisfied with my coin amount. Personally, I was satisfied with my score when I was just cooperating and the angst I got from competing wasn’t worth the few extra coins that I was getting.

I think an example of a prisoner’s dilemma operating in my life would be any new friendship made during college. When you are making new friends, you don’t often “compete” with them because you want to win at something. I usually cooperate with people and get the feel of the person before “competing” against something. If you begin to “compete” too early in a friendship, the opposite person may be a weird/odd vibe and not know when to “compete” or cooperate.

And I think that creating a win-win situation in our class may be a bit difficult because we have so many different personalities with different opinions that it can be hard to come to a consensus about something. At the same time, I can picture the group to be able to compromise with each other over things, with Peter, of course, having to the mediator.

jrf's picture

only 30!

I, too, tended to come out with about 30 points no matter what I did, although I got more when I alternated cooperation with occasional cheating. I always ended up with almost exactly the same number of coins as Serendip, though, since each time I cooperated after having cheated, Serendip would take advantage of me. Even if it did help to be tricky at times, the best strategy I found also increased my partner's gains.

My relationship with my roommate is a non-zero sum game as well-- it is in both of our best interest to cooperate, even when that requires that we make compromises in our living space. If one of us enforced our will on every situation, she'd get what she wanted, but the other roommate would be miserable; if we decided to fight over everything, neither of us would win.

lkuswanto's picture

Prisoner's Dilemma and win-win solution

 I tried playing Prisoner’s Dilemma a couple of times and I always ended with around 30 points. I just randomly choose between compete and cooperate without knowing the strategy to win. I did not choose based on patterns or whatsoever. My pick was totally random. There was nothing that nudge me to choose a particular option over the other one.

Personally, I don’t think that Prisoner’s Dilemma can be used to best describe how we choose in our life. Prisoner’s Dilemma is limited to only 2 options, compete or cooperate. Besides that, there are more external and internal factors that do play part in nudging us to make a decision. In Prisoner’s Dilemma, our goal is just to get as many coins as possible, but there is not any particular circumstances that nudge us to choose either cooperate or compete. In real life, it is more complex than just randomly choose to compete or cooperate. Prisoner’s Dilemma may involve choosing an option and such, but in my opinion, it cannot be associated with choices in real life.

Win-win solution is an agreement between two parties where it is the option that may benefit both parties, or at least both gain the same amount of loss/benefit (fair trade). In a win-win solution, both parties have to sacrifice something in order to reach a mutual agreement.  One party has to give up something to gain something else from the other party and vice versa. In this case, our life always revolves around choice. Win-win solution seems to be the best answer for every choice that we want to make because we do not only gain benefit for ourselves, but also for people around us. Whenever I am faced with two difficult options and other people, I always try to find the win-win solution for me as well as the other people who are involved.

I agree with Maiya about our paper not being graded. It is actually a win-win solution where both the students and the professor may gain benefit. The students can improve their writing through the instructor’s feedback without having to worry about their grades while the professor can help the students with their writing without having to grade them (just commenting on them). Isn’t it the real purpose of having the seminar? To help the students develop critical thinking and get used to college writing? And I believe that developing critical thinking and getting used to college writing is all about how much effort you put in, not about grades.

avietgirl's picture

To compete or cooperate?

 I try playing the game but I was not able to get pass 36 like some of the classmates did. On my first try, what I have in mind was to win the game. In the process of playing, I figure that if I wanted to win the game, I would have to keep on competing. However, it would get bored and stop playing. I would still win, but I did not end up with a lot of coins. Then I figure that if I try to cooperate, the game would keep going and I would end up with more coins. However, I would be the same amount of coins as Serendip. I try competing and cooperating but I would still cannot get that many coins. It keep telling me that I can do better. I think that there is a way of doing both that get you the most coins. I think that the point of this game is to know when to compete and when to cooperate. A perfect combination of both is needed to end up with the most coins and win at the same time. 


pxie's picture

Back to rational or emotional again!

After reading the instructions of Prisoner’s dilemma, I tried to calculate the expected values of both choices, as I always do as a math person. The expected value for cooperating is -2 (the other one also cooperate, +3; the other one competes, -5). On the other hand, the expected value for competing is +6 (the other one cooperates, +5; the other one competes, +1). According to the rationally calculated result, the best strategy for this game is always competing. I did that, and I did earn more coins than Serendip did. But it popped out a hilarious but pretty true line, saying : BUT you were flirting with an Inconceivably Foul Fate the whole time! Sometimes, we win but we are not happy because we play foully, or at least ungracefully which makes our conscience suffer. In prisoner's dilemma, we try to get as many coins as possible at the cost some on else's loss. Especially, when I choose to compete and the other one chooses to cooperate, I get the coins but transfer the pain to the other one. When you thinking it on bigger scale, the possible coin to gain in total is always zero, as we know. Moreover, in this case, the possibility is not always equal. It is not always a 50-50 chance. Instead, people tend to trust and depend on each other when both of them are in trouble. Therefore, the chance that people will choose to cooperate is higher than to compete. It is the emotional way to think about this problem rather than simply counting the expected value in a mathematical way.

It somehow reminds me of playing pair sports. Usually, the pair is supposed to trust each other because they are partners. However, when one person doesn't trust another as much as the other one trusts her/ him, he/she alway wants to do all the work her/himself. The possible result is that he/she will win big acclaim. The other person losses the chance to show what he/she actually can do. The world is developing so fast that it seems impossible for any individual to complete a mission independently. We need to learn how to cooperate and live better off with other's help. (I don't mean taking advantage of others here). The prisoner's dilemma teaches us once again that sometimes, we have to make a decision emotionally and morally.

jtm715's picture

Winning the Game

For my first move, I considered whether the computer would act as (some) human(s), and try to be nice by cooperating on the first move.  I took a risk and guessed that it would cooperate so I could compete, and it worked out in my favor.  Going off of that initial win, I guessed that it would then try to make up for its losses, and compete, so I did the same and we both got a single coin.  I continued going through the game thinking about what the computer would guess next, but it seemed that the computer wasn't as conniving as I would be, and seemed to play like my sister would when we were little, and I, as the older one, could figure out her next move.  I'm having trouble thinking of something that applies to my own life, but the stock market completely encapsulates this idea.  People holding stock have to constantly guess if people are going to invest in their stock company, or if the company is going to suddenly come out with a great product.  They need to know when to buy stock and when to sell it to create the most profit out of their investment.  


Also- I just played the game again and employed the same strategy everytime and I always got the same outcome.  So the computer's choices aren't random, as far as I can tell. 

lcatlin's picture

frustration & friendship

What is completely frustrating for me about this game is that you don't know when it ends. At first, I thought it had a definitive amount of times it ended at every time but I just didn't know what it was so I competed the whole time so I could always be ahead of serendip. When Rachel said in class she got 69, I was shocked because I thought my score of 19 was high. I was just happy that I had won. After class I played with it more, and I decided that cooperation got you going the longest, and there was still a away to win if you always pressed competition. However, that doesn't get you the highest amount of points. I'm not sure there is a strategy, unless you decide what your objective is. If you want to last the longest, you cooperate the whole time. If you want to win, you compete the whole time and win.

I think this applies to friendship. If you cooperate with your friend the whole time and get along, your relationship will last longer.  If you compete all the time, you have a greater chance of winning if you are the one that initiates the competition, but you will lose friends quickly. The most frustrating this though, is you can have strategies to predict when it will end but in reality you can never pinpoint when it will exactly end. 

Lydia Jessup's picture

In the long run, cooperation pays off


When playing Prisoner’s Dilemma, I started out by competing and then switching to cooperating and then randomly competing for a few turns.  This strategy worked pretty well.  In the short run (for example, one turn) it may be beneficial to compete because you will get 5 coins until the opponent starts competing too and then you each get less than if you both cooperated.  So, in the long run it is beneficial to cooperate because you and your opponent will realize you will both get more coins per turn by cooperating. 

This reminds me of the Batman movie when the Joker traps innocent civilians on a ferry and inmates from a jail on another ferry.  If I remember correctly, each ferry is given a device that will blow the other one up.  They have a time limit and if one ferry blows the other up, they will be set free.  (I can’t remember if they will all survive if they both decide not to blow the other boat up or if he makes this ambiguous…) The civilians thought the criminals would press the button because they were heartless criminals, and the criminals thought the civilians would press the button because they knew the civilians thought they were bad, heartless people.  In the end no one pressed the button and they all survived because they had cooperated.  This is an unrealistic example, but is interesting to think about. 

The prisoner’s dilemma is so difficult because you can never know what the other person will do, but you have to make your decision based on what you think they will do.  In making your decision you should choose what would benefit you no matter what they choose.  In biology we discussed how and why humans and other animals (such as ants and monkeys) developed a dependency on groups.  This social behavior is contrary to the idea of “survival of the fittest.”  What some animals figured out is that although living in a group requires some compromises, in the long run everyone gains more from cooperating.     


hlehman's picture

My Dilemma with the Prisoner's Dilemma

 The first time I tried Prisoner's Dilemma I clicked compete every time.  I thought that the goal was to get the higher score so I was happy when I kept winning.  After that I tried different techniques each time, switching between compete and cooperate and I still kept winning so I got bored and quit.  

I think that the Prisoner's Dilemma is an interesting concept to apply to my own life.  I think that some of the hardest decisions we face involve the Prisoner's Dilemma.  I like to find a balance between cooperating and competing and often times such compromise does not exist and I'm torn.  When playing the game, I tried everything and since it always worked out I got bored- something I think can be a metaphor for bigger things in life.  When everything works out, people fall in the same habits, get bored, and either give up or just keep doing the same thing but no longer get enjoyment out of it.  That's why it is important to find a balance and understand that one cannot always win and it's not necessarily a bad thing.  

 I think that in order to create a "win-win situation" in our class, it is possible but will be difficult to achieve because you have to find that balance between competitors and cooperators that makes everyone happy and still completes the other goals of the class.

kdlz's picture

Yay cooperation! :)

   When i played prisoner's dilemma, at first I started out competing and found that while i competed, serendip cooperated, giving me 5 and serendip 0. however after that, serendip always competed, so (since i always competed as well) our totals only went up by 1 each turn. After a few rounds, i realized the the best way to play (i think!) was to cooperate from the start! i found that serendip generally only 'competed' after I competed first, thus if i cooperated, it cooperated too -- leading to the benefit of both of us. 

In my own life, i'm not sure where i might have a prisoner's dilemma. I guess one place i can see it in the classroom (echoing the people before me :D). I think that win-win situations occur when both the student and the professor are both putting in the necessary effort so that the professor does a good job in teaching his or her craft, and the student actually LEARNS something from the teacher. A win-lose situation would be if one end was putting in more effort than the other, such as if a professor puts in ALOT to try to make class fun/interesting, but the student doesn't put in the effort (doesn't care, sleeps, doesn't attend class etc) and thus doesn't learn anything. A lose-lose situation would be if neither cared? The professor doesn't put in very much effort to teach well and the student not putting in the effort to learn!

rshen's picture

66: My highest score

I was messing around with the game a bit trying to figure out how I could beat my previous scores. Solely cooperating put me at 35, solely competing at 16 and 47 when cooperating until 27 and then alternating. I failed to see a pattern in my more logical attempts and so i just starting messing around: my only reccuring trend was cooperating until 27.


And then I got 66. This score far surpassed my others and I was left riding my adrenaline rush wondering how this happened.


In some way, I feel this is a good metaphor for group work. When I begin a project, I kind of test the tide and lead at points and hang back and listen at others. But once I'm, say two days into a five day project, there are moments of personal inspiration that compel me to speak more. Or sometimes, I'm just completely indifferent to the conversation and tune out. But there's no predetermined pattern. Just like in Prisoner's Dilemma.

Shayna S's picture

Prisoner's Dilemma, a nudge in the wrong direction?

I found that the best strategy for Prisoner's Dilemma was to cooperate and compete at random intervals. Choosing either option too much or too little lowered my score, but if I went in a pattern, Serendip would recognize it.

In class, we talked about the example of class participation. Putting it into the context of the game, students compete for the attention of the professor. If students cooperate (for example, a group project), they gain somewhat equal amounts of attention. If they compete, (perhaps in an open discussion) each student recieves the same amount of attention, but less than when they cooperated. If a student decides to compete (say, by leading the discussion) and another student decides to cooperate (by continuing with the same discussion or by staying silent), the first student would gain more attention than the second. In the game, there is the critical number that, if a player falls below, will doom the player to an ill fate. This critical number represents the finite potential of the game (thus, it being a "zero-sum game"). There may be no end to students competing for a professor's attention, but attention is a finite resource. If a student loses that attention, it would be like falling below the critical number. He/she loses the game.

The idea of cooperation as an ideal has been brought up. In the game, cooperation was not well rewarded. There were no severe consequences for both players competing. A cooperative player, however, is more likely to experience the most severe negative consequences for their behavior on a case-by-case basis.  No coins, no attention, or all of the jail time.  It is quite apparent, then, that any winning strategy (winning as defined by having the best outcome quantitatively) cannot only include one option. Are you behind in coins, so you choose to compete? Or are you rolling in the cash, ready to cooperate? The question is: how are the sanctions of the game nudging us to compete or cooperate? Relating to Anne's questions: how are the sanctions of the looming end-of-the-semester grades nudging our class towards or away from a win-win situation?

thatcaliforniagirl13's picture

Competing doesn't necessarily have the best payoff

 At first I didn't really understand the purpose of Prisoner's dilemma. I wasn't quite sure of how I was gaining more coins and what was the difference between cooperating and competing. After playing a couple of times,I noticed that the more I competed, the more payoff I would get. I would end up with more coins than Serendip at the end. However, my gains were a payoff from being devious. I was told I had was "flirting with an Inconceivable Foul Fate." On the other hand, if I would randomly choose to cooperate then have random times to compete, I would end with the most coins, but with the result that I "could do better."

 After having played Prisoner's Dilemma, I found that in order to maximize your payoff or benefits and minimize punishments, there has to be some sort of agreement involved. I agree with Katie that it is definitely easier cooperate with one another. In that sense, cooperation is a win-win situation. It is definitely possible to have cooperation. However, at times more people are willing to cooperate more than others. It may be that they're more confident, prepared and potentially more trusting. Our class discussions are cooperative for the most part. However, I feel that at times I'm not cooperating as much as I should be for a number of reasons. In a way, I'm the person that is getting more from my classmates when I'm not saying much in return. As far as grades go, the ones that are willing to cooperate more in class and thinking aloud are the ones that are rewarded, not the ones that allow for deception. I have come to the conclusion that deviance isn't the right way to go. You may gain something temporarily. However, it isn't just your peers that lose in the end, the person not cooperating will lose as well. 

Annagibs's picture

It pays to be devious?

 When I started this game, I had a goal in mind: to see if I could trick Serendip into trusting me, and taking advantage of its "trust". Normally, I would feel bad having this sort of idea, but I figured it was a computer program so it really didn't have any feelings that would get hurt. My game method was to cooperate my first five turns, compete on the sixth, cooperate on the seventh, compete on the eighth, cooperate on the ninth, and then compete for the last two turns. I won with a 5 point lead, which was good, but it could have been better. My rational was to ease Serendip into believing that I would be mostly cooperative, and then "striking" with competition. 

What I kept thinking about while playing this game was the board game Risk.  I love playing Risk because it involves careful deliberation, similar to this game. When should I strike? When should I defend? Is a good defense a strong offense? What is the most opportune place to put my soldiers in order to start global domination (sounds diabolical, but it's actually very engaging)? Where is the best safe zone? Although you originally start off alone, you quickly form alliances with players you feel have similar interests to yours. And when they are the only competitors left, that's when you destroy them (I clearly like Risk too much). In this respect, there are win-win situations, until the end. When alliances are formed, both parties benefit from the combination of attack.

kgrassle's picture

Not Everyone is Able to Recognize the Value of Cooperation

 In the game, I was able to get the highest average amount of coins when I cooperated with Serendip.  When I tried to compete with it, it would compete with me, and we would both lose the potential to gain the most coins possible.  I believe that it makes sense for the computer to keep cooperating with me if I keep cooperating with it, but does this type of cooperation really happen in real life?  Looking at the overall picture, it makes sense to cooperate with people.  But what if people are used to always competing rather than working together?  For example, if an actual prisoner and his partner were held in different interrogation rooms and told that the first person who gives the other one up will get no jail time.  Then they were told if the other person chose first, they would get thrown into jail for many years.  If they both told on each other, however, they would only get a few years in jail.  It would make sense to cooperate so both of you get the same amount of time, but are these prisoners really going to care what happens to their accomplace?  Cooperation does not matter to criminals at all.

            Bryn Mawrters, however, are no criminals, and the group of women that I learn with are all very willing to cooperate.  We all realize that if we do our part of the work and attempt to contribute an equal share to discussions, we get the most out of our learning.  Everyone is willing to create a win-win situation.  This cooperation also plays a part in the grading scale.  We as students are able to play a large role in the grade we think we deserve.  If we know we have worked very hard and can convey that to the professors, I am sure we will be satisfied with our grades. 

            Equal cooperation will be especially important in the group papers that we will be writing.  If we don’t already see how equal cooperation can benefit both parties, we will experience this through writing with others.  When both people put in the same effort, a better relationship sprouts between the writers, making it easier to talk about ideas and write an actually interesting paper.  So even though people in our future work places may not see the value of cooperation, I have found that Bryn Mawr's community thrives with cooperation between one-another.    

Jessica's picture

When I kept on cooperating,

When I kept on cooperating, both Serendip and I won 30 gold coins. When I resorted to cheating occasionally, I ended up with more coins than Serendip but still less than what I gained when I cooperated. And when I kept cheating, I initially had more than Serendip, but ended up with the worst result because Serendip also decided to resort to cheating. Cooperating led to the best result!

I agree that a win-win situation in class is possible. If only professors put in time & effort, students aren't going to gain as much as they would've if they had put in some time & effort to learn, and vice versa. However, when both professors and students put in effort into making the class go well as possible, the class really is going to turn out productive (like our class! :] ) As for the thinking out loud, I honestly started out thinking it wasn't going to benefit me because my idea is out there for anyone to take, but it turned out that it helped me to defend counter arguments since people who disagreed with me pointed out what's wrong with my idea from their point of view. It also helped me to strengthen my argument when people who agreed with me commented on it, further expanding the argument. I don't necessarily think it works all the time with anyone, it takes a certain environment with cooperative learners (i.e. Bryn Mawr? haha).

I'm not sure what the question meant by grading @ semester's end, but I think grading is a bit harder to talk about because the amount of effort students put in might not necessarily match up with the level of performance in class. So it would really depend on what the professor defines win-win situation to be. A student can put a lot of effort and time but get an okay grade, not necessarily the best one. It would be nice if the grading's based on the effort though!

Another win-win situation in my life might be my extracurriculars. If I decide to make time to pursue my interests other than classes, then I would benefit tremendously by gaining distinct hobbies and becoming a unique, interesting individual. More importantly, my life would be much more enjoyable! At the same time, Bryn Mawr would benefit by having me in the school because I would increase the diversity and expand what I might be able to do as an undergrad and later as an alum (and possibly enhance the reputation). Hopefully I'm on my way there... haha :)

Maiya Zwerling's picture

Prisoner what?

 I honestly don't understand Prisoner's Dilemma. I tried a bunch of things that included only cheating, only cooperating and a mix of both. I was not able to get past thirty. Clearly, a mix of both is the best way for when to get the most out of it. I was not sure if we were supposed to win by the most or just get the most points in general so that made playing confusing for me. However, I would be interested to know the secret. 


Win win situations in life are clearly idea. They come as a result of luck situations that help both yourself and the people you are working with. I believe our class, because we don't have grades on our essays, is a win-win situation as long as the person writing the essay puts in the necessary energy to do well on the essay. If they are working hard to perfect their work even if it means not getting a reward (a good grade) from it, they are doing themselves a favor in the long run. I do not know if the grades at the end of the semester disrupt this because I do not know the significance of them. How are we graded? What are we graded on? If our effort it what we are graded on then it is still probably a win win situation because you are putting the efforts in to teach yourself and then you are getting the rewards from this. If they are based on performance, this is no longer a win win situation.


In my life, a win win situation is my relationship with my dog, Kelsey. She requires care including walking, feeding, attention and love. Giving her this makes me happy because she is a nice companion and I love having her around and feeling good. So even though I have to do work because she relies on me, her happiness makes a difference because it makes me happy. If I were taking care of something or someone that did not make me happy and in which I did not feel the rewards, I probably would not feel the same way.