> using language in a way that requires both a shared world model
Where? What example of GPT-4o requires a shared world model? The customer support example?
The reason GPT-4 does not have any meaningful world model (in the sense that rats have meaningful world models) is that it freely believes contradictory facts without being confused, freely confabulates without having brain damage, and it has no real understanding of quantity or causality. Nothing in GPT-4o fixes that, and gpt2-chatbot certainly had the same problems with hallucinations and failing the same pigeon-level math problems that all other GPTs fail.