A causal factorial-intervention test confirms OCEAN trait directions compose approximately independently in a real LLM

Feng, Zhao, Zhong, Huang, Gu, Kong, Feng & Qin extract diff-of-means OCEAN personality-trait directions in real Qwen2.5-7B-Instruct, reporting a cosine-similarity heatmap across 10 trait-pole vectors (e.g. Calm-Dependable +0.751, Calm-Careless -0.714) [feng-etal-2026-persona-dynamic-compositional-inference-time-control] A causal factorial steering experiment measures one trait's behavioral shift when a second trait is simultaneously steered, finding cross-trait effect sizes an order of magnitude smaller than same-trait effect sizes (Delta E <= 1.2 vs Delta A 5.0-7.4, an approximately 8.8:1 ratio) [feng-etal-2026-persona-dynamic-compositional-inference-time-control] Vector-arithmetic composition of the extracted trait directions achieves up to 91 percent win rate on a Persona-Evolve compositional-control benchmark [feng-etal-2026-persona-dynamic-compositional-inference-time-control]