Register collapse: does a model's prose converge on itself over a long conversation? - All Runs

Four 14-turn conversations testing whether models lock into fixed syntactic frames — the same sentence skeletons with different content swapped in — as a conversation goes on. Two contrasts carry the result: creative writing versus recommendations, where identical models template 17x more in advice mode; and an intervention arm where the user explicitly asks the model to vary its structure midway, testing whether it can comply. Read the per-arm deltas, not the composite.