In his new book, ALEX PENTLAND is on a mission to understand communication and decision-making — one idea at a time.

The way ideas spread through our social network determines our behavior, argues Alex Pentland in his new book, Social Physics: How Good Ideas Spread — The Lessons From a New Science (Penguin Press, $28). The director of the Massachusetts Institute of Technology (MIT) Human Dynamics Laboratory and the MIT Media Lab’s Entrepreneurship Program, Pentland was named one of the “seven most powerful data scientists in the world” by Forbes in 2011. “Big data,” he tells American Way, “has allowed us to understand ourselves.”

In fact, Pentland says that for the very first time, we can garner enough data about human behavior to build a predictive science that helps us understand how ideas come into being and how they spread. Pentland’s research shows that much decision-making is based on social context. Thoughts and ideas are passed between people and groups — what he calls “idea flow” — in a way similar to how a virus spreads. In order to create a healthy environment for idea flow, engagement is critical. “Is there enough conversation­ within the community?” Pentland asks. “If the conversation is rich enough, people come to a common understanding.”

It’s also important to be wary of the echo-­chamber effect; a variety of ideas is critical. “In a healthy community,” he says, “there’s internal conversation as well as external conversation.” In our increasingly connected world, it’s important to not underestimate the power of face-to-face communication. Online social interactions “help exploration, but don’t help engagement,” he says. “Most of what we do comes from people we hang out with.”

By studying the patterns of flow, Pentland draws implications to a range of large-scale arenas — from the global economy to political activism to public health. “Being able to stop flu pandemics and make trains run on time is one thing,” he says. “But by understanding how people make decisions, we can make governments run more smoothly. Our current government is built on the social science of the 1700s. It was good then, but we can do a lot better today.”