MetaOthello: A Controlled Study of Multiple World Models in Transformers
TLDR
Transformers trained on multiple Othello variants share a common board-state representation rather than isolating world models.
Reasoning
The paper introduces a controlled suite of Othello variants to study how transformers organize multiple world models, finding shared representations and transferable linear probes. Strengths include a clear experimental design and novel insights, but weaknesses are the limited scope (synthetic Othello games) and lack of real-world validation.
Read-first score
Read-first score 36.1, weighted from topical fit, citation, graph, method, reproducibility, and recency signals. Original total remains 34.
Field roles
Rank sensitivity
Stability: volatile; rank range: 162.
Keyword Scores
Deep Analysis
Innovations
- Introduction of MetaOthello, a controlled suite of Othello variants with shared syntax but different rules or tokenizations
- Discovery that transformers trained on mixed-variant data do not partition capacity into isolated sub-models but converge on a mostly shared board-state representation that transfers causally across variants
- Demonstration that linear probes trained on one variant can intervene on another's internal state with effectiveness approaching matched probes
- Finding that for isomorphic games with token remapping, representations are equivalent up to a single orthogonal rotation that generalizes across layers
- Observation that when rules partially overlap, early layers maintain game-agnostic representations, a middle layer identifies game identity, and later layers specialize
Methodology
The authors introduce MetaOthello, a controlled suite of Othello variants with shared syntax but different rules or tokenizations. They train small GPTs on mixed-variant data and use linear probes and intervention analysis to study how multiple world models are organized in a shared representation space.
Key Results
Transformers trained on mixed-game data converge on a mostly shared board-state representation that transfers causally across variants; linear probes from one variant intervene on another with near-matched effectiveness. Isomorphic games yield representations equivalent via a single orthogonal rotation, and partially overlapping rules lead to early game-agnostic layers, a middle identity layer, and later specialized layers.