Identity Crisis: How a Trivial Trick Teaches LLMs to Think Backwards
Opening — Why this matters now Large language models can write poetry, solve Olympiad-level math problems, and simulate entire businesses—yet they reliably fail at a task that feels almost insulting in its simplicity: if Alice’s husband is Bob, they struggle to answer who is Bob’s wife? This failure mode, known as the reversal curse, has become something of an embarrassment for autoregressive models. More troublingly, a growing body of literature has argued that the curse is fundamental: a baked-in limitation of left-to-right next-token prediction. If true, this would place a hard ceiling on what today’s LLM architectures can ever reliably reason about. ...