This is a guest post by Duke political scientist David Siegel.

We’ve heard a lot about how economic elites – the so-called 1 percent — have greater policy influence than the mass public and more access to the seats of political power. The recent Supreme Court ruling regarding campaign contributions (McCutcheon v. FEC) would seem to exacerbate this trend (though see this), removing still more limitations on the influence of the rich. The continuing accumulation of capital in the hands of the rich will only make this problem starker.

Given this, why haven’t we as citizens in a democracy done something about it? After all, most of us are not rich and, as political scientist Larry Bartels notes here, we usually think of democracy as a system in which the elected officials who pass the laws must satisfy us, the people.

Political scientists Kenneth Scheve and David Stasavage offer four reasons here for why democracy has not saved us from inequality. They end with the one to which they appear to give the most credence: mass opinion. In short, for democracy to reduce inequality, it must be the case that people view progressive taxation as necessary to ensure fairness. Put another way, democracy hasn’t saved us from inequality because people don’t sufficiently want to reduce inequality.

Why might this be? I’ve explored one answer to this question, which I’ll term “feedback in opinion formation.” Everyone who’s ever held a microphone too close to a speaker knows what feedback is. It turns out that the same mechanism is at play in how we all form opinions, thanks to the degree to which our choices are all connected.

One can see how this works with a simple thought experiment. Let’s say all of us made our decisions in a vacuum. How would economic elites influence our opinions? Well, they’d have to use the media to sway enough of us individually over to their side so as to form a majority.

That’s pretty hard; how would the media know the precise arguments and appeals that would get people to listen to them? What might convince 10 percent of the people might be worthless, or even counterproductive, in convincing a different 10 percent. Then there’s the problem of the media’s getting us to pay attention to them in the first place. All in all, one might imagine a pretty uphill battle.

But this is not how most people come to decisions. There’s lots of evidence that we are deeply social thinkers, engaging in discussions with family, friends, co-workers and neighbors about all sorts of things that help us to form our own opinions.

It turns out that this can have a big effect on the incentives of economic elites. Rather than having to reach us all individually, they can work on only some of us. Maybe only a few people will be swayed directly by the media, but those who are will talk to others. And in doing so, these converts will take advantage of interpersonal trust and knowledge of the kind of arguments and appeals that work on friends and family to move their thinking as well.

Now — and here’s the feedback — these same people moved by the arguments and appeals will become more susceptible to the media’s message. If they become convinced, they’ll add their voices to discussions among their own friends and family. And so on. Eventually the process can swing public opinion.

This is not a problem if the media is an honest broker, but when it evinces actual bias, even a little bit of bias can lead to massive swings in public opinion. As long as this biased media is credible among some people, lots of people can be indirectly convinced by their social networks to believe its message.

As I show here, this feedback process is easier to get going when you’re advocating against the status quo. But what’s been the status quo among many democracies for the latter half of the 20th century? The modern welfare state and a progressive tax system. So not only does feedback allow mass shifts in opinion, it has been over the past few decades particularly good at driving opinion away from established mechanisms to reduce inequality. Little wonder then the recent success of elites.