The Harry Potter saga and the small world network

Is Harry Potter the protagonist of the saga that bears his name? Are the characters we all remember from the films of The Lord of the Rings those really having more weight in the books? Is Paul Atreides the central axis of Dune?

These questions were asked by the master students of Complex Systems Physics from the Institute of Interdisciplinary Physics and Complex Systems (IFISC), a joint research center between the University of the Balearic Islands (UIB) and the Higher Council of Scientific Research (CSIC). The students used complex networks, data analysis and big data techniques.

On Monday, February 6, IFISC celebrated its 4th Poster Party, an event in which the IFISC researchers presented in a relaxed atmosphere their work in poster format. Taking advantage of the occasion, the students of the master's degree that the center offers, presented a poster entitled Analysis of communities in literary social networks. In their work, the students generated an algorithm with the following goal: it detected every time the name of a person appeared. If in the next 15 words the name of another character appeared, a bond between them is created. These data allow them to obtain the necessary information that characterizes the social networks of a population. Thus, one can see which characters are related to each other in addition to the intensity of that link, depending on the number of times they are named together.

With these simple but powerful rules the students analyzed the complete sagas of Harry Potter and The Lord of the Rings, in addition to the first three Dune novels. In the generated networks it is possible to observe how the main characters have bigger nodes (this means a greater number of apparitions), as well as to verify that within the novels there are communities in which the members have more relation between them than with other characters (represented with nodes and links of different color).

In the case of Harry Potter novels, for example, it can be seen how the Harry, Hermione and Ron nodes are by far the largest, forming a small group with many interactions between them (thicker bonds). Also we can observe different secondary communities: the Weasley family (in brown color) forms a separated community of the Death Eaters, Harry Potter (the protagonist of the saga) being the central node, i.e., the point of connection between different communities.

The study concludes that the fictional social structures of novels follow what is called a small world structure. In this network model, there are separate groups of nodes with a large number of connections to each other (communities); but in turn the communities are connected through links between certain members. Small world networks have the property that any member of the network can be connected to another with a small number of steps. These networks can be observed in the real world, where the famous hypothesis of the six degrees of separation tells us that we can connect any pair of people in the world via only six intermediate steps.

Due to their effort and originality, the work of the master students was awarded by a popular vote from IFISC members as the winner of the Best Poster of the 4th Poster Party.

The IFISC Complex Systems Physics Master is offered by the Universitat de les Illes Balears (UIB) in collaboration with the Higher Council for Scientific Research (CSIC), organized and taught by the Institute of Interdisciplinary Physics and Complex Systems (IFISC).

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