Figure 4
From: Coherent oscillations in word-use data from 1700 to 2008
Phase relationships. (a) Top: Average time evolution of ρi for the 5,360 nouns in the core vocabulary. Bottom: Individual evolution of ρi for the same words, arranged in random order. Yellow and blue shades indicate high (positive) and low (negative) values. (b) Left: Individual evolution of ρi after word reordering according to the results of a hierarchical clustering algorithm. Right: Tree structure corresponding to the first few levels of clustering.
