Why I give my students a ‘tragedy of the commons’ extra credit challenge • Hacker News Board

Re: Why I give my students a ‘tragedy of the commons’ extra credit challenge

#21

Post by sosuke » Wed, Jul 22, 2015, 9:36 PM UTC

But the challenge doesn't make sense, there isn't much risk, no fear of being known. Economic studies have covered this before, would you rather make $50k where everyone else makes $75k? or make $40k where everyone else makes $30k and people pick the latter because they want to have more than their peers. Everyone getting the same points doesn't change anything relative to those around me.

In a paper score, assuming 100, 2 to 6 points just doesn't mean much. 6 points is greater than 5, it could take me from 84 to 90! I'll go for the gusto and try for 6. 2 points just doesn't make any difference, and I wouldn't feel any better getting 2 points.

Re: Why I give my students a ‘tragedy of the commons’ extra credit challenge

#22

Post by bradleyjg » Wed, Jul 22, 2015, 9:36 PM UTC

justonepost wrote: post #5

andresmanz wrote: post #3

> I’ve been giving it to students since 2008, and only one class has successfully mastered the challenge. That's a real surprise. The 2 points option is the safe one, so everyone should go with that. Sure, I could assume that all (or most) of the other students think so and just get the 6 points myself. But then again, chances are that the other students think the same. So let's just go with the safer 2 points.

No, the safe option is to get organized and plan out who is going to chose the 6 points. That way, you know if you secretly chose the 6 points when you were supposed to get 2, you will get nothing. Then it doesn't become tragedy of commons, but rather an experiment with vandalism. The experiment, IMO, isn't valid. In RL tragedy of commons, the selfish don't really suffer that much .. it's usually everyone else that d…

You want something that is perceived to be fair in order to minimize the chances of someone deciding he'd rather get nothing than 2 points.

If I were in the class I'd propose a weighted lottery where everyone had a chance to be one of the sixes but those with worse grades had a somewhat better chance. While there might be disgruntlement over the weight, I'd guess it'd be less severe than if someone that an entire fairness factor was being ignored.

An interesting questions would be what to do if someone issued an ultimatum to the group "give me one of the sixes or I will ruin it for everyone". I'd think in that case every move ends with no one getting any points.

Re: Why I give my students a ‘tragedy of the commons’ extra credit challenge

#23

Post by hcurtiss » Wed, Jul 22, 2015, 9:37 PM UTC

sosuke wrote: post #21

But the challenge doesn't make sense, there isn't much risk, no fear of being known. Economic studies have covered this before, would you rather make $50k where everyone else makes $75k? or make $40k where everyone else makes $30k and people pick the latter because they want to have more than their peers. Everyone getting the same points doesn't change anything relative to those around me. In a paper score, assuming…

Agreed, but your assumption may not be correct.

Re: Why I give my students a ‘tragedy of the commons’ extra credit challenge

#24

Post by nadams » Wed, Jul 22, 2015, 9:40 PM UTC

Smushman wrote: post #11

I see it as a simple equation. I don't think it says more than that about people. Can someone enlighten me as to why a 90% break point? Why not for example 50%? Is it because 90% introduces some level of collaboration or vice versa? Sans collaboration or any other useful information (people I may already know in the class, etc.), I would say at best you have a 50/50 chance of a total stranger choosing the option that…

I think we are missing some context - and that is very important to show if the students could communicate/collaborate (such as a homework question) or a test question.

> I would say at best you have a 50/50 chance of a total stranger choosing the option that is better for the common good.

It depends on factors such as the student's current grade. I would argue you are more likely to choose 6 if you have a lower grade.

> If it were the general public at large I would estimate at least 60% would choose the more personally beneficial option.

Here is an related experiment. Choose N random people, and offer 2 choices: $50 or $200 and run the same experiment.

Here is an interesting question - are people less "greedy" if the prizes/points have a greater span? Such as instead of 2 points and 6 what about 2 points and 20 points.

I think the experiment is interesting any way you think about it.

Re: Why I give my students a ‘tragedy of the commons’ extra credit challenge

#25

Post by sosuke » Wed, Jul 22, 2015, 9:40 PM UTC

hcurtiss wrote: post #23

sosuke wrote: post #21

But the challenge doesn't make sense, there isn't much risk, no fear of being known. Economic studies have covered this before, would you rather make $50k where everyone else makes $75k? or make $40k where everyone else makes $30k and people pick the latter because they want to have more than their peers. Everyone getting the same points doesn't change anything relative to those around me. In a paper score, assuming…

Agreed, but your assumption may not be correct.

You're right I vaguely remember seeing a very wide range of top scores possible. From 25 - 200

Re: Why I give my students a ‘tragedy of the commons’ extra credit challenge

#26

Post by xg15 » Wed, Jul 22, 2015, 9:41 PM UTC

I wonder if jealously could also play a role here. The option to choose 2 points doesn't seem completely risk-free to me from an "emotional" point of view:

Suppose you choose the 2 and the class was actually disciplined enough that the points weren't lost. Then you might think that there might very well be a small group of students who got 6 additional points because they were greedy and you were not.

If students underestimate the risk of all points getting lost, they might in turn overestimate the "risk" of getting less than others if they play it safe.

Re: Why I give my students a ‘tragedy of the commons’ extra credit challenge

#27

Post by jedmeyers » Wed, Jul 22, 2015, 9:44 PM UTC

Get together, auction the 6 point slots. Then, depending on whether it works or not, either evenly distribute proceeds to everyone or return the money to the auction winners.

Re: Why I give my students a ‘tragedy of the commons’ extra credit challenge

#28

Post by cortesoft » Wed, Jul 22, 2015, 9:44 PM UTC

TimPC wrote: post #9

I think this would be more interesting if there was a way to explicitly declare the marks post-curve. In the event the distribution of marks is smoothed to any sort of typically college distribution it's entirely rational to just select 6 points and not care whether 10% of the others do or not. Selecting 2 leaves you open to a worse result on a curve, but selecting 6 is nearly risk free if the distribution of marks i…

It says in the very first paragraph of the article: "All selections are anonymous, and the course grades are not curved."

Re: Why I give my students a ‘tragedy of the commons’ extra credit challenge

#29

Post by overpaidgoogler » Wed, Jul 22, 2015, 9:44 PM UTC

Really odd that the professor does not mention carbon taxes in the story. It doesn't make sense to borrow game theory from economics but completely ignore the idea of taxing externalities

Re: Why I give my students a ‘tragedy of the commons’ extra credit challenge

#30

Post by MatthewWilkes » Wed, Jul 22, 2015, 9:47 PM UTC

Perhaps it's just cultural differences, but nobody getting extra points sounds like the most desirable outcome to me. Perhaps in a setting where the exam doesn't count for anything it'd be okay, but it just seems so juvenile.