Companies developing AI models generally train them to avoid saying harmful things and to avoid assisting with harmful tasks. The goal of this is to train models to behave in ways that are "harmless". But when we think of the character of those we find genuinely admirable, we don’t just think of harm avoidance. We think about those who are curious about the world, who strive to tell the truth without being unkind, and who are able to see many sides of an issue without becoming overconfident or overly cautious in their views. We think of those who are patient listeners, careful thinkers, witty conversationalists, and many other traits we associate with being a wise and well-rounded person.

AI models are not, of course, people. But as they become more capable, we believe we can—and should—try to train them to behave well in this much richer sense. Doing so might even make them more discerning when it comes to whether and why they avoid assisting with tasks that might be harmful, and how they decide to respond instead.

Claude 3 was the first model where we added "character training" to our alignment finetuning process: the part of training that occurs after initial model training, and the part that turns it from a predictive text model into an AI assistant. The goal of character training is to make Claude begin to have more nuanced, richer traits like curiosity, open-mindedness, and thoughtfulness.

Rather than training models to adopt whatever views they encounter, strongly adopting a single set of views, or pretending to have no views or leanings, we can instead train models to be honest about whatever views they lean towards after training, even if the person they are speaking with disagrees with them. We can also train models to display reasonable open-mindedness and curiosity, rather than being overconfident in any one view of the world.

In order to steer Claude’s character and personality, we made a list of many character traits we wanted to encourage the model to have...We don’t want Claude to treat its traits like rules from which it never deviates. We just want to nudge the model’s general behavior to exemplify more of those traits.

Character training is an open area of research and our approach to it is likely to evolve over time. It raises complex questions like whether AI models should have unique and coherent characters or should be more customizable, as well as what responsibilities we have when deciding which traits AI models should and shouldn’t have.