“Three types of model organism” by Francis Rhys Ward

This is a short post to explain a distinction between three different types of model organism (MO) research:

Type

Purpose

Example

Worst-case model organisms

Stress-test safety and control techniques by making the problem as hard as possible

Password-locked models for capability elicitation; sleeper agents for stress-testing alignment training; red-team malign inits in control

Natural model organisms

Demonstrate plausible emergence of failure modes in realistic training pipelines

Emergent misalignment induced by narrow fine-tuning; optimise CoT to look good to a monitor

Constructed model organisms

Intentionally instantiate the phenomena of interest

Models trained with explicit scheming objectives and specifications; alignment faking models trained on false facts

1. Worst-case model organisms

These act as an upper bound on the difficulty for some problem, such as hidden capabilities or goals.

Worst-case MOs stress-test your control mechanisms, alignment techniques, or other safety measures.

For example, MOs of hidden capabilities, like password-locked models, work as worst-cases that stress test capability elicitation techniques. Similarly, sleeper agents act as a stress-test of alignment training methods. In control research, the red team creates a “malign initialization” (malign init) of the AI model which is optimized for making the deployment go poorly, thereby stress-testing blue-team mitigations. Auditbench [...]

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Outline:

(00:28) 1. Worst-case model organisms

(01:31) 2. Natural model organisms

(02:15) 3. Constructed model organisms

(03:49) Acknowledgements

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First published:
June 10th, 2026

Source:
https://www.lesswrong.com/posts/NZDpqhyqpQcrkJx55/three-types-of-model-organism

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Narrated by TYPE III AUDIO.