A toy clustering of public-facing thinkers by the "genome" of beliefs they publicly profess. Each person is a presence/absence vector over a fixed trait set; the tree is UPGMA (Unweighted Pair Group Method with Arithmetic mean) over Hamming distance. Switch the dataset below to swap communities. Categories drive the cell colors; pattern overlays flag hitchhiking traits and crossover individuals.
The data model. Each thinker is a presence/absence vector over a fixed trait set. Traits are grouped into categories (shown above the heatmap) that color the cells. Strength of belief, recency, and context are all flattened to a single bit.
The distance metric. Pairwise distances are Hamming distances: count the traits where two people differ, weight each trait equally. No normalization or IDF reweighting. The PCA panel below is a separate view, not folded into the tree's distance.
The clustering. The dendrogram is built by UPGMA, an agglomerative average-linkage algorithm. It runs client-side on page load over the inline data; editing the inline arrays in the page source would recompute the tree.
Pattern overlays. "Hitchhiking" is a loose nod to genetic hitchhiking; strictly, the pattern is linkage: traits that co-occur often enough that one predicts the others. Whether selection is doing the dragging here is left to the reader. "Crossover" cribs from chromosomal crossover: individuals who recombine traits across otherwise linked clusters. Each bundle below is anchored on a single individual in this slice; the overlays are layered on top of the tree, not computed from the data.
PCA collapses the trait matrix to the directions of largest variance. PC1 is the strongest axis of belief divergence; PC2 is the next-strongest orthogonal direction. Hitchhiking clusters appear as labeled centroids over the people who carry at least half their traits. Solid amber dots are full carriers (every trait in the bundle); hollow amber dots are partial carriers (at least half, but not all). Clusters with only one carrier skip the centroid label, since it would sit on the anchor's dot. Click a cluster pill above to emphasize its members; click a centroid to do the same.
Trait bundles that travel together when they appear at all. Click a bundle to highlight its traits in the heatmap above.
Unexpected recombinations: people who pair traits from clusters that otherwise rarely mix.