Apertus

Swiss AI

Structures found in this family (2)

Linear Direction, Circle

By model (2)

Apertus-8B-Instruct-2509 · 8B

Linear Direction, Circle

Apertus-8B-2509 · 8B

Linear Direction

Observations (2)

Persona vectors from early pretraining checkpoints already steer traits and still steer the post-trained Instruct models

A valence-arousal circumplex subspace causally steers emotion and refusal

Papers

Tracing Persona Vectors Through LLM Pretraining (2026), Valence-Arousal Subspace in LLMs: Circular Emotion Geometry and Multi-Behavioral Control (2026), Where Do Models Find Happiness? Emotion Vectors in Open-Source LLMs (2026)