In each year we plotted on the maps of the United States of America colors according to the method explained in the text. States that share similar colors have also a similar distribution of the baby names. This notion of similarity comes from the Principal Component Analysis (PCA).
While Northern and Southern states belong to two distinct cultural areas in the first decades of the century, a new configuration of states emerges at the end of the twentieth century, where central and coastal states (with very long range correlations covering thousands of miles of physical distance) are roughly part of two different cultural areas. We performed the analysis explained in Methods both for girls SV1 and boys SV2.
Hierarchical clustering of the states in every year. This video reflects the analysis of the previous video, and provides, through a different method, the same informations about the evolution of the cultural areas of the United States of America. Details on the clustering method are given in the full article. The social evolution of geographical correlations are very clear. Also in this case we repeated the analysis both for girls SV3 and boys SV4.
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