Suppose scientists discovered a clump of neurons in the brain that, when stimulated, turned people into egalitarians. This would be good news for Democratic strategists and speechwriters, who could now get to work framing arguments about wealth and taxation in ways that might activate the relevant section of cerebral cortex.

This “share-the-spoils” button has been discovered, in a sense, but it may turn out to be harder to press than Democrats might think.

Pretend you’re a three-year-old, exploring an exciting new room full of toys. You and another child come up to a large machine that has some marbles inside, which you can see. There’s a rope running through the machine and the two ends of the rope hang out of the front, five feet apart. If you or your partner pulls on the rope alone, you just get more rope. But if you both pull at the same time, the rope dislodges some marbles, which you each get to keep. The marbles roll down a chute, and then they divide: one rolls into the cup in front of you, three roll into the cup in front of your partner.

This is the scenario created by developmental psychologists Michael Tomasello and Katharina Hamann at the Max Planck Institute in Leipzig, Germany. In this situation, where both kids have to pull for anyone to get marbles, the children equalize the wealth about 75% of the time, with hardly any conflict. Either the “rich” kid hands over one marble spontaneously or else the “poor” kid asks for one and his request is immediately granted.

But an experiment must have more than one condition, and the experimenters ran two other versions of the study to isolate the active ingredient. What had led to such high rates of sharing, given that three-year-olds are often quite reluctant to share new treasures? Children who took part in the second condition found that the marbles were already waiting for them in the cups when they first walked up to the machine. No work required.

Read more at New York Times.