IBM’s “Project Debater” made history as the first AI machine to make a persuasive argument about a given a topic it had not been programmed to learn.

On Monday, February 11, Harish Natarajan, which holds the world record for most international debate victories, prevailed in his debate against IBM's AI machine. But the debate was the most unusual—and perhaps the most challenging—he’s ever had. After all, Project Debater had access to 10 billion sentences in hundreds of millions of documents. Natarajan had no access to the Internet. He just had a pen, his notepad and his brain.

Each side—human and machine—had 15 minutes to prep for the debate.
They were each presented with a topic: "Should we subsidize preschools." Project Debater had to argue in support of it. Natarajan had to argue against it. Once again, he only his brain, persuasion skills and a human ability to connect with an audience.

IBM’s AI machine went first. She presented a reasoned, logical 4-minute case to support her opinion. She focused on three areas: preschool boosts a child's academic achievement, it helps to overcome poverty, and it results in a decrease in crime. The machine scanned millions of documents, retrieved the relevant messages to support its opinion, and presented scores of studies and empirical research to back its argument.

According to scientists who worked on the project, the achievement is nothing short of extraordinary. Project Debater structured an argument, only presented evidence to support its case, listened to Natarajan’s argument and formed a rebuttal.

Natarajan used a more nuanced form of persuasion—one that would resonate with fellow humans. Natarajan said that great persuaders find common ground with their opponents. And that’s exactly what he did.

“First, I’d like to focus on what agree on,” he began. “Poverty is terrible. It is also terrible when people don’t have running water or healthcare to cover their child…”

Natarajan used his time to argue that, while funding preschool is a laudable goal, we live in the real world of financial constraints and there’s a limit to how much we can spend. He argued that Project Debater’s position would hurt the very people it intends to help by re-directing scarce resources from other worthy initiatives.

At the end of the debate, the live audience of 800 guests were invited to vote. Since more people said that Natarajan had turned around their pre-formed opinions, he was declared the winner. After all, the point of debate is not to score the most points. It’s to sway a person’s opinion.

IBM’s AI machine wasn’t built to ‘win’ or replace humans. It was built to complement human decision-making. According to the research team that built the machine, it’s meant to enhance communication with evidence and reason. No, AI doesn’t have emotion. It can’t read an audience or connect to people on an emotional level. But it can structure reasonable arguments backed by millions of studies, documents and empirical evidence.

Project Debater’s arguments were “nicely phrased and contextualized…better than most humans” Nataraji told me after the debate. “It has incredible power to complement the human."