In class we have talked about the power that comes from occupying certain locations in a network. Nodes with a lot of edges, or well connected nodes, have a lot of power. Furthermore, we have talked about how edges form. They can form randomly but they are more likely to form between two nodes with a mutual neighbor. This concept is called triadic closure. In networks with positive and negative edges, the signs of the existing edges have a great influence on the sign of newly forming edges.

Our discussions in class regarding the formation of edges has been limited to direct, local influences. It doesn’t even seem likely that the signs on edges between two nodes would influence the sign on a newly formed edge between one of the nodes and a previously isolated node. After all, the isolated node didn’t know either node before. Despite this, there are very real effects on edge formations from nodes that are only connected to one of the nodes. Imagine a social network, for instance, that represents the positive and negative attitudes of high school students toward their peers. Now look at how edges form between a new student and all of the existing students. The new student is far more likely to gain a positive opinion of a given student if most of the other students already have a positive opinion of the given student. This is because people assume that if a person is well liked then that person is probably a person worth liking. It is human nature to emulate each other. However, it would be easy to attribute this particular scenario to factors outside the structure of the network. The charisma of the student that was well liked was likely responsible for why the new edge between the well liked and the new students was positive.

Because of this, we must look at a different scenario. The Presidential elections are a good example. At the beginning of the primary season, Hilary Clinton was so far ahead in the polls for so many states that it looked like only a matter of time before her opponents bowed out of the race. As the primaries began, Barack Obama won a few states. This had very little meaning since Obama had gained only a handful of delegates, except that something started happening to the polls. As Obama won primaries, the polls started shifting in his favor. Clinton won a few primaries towards the beginning but once Obama had won enough states for articles in newspapers to start overstating his growing popularity, the upcoming states shift drastically in his favor. Furthermore, in the Republican race, the early primaries were split between the three major candidates. As soon as John McCain started gaining delegates over the other candidates, however, the polls swung quickly in his favor.

Obviously there are a number of extraneous factors, but there seems to be a very direct influence of perceived opinions on the opinions of others, even when the other people are complete strangers. This is not necessarily confined to human networks. The popular Google search engine returns pages based on how many other pages containing the search criteria link to the returned pages. In other words, the popular pages get returned.