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Princeton Weekly Bulletin   June 4, 2007, Vol. 96, No. 28   prev   next   current

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  • Editor: Ruth Stevens

    Calendar editor: Shani Hilton

    Staff writers: Jennifer Greenstein Altmann, Eric Quiñones

    Contributing writers: Chad Boutin, Hilary Parker

    Photographers: Denise Applewhite, John Jameson

    Design: Maggie Westergaard

    Web edition: Mahlon Lovett

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Princeton scientists to study group decision-making by the numbers

By Chad Boutin

Princeton NJ — For the next five years, Princeton researchers will be exploring ways to help groups make better collective decisions — especially when those groups include machines as well as people.

Scientists from several campus departments will participate in two related projects that aim to create new computer models of group decision-making, a process whose intricacies have never before been quantified. Two grants, both funded by the U.S. Air Force’s Multidisciplinary University Research Initiative and spread among researchers at several universities, will provide Princeton with a share of several million dollars to model how people think when they think together.

But the effort will go beyond elucidating collective decision-making in gatherings of humans alone. Because society increasingly employs groups of autonomous machines — from the networked computers that power Internet search engines to the fleets of unmanned aerial vehicles that fly reconnaissance missions for the military — the scientific team will investigate the interactions between these electronic brains as well.

Scientists from several campus departments will participate in two relatedprojects that aim to create new computer models of group decision-making, a process whose intricacies have never before been quantified.

Ultimately, the effort to model these different kinds of distributed thought may one day lead to common insights about collective behavior, perhaps allowing organizations to better delegate aspects of the decision-making process. Psychology professor Jonathan Cohen said the team’s desire is to create mathematical models of social interactions that are informed by what researchers know about decision-making in the brain.

“Psychologists have studied social behavior, and neuroscientists have had some success modeling the interactions in an individual brain without considering the influence of other people on it,” said Cohen, co-director of Princeton’s new Neuroscience Institute. “We’re bringing them together for the first time.”

This effort will mingle experts from fields as diverse as neuroscience, engineering, social psychology and applied mathematics to achieve its goal. The team’s first step will be to take some time-tested psychological experiments on decision-making in individuals and modify them in order to gather data on how people’s decisions can change when others are around.

“Making decisions by oneself can be difficult enough,” said team member Deborah Prentice, professor and chair of psychology. “However, a social setting brings in a dizzying number of factors that further complicate the decision-making process, such as biases toward one’s teammates and the pressure on the individual to conform with the opinions of higher-ranking group members.”

Tracking such a vast number of interwoven phenomena demands powerful computation of the sort scientists might use to predict the weather. Mathematical models can approximate the shifting interplay of ocean currents, wind and cloud cover on the planet, and the Princeton group hopes that similar approximations can help them understand the interplay of people on the planet as well.

Though the team is still discussing the best way to approach this highly complex problem, they have reason to believe it is possible, because scientists have already had some success with creating mathematical models of the way cells in an individual brain work together.

“Making decisions by committee can be a complicated process, but it’s something your brain cells do all the time,” said Philip Holmes, professor and chair of mechanical and aerospace engineering, who specializes in mathematical modeling. “They also consult one another and arrive at decisions, which come out as your thoughts and urges. We hope to modify and extend existing models of decision-making among neural cells so they can be applied to humans working in groups.”

Princeton’s scientists are well suited to contribute psychological expertise to the effort, in part because of the Neuroscience Institute’s growing experience with interdisciplinary work. And though the eventual results will likely have a broad range of applications, there are projects here on campus that will benefit from the findings — particularly the effort of Naomi Leonard, a professor of mechanical and aerospace engineering, to explore an undersea canyon with a fleet of autonomous submarine robots.

“Ideally, this research will help reveal the best ways for teams of humans and robots to work together,” said Leonard, whose ongoing work with the submarines was instrumental in motivating the Princeton team to take on the new projects. “Getting a group of humans with diverse expertise and personalities to work together with a group of robotic vehicles can be tough unless you know the best way to divide up the decision-making among them. We hope to develop improved math models of the robots’ collective effort, then try to make human interactions better by applying what we learn from the vehicles, and vice versa. It will be a two-way conversation.”

While the Air Force will likely find use for the results in coordinating its own unmanned aerial vehicles with their human operators, Holmes said that the findings will be relevant across civilian society.

“We all live in a world in which autonomous machines are going to be making a lot of our decisions, just as a search engine selects what websites you’re likely to visit when you type a query,” he said. “Our decisions are very much connected with the technological web all around us, and this notion of studying groups of people and groups of vehicles is a rather well-defined case of that.”


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