A Wikipedia banner ad for a paid survey?

In the early hours of today, while researching Yippies on Wikipedia my report for the Communication Skills and Professional Issues modules, I stumbled upon a banner that was quite different from the usual "personal appeal"s.

Banner ad on Wikipedia for a Harvard public goods game

"Please help advance research", it said, "with a quick interactive online experiment". Sure, why not? I clicked the banner, and it took me to a website, which told me that I would be paid at least $10 for my participation. How nice of them. I continued to the survey, and was delighted to find that it was a public goods game. I had learned of these from the Behavioural and Experimental Economics module while writing notes for a student, and I was happy about the opportunity I had received to actually take part in such an experiment, and perhaps utilise some of what I learned in the module.

The first round had three or four members contributing some part of their $10 allowance. I decided that since I was given this money for no other reason, I might was well be trusting, and contribute. I think I contributed $9, as did another member. Someone else contributed a mere $3. I got $13 in total from that round. Another round had an ultimatum game. I split the cash 50-50, which turned out to be the minimum limit the other participant had set. Yet another round had a rather interesting game that I do not recall encountering before. It was one where I could transfer some amount from my $10 allowance to the other player. This amount is tripled when they receive it. So if I transfer all of my $10, they get $30. I transferred $7, and correctly anticipated a return of $10. So they got $11 and I got $13.

There were also a few other rounds about splitting money, and finally some questions about how much I trusted the participants and the surveyors. I expected a punishment game, but there were none, unfortunately. Anyway, I got $23, $2 of which I donated to the Red Cross, and $1 to the Wikimedia Foundation, keeping $20 for myself. It was really interesting to take part in the survey, and it's nice to have been paid for taking it. Thank you Harvard, Sciences Po and Wikimedia!