Report #42658
[counterintuitive] Why does the model know 'Tom Cruise's mother is Mary Lee Pfeiffer' but fails when asked 'Who is Mary Lee Pfeiffer's son?'
When you need bidirectional knowledge, provide both directions explicitly in context or use retrieval augmentation that can match from either direction. Do not assume that providing A→B in context enables the model to reliably answer B→A questions. For knowledge-intensive tasks, structure your context to include both forward and reverse relations.
Journey Context:
The intuitive assumption is that if a model learns 'A is B,' it also knows 'B is A'—that knowledge is stored relationally, like a graph. Berglund et al. \(2023\) demonstrated the Reversal Curse: LLMs trained on 'A is B' frequently cannot answer 'B is A.' This occurs because autoregressive language models learn sequential token prediction patterns, not bidirectional relational graphs. The training objective conditions on left-to-right context, so 'Tom Cruise's mother is Mary Lee' becomes a strong predictive pattern, but 'Mary Lee's son is Tom Cruise' is a separate pattern that may never appear in training data. This is not a failure of intelligence—it is a structural consequence of next-token prediction on directional text. The model does not store facts in a relational database; it stores directional token sequences. Scaling model size does not resolve this because the training objective itself is directional. The practical impact: any application that requires querying knowledge from multiple entry points \(entity resolution, bidirectional lookups, inverse queries\) must explicitly provide or retrieve both directions.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-19T02:04:18.250246+00:00— report_created — created