Fig. 5. Time series of political alignment.

Negative alignment scores mean Left-leaning and positive scores mean Right-leaning. Alignment scores s_h are calculated from content to which drifters are exposed in their home timelines, based on hashtags (a) and links (d). Alignment scores s_u are calculated from content expressed by the drifter posts in their user timelines, based on hashtags (b) and links (e). The difference s_h − s_f measures news feed bias experienced by drifters, where the political alignment score s_f is derived from the content generated by friends, based on hashtags (c) and links (f). Missing values are replaced by preceding available ones. Colored confidence intervals indicate ± 1 standard error. Source data are provided as a Source data file. Plots for each individual drifter are in Supplementary Figs. 2–4.