Eurovision and neighbourhood

When distances matter more than music...

(in French)

Every year during the Eurovision evening, when the scores are announced, one can notice that countries are frequently voting for their nieghbours. Let's check this tendency by building the phylogenetic tree of European countries according to their Eurovision votes, which moves closer country which voted in a similar way.

More accurately, if we consider two countries, P₁ and P₂, and call Points_i(j) the number of points given by country P_i to country P_j, one can compute the Eurovision-distance between two countries P_i et P_j in the following way :
Σ Country P_k | Points_i(k) - Points_j(k) |

From the original pdf (semi-finale, finale), transformed into a CSV table (semi-finale, finale), the distance matrix obtained is then coded into the nexus format (semi-finale, finale), and the resulting file provided as an input of Splitstree, a program which reconstructs the phylogenetic tree useful to visualize, in a same subtree, countries which voted in a similar way.

Phylogenetic Tree of the Finale of Eurovision 2006

Phylogenetic tree of European countries according to their vote in the finale of Eurovision 2006,
built with Splitstree 4 [3], the BioNJ algorithm [2], then a Daylight Optimization [1] for the
layout of the tree. One can notice the grouping of Nordic, Baltic countries, and ex-Yugoslavia.
"Europe" represents the average amongst all european countries.

Phylogenetic Tree of the semi-finale of Eurovision 2006

Phylogenetic tree of European countries according to their vote in the semi-finale of Eurovision 2006,

Even if the tree doesn't move closer every geographically close countries, some groupings reflecting geographycan be observed, and apparently Europeans have not reached communion in music evaluation. Let's not be pessimistic in interpreting these biases as support votes to neighbors, but let's just invoke regional harmonies in musical tastes.

Any comments or suggestions?

Bibliography

[1] P. Gambette, D.H. Huson: Improved layout of phylogenetic networks, to appear in TCBB, 2006.
[2] O. Gascuel: BIONJ: an improved version of the NJ algorithm based on a simple model of sequence data, Mol. Biol. Evol, 1997.
[3] D.H. Huson and D. Bryant: Application of Phylogenetic Networks in Evolutionary Studies, Molecular Biology and Evolution, 23(2):254-267, 2006, software available from http://www.splitstree.org.