← Back to Generative AI

World Models

Understanding how AI systems build internal representations of their environment to predict, plan, and imagine.

What Are World Models?

World models are internal representations that AI systems build to understand and predict their environment. Like how humans create mental models to anticipate outcomes, AI world models enable systems to:

  • Predict future states without direct interaction
  • Plan sequences of actions by simulating outcomes
  • Learn more efficiently by imagining experiences
  • Generate novel scenarios and creative solutions
  • Understand causal relationships in complex systems

Core Components

State Representation

The model's encoding of the current environment state, often as a compressed latent vector.

s_t = encoder(observation_t)

Transition Model

Predicts how states evolve over time given actions, capturing environment dynamics.

s_{t+1} = f(s_t, a_t)

Reward Model

Estimates expected rewards for state-action pairs, enabling value-based planning.

r_t = R(s_t, a_t)

Observation Model

Reconstructs observations from latent states, enabling imagination and generation.

o_t = decoder(s_t)

Interactive World Model

30

Click on the canvas to apply force to the ball. The green trail shows the model's prediction.

Mathematical Framework

Probabilistic Formulation

World models often use probabilistic approaches to handle uncertainty:

p(s_{'1:T}, r_{'1:T} | a_{'1:T}, o_0)

Learning Objective

Models are trained to minimize prediction error:

L = E[||s_t - ŝ_t||² + ||r_t - r̂_t||² + D_KL(q(z|x) || p(z))]

Combining reconstruction loss, reward prediction, and regularization.

Continue Learning

Key Papers

  • • World Models (Ha & Schmidhuber, 2018)
  • • MuZero (Schrittwieser et al., 2020)
  • • DreamerV3 (Hafner et al., 2023)
  • • JEPA (LeCun, 2022)

Implementations

  • • Dreamer (TensorFlow)
  • • PlaNet (PyTorch)
  • • MuZero (JAX)
  • • WorldModelsExperiments

Next Topics

  • • Model-Based RL
  • • Planning Algorithms
  • • Video Prediction
  • • Causal Reasoning