Three paradigm stages of role-playing language agents

Let me start by situating this in the field's actual research trajectory because it's a story of cumulative progress, not a failure. The survey literature, Chen and colleagues in 2024, Wang and colleagues more recently in 26, trace a clear evolution across three paradigm stages. First, rule-based templates. These are canned responses keyed to inputs. Then imitation. Large models reproducing a figure's voice, cadence, characteristic ticks. And now what the literature calls cognitive simulation. Systems that model personality through psychological frameworks, hold character state and structured memory, and generate behavior through motivational situation chains. Each stage is a genuine advance over the last.