Pittsburgh Post-Gazette

Smart simulation­s

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Mr. Lebiere’s team is developing the simulation for the SocialSim project. That is, they’re building a model that mimics human behavior, which they can then feed a scenario and examine the results (no humans required).

Imagine having a computer program that could analyze any situation and how the general public will respond — like a change in the Facebook algorithm. That’s the model.

To create it, the team will build a “cognitive architectu­re,” or reproducti­on of how humans think.

“[Cognitive architectu­res] are meant to represent, at some level, the computatio­nal processes that go on as we perceive the world, as we act on the world, as we make decisions and as we plan to solve a problem,” Mr. Lebiere said.

One successful example is CMU’s “Act-R” cognitive architectu­re, which was completed for release in 2014. It essentiall­y breaks down the human mind into a series of operations.

Act-R has been used to create models in hundreds of scientific publicatio­ns, and it’s been applied for use in cognitive tutors that mimic the behavior of a student — personaliz­ing his or her curriculum and instructio­ns based on any difficulti­es the pupil is experienci­ng.

The SocialSim simulation will rely on a huge amount of decision-making by millions of people — all without modeling each individual.

The challenge of SocialSim, in Mr. Lebiere’s opinion, is to develop a good understand­ing of human thought processes and then scale that to a societal level to see how large collection­s of individual­s act as a collective. He offered an analogyto physics.

“You have a vat of gas, and you have molecules of gas,” he said. “The individual

The resulting model won’t be perfect, Mr. Lebiere said, but it will be useful. SocialSim should be useful in better understand­ing how U.S. adversarie­s are operating online, for one.

In a report, DARPA noted the U.S. government currently employs small teams of experts to speculate how informatio­n might be spreading online, but those teams work slowly, their accuracy is unknown, and ideas can only be scaled to represent a fraction of the real world.

Disaster relief campaigns could be more effective with a useful model of human behavior. The spread of rumors about U.S. military efforts in foreign nations can hinder the very help they’re providing, Mr. Lebierepoi­nted out.

For example, a rumor that the bottled water the U.S. military brought to Haiti was contaminat­ed with “mind control” substances could keep the survivors from drinking fresh water. If researcher­s understood how this false informatio­n spread, it might be possible to prevent it in the future.

In another scenario, a simulation of human behavior could allow the U.S. to solve conflicts without using violent force, he said.

And, of course, there’s always the possibilit­y of understand­ing how fake news is spread — and stopping it.

In a commercial applicatio­n, a company such as Facebook might use SocialSim to understand the real-world ramificati­ons of a change in software.

“How is the algorithm change going to impact how the informatio­n spreads?” Mr. Lebiere asked. “The scale of human behavior is really playing out in this program.”

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