Minecraft is a blank canvas—the world exists, and you can build whatever you want out of it. That tabula rasa quality is only multiplied when multiplayer gets involved—get a bunch of people together, put them in a map, and almost anything can happen.
If you're really devious, you can put people together into an unwitting experiment and document the results. And what do you know, that's just what Minecrafter WordWorksExperiment did, as reported in a lengthy post on the Minecraft forums.
In the experiment, the tester put 30 players into a stripped, depressing plot of land with limited resources, told them they couldn't leave the established boundaries, and watched what happened. This is far from a confirmed study—it's really just one forum poster's story, and without any actual documentation, it's entirely possible that the entire thing has been fabricated. If it IS all made-up, it is at the very least an entertaining bit of Minecraft storytelling.
Soon after the study began came the strip-mining, then came the scarcity. (Clay vanished within three days.) After that, came the alliances—teams broke into four guilds, communicating mostly using out-of-game methods. "The Brotherhood," "The Axe," "The Dwarves," and the "Merchant's Guild." They soon turned their attention to diamond-mining (no seriously), and before long conflict began to foment.
Two players known as "the dick-ass griefers" began to build a base that was renewable and easily defensible, and eventually sand ran out, glass became a rarity, raids broke up a lot of the resources, and things got dark, indeed. But of course, it could always get darker:
Five weeks into the experiment a lot of players had lost the will to play. Most players resorted to staying underground and endless 2x1 tunnels were formed, giant chasms were found by players overmining and ultimately a large majority of cobblestone was lost through lava and the players fighting each other. Due to massive mining to and strip mines the corner of the map supporting the dick-ass griefers base sunk farther and farther down to the bedrock, leaving a noticeable drop in elevation between the two corners of the map. Buildings made out of dirt started showing up on the torn earth because most players lacked the resources to make pickaxes and couldn't meet the prices of the Merchant's Guild. These buildings were built with the only purpose of protection from monsters at night since the map became un-survivable during the night. At this point the large loss of land in the bottom half the map did one purpose. Eliminate the dwarves who were housed there. (I still can't believe the amount of stone removed and lost in that area, It's a devastating amount and continued until the 2 months were up). At this point a cycle was emerged, the players were fighting for the last bit of grass on the map (disregarding the griefers base that was inaccessible). But most of them were either trying to mine cobblestone for more trade with the Merchant's Guild for sticks for more pickaxes or trying to survive the night in dirt houses. It was a vicious cycle that was barely profitable. But a pattern did emerge. The players were effectively working together to survive the night. While there was still rampant war and grief the players that had little had banded together to try to survive the harsh environment.
At the end of the experiment, the tester asks: If the players who were trapped in this harsh world were suddenly given access to a wide-open, fresh Minecraft world, how would they react? Would they work together to build a sustainable community? Or would they faction up and strip-mine it all over again? Given what we've seen on our own (real) planet, it seems all too likely that we already know what the answer would be.