I'm also looking for the psychological elements that fuel commodity culture. For example, if we imbue girls with deep insecurity about their bodies through images of an impossible ideal, we create a really vulnerable and avid consumer. If somebody feels that they're not OK without a certain product, you have a very deep and loyal market that will come back to the product again and again. Sometimes, this process is both rational and irrational.

When I first moved from photography to filmmaking, I was worried about how big I had to become. I was one person, or maybe me and an assistant, and I had these small cameras, and maybe a flash.

The 1970s were the height of social mobility. College was accessible. My grandfather was a poor immigrant who went to a public school in Ohio, and my father went to Harvard. That wasn't unusual. There was a feeling that anything was possible and you didn't have to be born into money to have a successful life. Now, people don't believe in the idea that anything is possible. We have more inequality than we've had ever before and a greater concentration of wealth in the hands of a few.

I've often used the extremes in my work to comment on the mainstream. I think that sometimes a subject that I'm working on, like popular culture, is so present all around us that they're hard to see. It's like: How do you see the air you breathe? How do you see how it affects you?

These days, the media is defining what cultural capital is, and it's easily learned. If you have money, anything can be bought. We see this in China and Russia with what I call the "Bling Dynasty and New Oligarchy" in Generation Wealth. As people got rich and everybody started buying Louis Vuitton bags, it became clear that to distinguish yourself you had to have more than an expensive bag. People began to want the things that money is not supposed to be able to buy - history, tradition, education, and culture.

The economist Juliet Schor talks about how our reference group has changed over the last twenty-five years. As we spend less time with our neighbors, we're spending more time with people we know from TV and social media, and this becomes our new reference group. The media is full of images of people with wealth, and we're comparing ourselves to them and aspiring to what they have. Instead of keeping up with the Joneses family, we're trying to keep up with the Kardashians, even though it's completely unrealistic.

Hip-hop has been so important in my work, because it speaks to the idea of money being tied to cultural capital in an honest and transparent way. When I was growing up in LA, money was equivalent to class, and it was a passport. Hip-hop emphasizes that, but Hollywood and show business bear it out. If you have money, there really is no barrier to social mobility. There are still social clubs in Newport where you can't get in even if you have money, but that is really rare.