Identity Diversification and Homogenization: Evidence from Frequent Estimates of Similarity of Self-Authored, Self-Descriptive Text

For more than a decade, individuals composed and edited self-authored self-descriptions as social media biographies. Did these identities become more diverse over time because of a "rise in individualism" and increasing tolerance or did they become more homogenous through social learning, conformity, and fear of isolation? We analyzed longitudinal and cross-sectional Twitter bio samples with a variety of lexical and semantic methods for the 2012-2022 interval. We show that longitudinally, users diversified on lexical and semantic levels. On a cross-sectional sample - representing the state of the platform at any time point – we again observed a trend of diversification at the lexical level, but a trend of diversification reversed toward re-homogenization on the semantic level. Further, by focusing on local maxima and minima of identity similarity we identified “coordination shocks” - temporally confined intervals where similar users became overactive on the platform and drove short-term deviations from longer-term trends.