New analysis of networks reveals surprise patterns in politics

May 24, 2006

A new computer analysis technique developed at the University of Michigan that separates networks into communities yielded some surprises when used on real-world networks like political books, blogs, and metabolic systems.

For instance, researchers used the algorithm to sort books sold on Amazon.com into left- and right-wing groups, and they found the book most appealing to conservatives was actually written by Democrat Zell Miller.

Miller, the former governor of Georgia and U.S. senator, angered Democrats by endorsing George Bush during the last presidential election. Miller's book, "A National Party No More, The Conscience of a Conservative Democrat," was the book most central to the community of conservative book buyers, according to researchers.

A network is a system of nodes connected by links and the nodes sometimes divide into groups or communities, said U-M physics associate professor Mark Newman, who developed the technique. By analyzing these groups, scientists better understand the structure and function of the network. Although methods for detecting groupings in networks have been proposed before, the U-M technique performs it faster and more accurate than other methods, Newman said. It also adds a new element to the analysis: it weighs how tightly members are bound to their groups, which can affect their functions or the roles that they play.

In the example of political books, Newman looked at 105 political titles recently sold on Amazon.com. The network was compiled by Valdis Krebs, a management consultant friend of Newman's, who looked up each book and noted which books were commonly purchased by the same buyers---information that Amazon includes on its website. The links in the network represent purchasing connections between books.

When analyzed using Newman's method, the network of books separated into four communities, with dense connections within communities and looser connections between them. One community was composed almost entirely left-wing books, and the other almost entirely of right-wing ones. Centrist books comprised the other two categories. The computer algorithm doesn't know anything about the books' content---it draws its conclusions only from the purchasing patterns of the buyers---but Newman's analysis seems to show that those purchasing patterns correspond closely with the political slant of the books.

"It is particularly interesting to note that the centrist books belong to their own communities and are not, in most cases, merely lumped in with the liberals or conservatives," the paper stated. "This may indicate that political moderates form their own purchasing community.

In another example, Newman used the algorithm to sort a set of 1225 conservative and liberal political blogs based on the network of web links between them. When the network was fed through the algorithm, it divided cleanly into conservative and liberal camps. One community had 97 percent conservative blogs, and the other had 93 percent liberal blogs, indicating that conservative and liberal blogs rarely link to one another. In a further twist, the computer analysis was unable to find any subdivision at all within the liberal and conservative blog communities.

"This behavior is unique in our experience among networks of this size and is perhaps a testament not only to the widely noted polarization of the current political landscape in the United States, but also to the strong cohesion of the two factions," the paper stated. The network of blogs was compiled by another U-M professor, Prof. Lada Adamic of the U-M School of Information.

Newman's methods have also been adapted by researchers working in molecular biology to study metabolic networks, the chemical networks that power cells in human and animal bodies. In a recent paper in the journal Nature, researchers Roger Guimerà and Luis Amaral from Northwestern University in Evanston, Ill., found that metabolites that straddle boundaries between groups in metabolic networks show persistence across species. Commenting on the work of Guimerà and Amaral, Newman says that this could be a sign that the division of the network into modules corresponds to different roles that metabolites play within the cell, and could suggest new directions for interpreting data on biochemical networks.

Newman's findings will appear in the June 6 print issue of the Proceedings of the National Academy of Science, in a paper entitled "Modularity and community structure in networks."

Source: University of Michigan

Explore further: New study shows plants can learn from experience

Related Stories

New study shows plants can learn from experience

December 7, 2016

The first time I met the Australian evolutionary ecologist Monica Gagliano, she was wearing colourful paisley trousers and was giving an animated talk at a 2014 environmental humanities conference in Canberra.

Parenting classes benefit all, especially lower-income families

December 5, 2016

Parenting education can improve the skills of every mom and dad and the behavior of all children, and it particularly benefits families from low-income or otherwise underserved populations, a new study from Oregon State University ...

Fiction books narratives down to six emotional story lines

November 21, 2016

Our most beloved works of fiction hide well-trodden narratives. And most fictions is based on far fewer storylines than many have imagined. To come to this conclusion, big data scientists have worked with colleagues from ...

Targeting brain chemistry to beat disease

November 17, 2016

Thanks to advances in big data and medicinal chemistry, scientists can screen thousands of molecules in the search for protein structures leading to new drugs for brain diseases.

Recommended for you

Uncovering the secrets of water and ice as materials

December 7, 2016

Water is vital to life on Earth and its importance simply can't be overstated—it's also deeply rooted within our conscience that there's something extremely special about it. Yet, from a scientific point of view, much remains ...

Blocks of ice demonstrate levitated and directed motion

December 7, 2016

Resembling the Leidenfrost effect seen in rapidly boiling water droplets, a disk of ice becomes highly mobile due to a levitating layer of water between it and the smooth surface on which it rests and melts. The otherwise ...

The case for co-decaying dark matter

December 5, 2016

(Phys.org)—There isn't as much dark matter around today as there used to be. According to one of the most popular models of dark matter, the universe contained much more dark matter early on when the temperature was hotter. ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.