A longitudinal convergence between a user's communication style and the AI's responses over repeated exchanges, in which the pair settles into a shared workable register; a stylistic adaptation, not an emotional state of the AI.
Tracked as decreasing stylistic distance between user and AI turns across a session series, measured on linguistic style features; the trend is the downward trajectory of that distance over time.
Proposed measurement protocol (not yet empirically validated): Stylometric convergence: per-session linguistic distance between user and AI turns (function-word and register feature vectors, cosine or Euclidean) tracked over sessions, with the distance trajectory as the outcome.