Personality training shapes a model’s stable behavioral character: its personality, values, and manner of responding. Unlike an inference-time prompt, it changes model weights to establish a base persona. section 17.1
Prompting versus character training
A prompt can request, “Acting as a burned out employee, write me an email summarizing my last month of work.” Character training instead aims to make the desired manner a persistent model behavior. section 17.1
Implementation commonly combines familiar post-training methods with precise control over behavioral language:
- Fine-tune on personality-specific data; this is described as more robust than prompting and stronger than activation steering for character traits. section 17.1
- Filter training data and use synthetic-data methods such as constitutional AI to control response manner, including recurring phrases and assistant framing. section 17.1
- Use preference optimization and other post-training methods to craft specific traits, while recognizing that effects on user preferences and benchmarks remain difficult to measure. section 17.4
The target is primarily how a model responds rather than what information it provides. Relevant tradeoffs remain unsettled, including how to study character changes and how they affect user-facing metrics. section 17.1
