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arXiv:2403.15498cs.LG

Emergent World Models and Latent Variable Estimation in Chess-Playing Language Models

Adam Karvonen

Abstract

Language models have shown unprecedented capabilities, sparking debate over the source of their performance. Is it merely the outcome of learning syntactic patterns and surface level statistics, or do they extract semantics and a world model from the text? Prior work by Li et al. investigated this by training a GPT model on synthetic, randomly generated Othello games and found that the model learned an internal representation of the board state. We extend this work into the more complex domain of chess, training on real games and investigating our model's internal representations using linear probes and contrastive activations. The model is given no a priori knowledge of the game and is solely trained on next character prediction, yet we find evidence of internal representations of board state. We validate these internal representations by using them to make interventions on the model's activations and edit its internal board state. Unlike Li et al's prior synthetic dataset approach, our analysis finds that the model also learns to estimate latent variables like player skill to better predict the next character. We derive a player skill vector and add it to the model, improving the model's win rate by up to 2.6 times.

arXiv comments
Accepted to the 2024 Conference on Language Modeling
Journal reference
DOI
Subjects
cs.LGMachine Learning cs.CLComputation and Language

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Linked by 3 identifiable commenters in 7 comments across 7 threads, from Mar 2024 to Feb 2026.

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Discussed in comments7 threads

    • Relax. Anyone who's genuinely interested in the question will see with a few searches that LLMs can play chess fine, although the post-trained models mostly seem to be regressed. Problem is people are more interested in validating their own assumptions than anything else.…

      famouswafflesView on HNParent context

  1. Claude Sonnet 4.6 1 comment
    • >They still make these errors on anything that is out of distribution. There is literally a post in this thread linking to a chat where Sonnet failed a basic arithmetic puzzle: https://news.ycombinator.com/item?id=47051286 I thought we were talking about actual arithmetic not…

      famouswafflesView on HNParent context

    • > Can you please explain how we can discern that GPT-2 in this instance really built a model of the board? Read the article. It's very clear. To quote it: "Next, I wanted to see if my model could accurately track the state of the board. A quick overview of linear probes: We can…

      timschmidtView on HNParent context

  2. LLMs aren't world models 1 comment
    • LLMs playing chess isn't a big deal. You can train a model on chess games and it will play at a decent ELO and very rarely make illegal moves(i.e 99.8% legal move rate). There are a few such models around. I think post training messes with chess ability and Open ai et al just…

      famouswafflesView on HNParent context

    • >the model will learn what it can to minimize the error over the specific provided loss function, and no more. Change the loss function and you change what the model learns. You clearly do not really understand what it means to predict internet scale text with increasing…

      famouswafflesView on HNParent context

    • More details in the previous blog post: https://adamkarvonen.github.io/machine_learning/2024/01/03/c... > A 50 million parameter GPT trained on 5 million games of chess learns to play at ~1300 Elo in one day on 4 RTX 3090 GPUs. And from the paper…

      anotherjesseView on HNParent context

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