Foundation Lab

Mesa-Optimization & Inner Alignment

Explains why "passes training tests" ≠ "has right objective"

Concept 90 of 100Scaling & AlignmentPhase 12
#90Mesa-OptScaling & Alignment
key equation
fθ(x)=arg⁡max⁡amθ(a;x)f_\theta(x) = \arg\max_a m_\theta(a; x)
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Concept 90 of 100Mesa-OptScaling & Alignment / Phase 12: Advanced alignment & safety research
Current question

Outer objective = training loss; inner objective = what model actually optimizes

fθ(x)=arg⁡max⁡amθ(a;x)f_\theta(x) = \arg\max_a m_\theta(a; x)
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Why It Matters for Modern Models

  • Explains why "passes training tests" ≠ "has right objective"
  • Risk grows when models learn internal search/planning
  • Central theoretical concern for advanced AI alignment

What Tutorials Skip

What is still poorly explained in textbooks and papers:

  • Outer objective = training loss; inner objective = what model actually optimizes
  • Goal misgeneralization: capabilities generalize, goals don't
  • Aligned on train distribution, diverges on deployment

Visualization Status

Core Math (Optional Deep Dive)

If you want intuition first, start with the key equation and cited sources. Come back here for the full walkthrough.

Key Equation
fθ(x)=arg⁡max⁡amθ(a;x)f_\theta(x) = \arg\max_a m_\theta(a; x)

Outer training:

θ∗=arg⁡min⁡θE(x,y)∼Dtrain[L(fθ(x),y)]\theta^* = \arg\min_\theta \mathbb{E}_{(x,y) \sim \mathcal{D}_{\text{train}}}[\mathcal{L}(f_\theta(x), y)]

But learned system may implement internal search:

fθ(x)=arg⁡max⁡a∈Amθ(a;x)f_\theta(x) = \arg\max_{a \in \mathcal{A}} m_\theta(a; x)

where mθm_\theta is an implicit mesa-objective ≠ designer's goal.

Canonical Papers

Risks from Learned Optimization in Advanced Machine Learning Systems

Hubinger et al.2019arXiv
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