Most intrinsic association probes operate at the word, sentence, or corpus level, obscuring author-level variation. We present POLAR (Per-user On-axis Lexical Association Re-port), a per-user lexical association test that runs in the embedding space of a lightly adapted masked language model. Authors are represented by private deterministic to-kens; POLAR projects these vectors onto curated lexicalaxes and reports standardized effects with permutation p-values and Benjamini--Hochberg control. On a balanced bot--human Twitter benchmark, POLAR cleanly separates LLM-driven bots from organic accounts; on an extremist forum,it quantifies strong alignment with slur lexicons and reveals rightward drift over time. The method is modular to new attribute sets and provides concise, per-author diagnostics for computational social science. All code is publicly avail-able at https://github.com/pedroaugtb/POLAR-A-Per-User-Association-Test-in-Embedding-Space.
@article{arxiv.2603.15950,
title = {POLAR:A Per-User Association Test in Embedding Space},
author = {Pedro Bento and Arthur Buzelin and Arthur Chagas and Yan Aquino and Victoria Estanislau and Samira Malaquias and Pedro Robles Dutenhefner and Gisele L. Pappa and Virgilio Almeida and Wagner MeiraJr},
journal= {arXiv preprint arXiv:2603.15950},
year = {2026}
}