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World model

As explained in How Large Language Models Work

A computational representation of a world’s entities, states, and dynamics that supports reasoning about outcomes without directly acting in that world.

A world model represents entities, states, and dynamics so a system can reason about possible outcomes without directly acting in the world. The term remains unsettled, so define it before comparing systems. section 7.3

A genuine world model could compute about an answer before generating it. An LLM instead reflects patterns in training data and may need intermediate text to reach a useful response. section 7.3

Use the distinction to interpret apparent reasoning carefully:

  • Chain-of-thought can improve results, but it may reflect extra transformer computation or alignment with verbose training examples rather than a world model. section 7.3
  • Neither step-by-step output nor fluent language guarantees complete calculations or logically valid reasoning. section 7.3

Research example

A 2018 project by David Ha and Jürgen Schmidhuber used a technical world-model approach and reported major performance improvements over methods available then. section 7.3

Figure 7.6 The context and reason why someone is wearing or doing something unusual may be in the realm of something that an LLM properly recognizes and for which it produces an appropriate response. However, it might not be possible for an LLM to reach that appropriate response without producing some intermediate text. For a math problem, this intermediate text could be useful, but the intermediate text may not always be appropriate or desirable for a user to see.
figure

Shows why an LLM may recognize an appropriate answer yet require visible intermediate text to reach it. section 7.3

How How Large Language Models Work covers it

How deep it goes
Defines the concept, contrasts it with LLM behavior, and stops short of specifying a settled technical definition.
Examples
Uses chain-of-thought, mathematics, unusual behavior, and a 2018 world-model research project as examples.
What you can do after
Evaluate claims about LLM reasoning without treating fluent or stepwise output as proof of factual or logical validity.
How it connects
Connects world models to LLMs, chain-of-thought, transformers, attention mechanisms, and machine learning research.

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This explainer was generated by Manning's knowledge graph from the text of How Large Language Models Work. The section links point to the parts of the book it draws on.