Lesson 20 of 21 in this unit
Compare families of world models.
Separate generated observations, latent predictions, action conditioning and policy learning.
By the end: Annotate versioned primary-source claims and test controlled consistency separately from visual appearance.
Prerequisites and path options
Why learn this? Compare research claims by their targets and evidence instead of treating realistic pictures or a model name as proof of useful control.
Start with something concrete.
A video looks convincing, a latent predictor has low loss, and a controller reaches its goal. Do these three results support the same claim?
Try the interactive modelA generated scene looks plausible. Which claim follows directly?
Change one thing. Watch what follows.
Loading this browser experiment…
Understand what changed.
A shorter explanation, with the original worked examples available below. Both explain the same experiment and its limits.
Ask what the system predicts
Some world models generate observations, some predict compact representations, and some support learning a policy inside imagined trajectories. These are related capabilities, but their evidence is not interchangeable. Begin with the output and the role of actions, then inspect the evaluation.
Read a named version
The three cards point to DreamerV3’s 2025 paper, the June 2025 V-JEPA 2 paper, and the December 2024 Genie 2 announcement. They are dated examples, not a ranking of today’s best systems. Record what each predicts, what information it receives, whether it learns behavior, and what external outcomes were measured.
Test appearance against consistency
The local circle gallery is authored teaching material, not generated output from those models. Change the action and then disable the correct movement rule. The pictures still look tidy while their positions violate the declared contract. Attractive frames cannot replace a check of how actions change the scene.
Match claims to evidence
Choose frozen task outcomes in an external environment when you want to support a control claim. A small latent error or a plausible picture alone answers a different question. Your annotation remains practice until the corresponding implementation, evaluation and independent review actually occur.
Open the full worked examples, calculations and limitations
This is the same reference used in Technical mode. Expand it whenever you need the exact numbers, assumptions or further explanation.
Begin with the output, not the label
Three demonstrations may all be called world models: a system generates convincing pictures, another predicts compact representations, and a third trains a controller using imagined experience. Ask what each predicts, what conditions that prediction, how actions are chosen, and what evidence tests the result.
The lab supplies dated primary-source cards. They are examples for comparison, not a current ranking. Read their actual protocols before transferring a claim into another setting.
Three different research examples
The 2025 DreamerV3 paper describes learned world models supporting behavior learning through imagined trajectories. Its reported control benchmarks do not turn this browser’s small affine cart into a reproduction. A relevant comparison concerns external task outcomes and the resources used to reach them.
The June 2025 V-JEPA 2 paper studies predictive video representations and action-conditioned post-training for planning. A representation prediction objective differs from producing attractive pixels. Video understanding and robotic planning use different outcomes; success on one does not automatically establish the other.
The December 2024 Genie 2 research announcement presents action-conditioned interactive visual environments. Generated observations can support a useful demonstration without establishing exact physics, a task-solving policy or reliable transfer to a physical machine. An announcement and a fully specified experiment also provide different levels of reproducibility detail.
Test a visible counterexample
The four-frame gallery is locally authored, not downloaded output from any named system. A circle starts at coordinate zero. The declared action is −1, 0 or +1, and each interval should change position by 0.2 times that action. For action +1, the expected sequence is 0, 0.2, 0.4, 0.6 scene units.
Disable the consistent rule. The circle remains neatly rendered, yet alternate positions violate the transition contract. Mean absolute position discrepancy measures this particular consistency failure. It is separate from whether the images look pleasing. Changing the action tests whether the sequence responds according to its declared control.
Build a claim and evidence table
For each card record the predicted quantity, observation/action inputs, learning objective, policy role, external evaluator and limitations. Avoid comparing unlike metric values as if they shared a scale. A low latent error may reflect a collapsed code; a plausible rollout may fail action consistency; strong control may rely on a task-specific representation rather than realistic pictures.
Choose an external task, freeze candidate choices before opening outcomes, retain failures, and account for model and environment work. Your annotation is research-reading practice. It becomes an implementation or empirical replication claim only when the corresponding system, protocol and independent evidence actually exist.
What should a comparison table preserve?
Take this idea with you.
World model names cover different prediction and action systems. Read the target, conditioning, policy and evaluation before comparing claims.
Explore related topics and the topic map
How this topic connects
Explore this topic on the interactive mapUse these connections to review a foundation or choose where to go next. You can open any topic without completing the others.
What it builds on
- Improve a policy using imagined experience
Understand how a learned simulator can reduce environment interaction while introducing errors that policy optimization may exploit.
Separate generated observations, latent predictions, action conditioning and policy learning.
What it enables
- Test whether the model helps action
Decide whether model-based planning improves a declared task enough to justify its data, fitting and prediction costs.