Dan Ariely and Michael Norton's 2011 study on wealth inequality went viral on YouTube this week. It's a beautiful piece of work. First, they asked Americans what their ideal distribution of wealth would be. The answer? Much more equal. Then they asked Americans what they thought the actual distribution of wealth was. Less equal than their ideal, came the answer. But the truth, as Ariely and Norton noted, was that America was much less equal even than that. Reality was twice as far from the average American's ideal as the average American thought. When we talk about economic inequality, we tend to talk about income inequality. But wealth inequality is much more skewed. The top 1 percent has about twice as large a share of the national wealth as it does of national income. There's a strong case to be made that what we worry about when we worry about economic inequality makes much more sense in terms of wealth than income. And then there's the role of wealth in creating income inequality. One thing we've seen in this recession is that financial assets have recovered much more quickly than wages or housing. Moreover, gains from financial assets are taxed much more lightly than traditional income. So if the income from financial assets is spread very unevenly, that will have a magnifying affect on income inequality. Here's what you should know about wealth inequality in the United States: It's worse than Americans want it to be, much worse than they think it is, and it's increased over the last few decades. Which is one reason that there's been more talk of a wealth tax lately.