Former Cambridge Analytica research director Chris Wylie became famous this year for exposing the psychological-influence tactics his company used to try to sway the 2016 U.S. presidential election. Now he’s educating the public on how these tactics work, laying the groundwork for people to better arm themselves against undue influence.

Wylie’s role at Cambridge Analytica was to take traditional military “information operations,” or information warfare, and translate them into digital operations. Historically, in military offensives waged against groups like narcotics cartels in South America, operatives would plant people in organizations to infiltrate them.

“One thing you want to do is identify the type of person you could exploit and undermine them psychologically,” Wylie told Forbes reporter Thomas Brewster onstage at the Forbes 30 Under 30 Summit in Boston. “You’d find people who were less resilient psychologically… you essentially tried to exacerbate distrust and paranoia.”

In the old days, this had to be done manually, person-by-person. But with Facebook, you can do it digitally, on a much larger scale. For example, with a fake Facebook profile, operatives can develop relationships with people online, Wylie said. They can feed them comments that affirm their thinking, giving the false impression that there are many more people who think the same way.

And even more frightening, they can carry that influence into in-person interactions, Wylie said. Let’s say an organization knows that only 5% of people who are invited to an event on Facebook actually attend. If they invite 1,000 to 2,000 people to an event at a local coffee shop, 50 to 100 might show up and crowd the place.

“All of a sudden, this online fantasy gets translated into a very tangible reality,” Wylie said. “They look around and see all these people who look and sound like them, talking about things they’ve been thinking about. They begin to get this idea that there is a movement happening.”

Wylie added, “In the military, that would be called insurgency building. In the U.S. in politics, that’s called the alt right.”

At Cambridge Analytica, Wylie led research that helped enable these types of manipulations. And when did he decide he had had enough and to become a whistle-blower? “The idea that you’re treating voters in the same way that you’d treat a terrorist” made him change his mind, he said.

When you’re engaging in information warfare, “the agency and autonomy of those people is not a consideration,” he said. “It’s fair game to deceive, undermine, exploit, manipulate and coerce. To take that approach and to then apply that to a democratic system, where the reason why democracies have legitimacy in the first place is because people have autonomy and agency … that is inherently undemocratic.”