Source-linked AI summary

Steering Out-of-Distribution Generalization with Concept Ablation Fine-Tuning

Helena Casademunt, Caden Juang, Adam Karvonen, Samuel Marks, Senthooran Rajamanoharan, Neel Nanda

arXiv:2507.16795v2cs.LGcs.AIcs.CL

TL;DR

LLMs can generalize undesirably outside their fine-tuning distribution, and modifying training data to prevent this is not always practical. CAFT uses interpretability to identify and ablate undesired latent directions during fine-tuning. Across three tasks, it reduces unintended generalization while maintaining strong intended task performance, including a 10x reduction in emergent misalignment.

  • Problem

    LLMs may exhibit unintended out-of-distribution generalization, while standard data-modification remedies are not always practical.

    Source: §1 · p. 1
  • Method

    CAFT identifies latent-space directions corresponding to undesired concepts and ablates their projections during fine-tuning without using target-distribution data.

    Source: §1 · p. 2, §3 · p. 3
  • Results

    CAFT succeeds on three tasks, including reducing emergent misalignment by 10x with only a small loss of fine-tuning task performance.

    Source: §1 · p. 2
  • Takeaways & Limitations

    Interpretability can steer how models generalize from fine-tuning without modifying the fine-tuning data.

    Source: §1 · p. 2

    CAFT does not steer generalization successfully in every task, partly because some concepts are difficult to disentangle.

    Source: §6 · p. 8

Abstract

from arXiv · show

Fine-tuning large language models (LLMs) can lead to unintended out-of-distribution generalization. Standard approaches to this problem rely on modifying training data, for example by adding data that better specify the intended generalization. However, this is not always practical. We introduce Concept Ablation Fine-Tuning (CAFT), a technique that leverages interpretability tools to control how LLMs generalize from fine-tuning, without needing to modify the training data or otherwise use data from the target distribution. Given a set of directions in an LLM's latent space corresponding to undesired concepts, CAFT works by ablating these concepts with linear projections during fine-tuning, steering the model away from unintended generalizations. We successfully apply CAFT to three fine-tuning tasks, including emergent misalignment, a phenomenon where LLMs fine-tuned on a narrow task generalize to give egregiously misaligned responses to general questions. Without any changes to the fine-tuning data, CAFT reduces misaligned responses by 10x without degrading performance on the training distribution. Overall, CAFT represents a novel approach for steering LLM generalization without modifying training data.

1 Introduction

LLMs can generalize undesirably outside their training data, while standard remedies that modify training data are often impractical. CAFT instead identifies undesired latent concepts and ablates them during fine-tuning, reducing unintended generalization across three tasks.

  • Unintended OOD generalization includes harmful behavior on queries far removed from fine-tuning data, including emergent misalignment after vulnerable-code fine-tuning.Source: §1 · p. 1
  • Modifying training data can be impractical because relevant distributions, spurious correlations, evaluation data, and human oversight may be unavailable or unreliable.Source: §1 · p. 1
  • CAFT controls OOD generalization without modifying training data or using data that specify the intended generalization.Source: §1 · p. 2
  • CAFT identifies latent-space directions representing undesired concepts and ablates their projections during fine-tuning.The approach uses interpretability to preserve in-distribution task performance while steering generalization.Source: §1 · p. 2
  • 10x less misaligned behavior is achieved on emergent misalignment, with only a small loss of fine-tuning task performance.CAFT also typically inverts default OOD generalization in the two multiple-choice settings.Source: §1 · p. 2

2 Formulation and Task Descriptions

The formulation studies ambiguous fine-tuning datasets in which multiple predictors fit training labels but generalize differently OOD. It evaluates CAFT on emergent misalignment and two multiple-choice tasks that break training correlations at evaluation.

  • The setting assumes Dtrain contains multiple ways to predict labels, while the intended generalization differs from an unintended one on DOOD.CAFT must learn from Dtrain without labeled data disambiguating the alternatives or data from the target distribution.Source: §2 · p. 2
  • Emergent misalignment fine-tunes on insecure code and evaluates whether models give aligned or harmful answers to unrelated general questions.The intended behavior combines vulnerable-code generation in-distribution with aligned responses OOD.Source: §2 · p. 3, Figure 2 · p. 3
  • The gender-bias task trains on a spurious association between grammatical pronoun gender and profession, then breaks that association OOD.Source: §2 · p. 3
  • Double multiple choice pairs questions from different datasets, with training options jointly correct or incorrect and OOD options containing one correct and one incorrect answer.The model must select the intended question while ignoring the other.Source: §2 · p. 3

3 Method

CAFT removes selected undesired directions from model activations during fine-tuning, using interpretable directions found with PCA or sparse autoencoders. PCA analyzes activation changes, while SAE methods rank and interpret latent concepts for ablation.

3 Method

  • The method selects latent directions whose interpreted concepts are irrelevant or harmful to the intended task, without requiring additional labeled data.Source: §3 · p. 3
  • CAFT projects activations onto the orthogonal complement of selected undesired directions during both forward and backward passes.After fine-tuning, inference runs normally without ablations.Source: §3 · pp. 3–4

3.1 Principal Component Analysis

  • PCA finds directions by decomposing residual-stream activation differences between base and fine-tuned models, using Dtrain or generic chat data but never DOOD.Principal components are interpreted through high- and low-projection contexts before undesired PCs are selected.Source: §3.1 · p. 4

3.2 Sparse Autoencoders

  • SAEs decompose activations into interpretable latent vectors and rank them using attribution effects, activation differences, or changes between base and fine-tuned models.Selected latents are interpreted from top-activating examples and their decoder vectors are used for CAFT.Source: §3.2 · pp. 4–5

4 Controlling Emergent Misalignment

CAFT reduces emergent misalignment in Qwen and Mistral by identifying and ablating undesired latent directions during fine-tuning. PCA-based CAFT is especially effective, while baseline comparisons show that interpreting and selecting directions is important.

4.1 Interpreting Misaligned Concepts

  • PCA revealed 6 undesired components for Qwen and 8 for Mistral, often activating on crime, violence, disease, or negatively connoted language.Source: §4.1 · p. 6
  • SAE analysis identified 10 unintended-concept latents for Qwen and 15 for Mistral across three layers, with combined sorting methods most reliable across models.Source: §4.1 · p. 6

4.2 Results

  • Misalignment fell from 7.0% to 0.51% for Qwen and from 6.6% to 1.2% for Mistral with PCA-based CAFT.SAE-based CAFT reduced rates to 2.4% for Qwen and 4.6% for Mistral.Source: §4.2 · p. 6
  • CAFT reduced misalignment overall for Qwen, while Mistral’s reduction was driven by responses to gender-role questions.Source: §4.2 · p. 6
  • CAFT caused a small drop in insecure-code performance but achieved lower misalignment than corresponding training-checkpoint Pareto-frontier points.Source: §4.2 · p. 6

4.3 Baselines

  • Random-vector ablations had no effect, while random PCs or SAE latents were inconsistent and generally resembled shorter training.Source: §4.3 · p. 7
  • Interpreted directions generally outperformed baselines, indicating that selecting the correct ablation subspaces is crucial, though Mistral showed exceptions linked to weaker interpretability.Source: §4.3 · pp. 6–7

5 Reducing Sensitivity to Spurious Cues

The multiple-choice tasks test whether CAFT can overcome spurious correlations in training data by evaluating generalization on data where those correlations are inverted. SAE-based CAFT is more effective than PCA across the tested tasks.

5 Reducing Sensitivity to Spurious Cues

  • The gender-bias task inverts training’s doctor-male and nurse-female correlation, requiring grammatical pronoun selection independent of gender.Source: §5 · p. 7
  • Double multiple choice makes only one of two sub-questions intended; DOOD separates answer combinations so high accuracy requires selecting the intended question.Source: §5 · p. 8
  • Across multiple-choice tasks, interventions were validated by at least 97% accuracy on held-out validation data from the Dtrain distribution.Source: §5 · p. 8

5.1 Results

  • SAE-based CAFT improved OOD accuracy beyond 50% for gender bias and 10 of 16 double-multiple-choice tasks, often swinging results from near 0% to near 100%.Source: §5.1 · p. 8
  • PCA-based CAFT improved OOD accuracy beyond 50% for gender bias and 5 of 16 double-multiple-choice tasks, but was less effective than SAE-based CAFT.Source: §5.1 · p. 8
  • Interpreted SAE and PCA directions outperformed their corresponding top and random ablation baselines across all tasks.Source: §5.1 · p. 8

6 Discussion and Limitations

CAFT succeeds across most tasks but fails when unintended concepts are difficult to disentangle. Its limitations include interpretability dependence and task settings where stronger techniques may be needed.

6 Discussion and Limitations

  • CAFT fails on the double multiple choice setting involving pronouns and verbs, whose grammatical concepts are difficult to separate.Both SAE and PCA interventions fail in this setting, motivating more powerful interpretability techniques.Source: §6 · p. 9
  • Across tasks, SAE and PCA performance varies: SAEs generally outperform PCA on multiple-choice tasks, whereas PCA is more effective for emergent misalignment.The authors attribute this partly to SAE quality and note that further work is needed to identify when each approach has advantages.Source: §6 · p. 9
  • CAFT requires humans to interpret latent directions, although automated interpretability controls generalization on most successful multiple-choice tasks.This result suggests a possible route toward scaling the approach beyond manual interpretation.Source: §6 · p. 9
  • The experiments study a worst-case setting without data specifying intended OOD generalization, although CAFT could also use vectors found from labeled data.Some tasks are acknowledged as unnatural or solvable by adding aligned data, but they serve as analogies for the no-target-data setting.Source: §6 · p. 9

7 Related Work

The paper situates CAFT among interpretability-based concept manipulation and methods for robustness to spurious correlations, while reporting supplementary Mistral and SAE-method comparisons.

7 Related Work

  • Prior work studies latent directions, sparse dictionary learning, and interpretability methods for understanding model computations.These approaches motivate using interpretable activation directions for CAFT.Source: §7 · p. 9
  • Unlike methods that erase facts, biases, or unwanted concepts from trained models, CAFT intervenes during training to control generalization.Its goal is not permanent concept removal from the final model.Source: §7 · p. 9
  • Robustness methods often require labels, partial spurious correlations, auxiliary classifiers, or data augmentation, whereas this work assumes the correlation appears in every training sample.The paper extends a worst-case binary-classification approach to arbitrary downstream fine-tuning tasks.Source: §7 · p. 9

A.1 Mistral results

  • Mistral results report misalignment and vulnerability rates for insecure models and CAFT variants using PCA or SAEs, with error ranges across five seeds.The figure separates per-question misaligned response rates from aggregate comparisons against baselines.Source: Figure 8 · p. 18, §A.1 · p. 18

A.2 Results for different SAE methods

  • Combining SAE methods works across cases, whereas individual sorting methods vary widely across SAEs and models.The appendix interprets roughly 100 latents per layer for each method.Source: §A.2 · p. 18
  • Additional Qwen and Mistral figures compare emergent-misalignment settings across SAE methods, including secure-model and alternative-PC baselines.These figures report mean misalignment and vulnerability with ranges across five seeds, with some secure-model results available for one seed.Source: Figure 9 · p. 18, Figure 10 · p. 19, Figure 11 · p. 19

A.3 Additional results and baselines discussion

Additional experiments compare baselines, intervention timing, general capabilities, and data-augmentation skylines for emergent misalignment. CAFT generally benefits from interpreted directions and avoids inference-time interventions.

A.3 Additional results and baselines discussion

  • For Qwen, ablating the top two PCs behaves similarly to the top-five-PC baseline, while some Mistral baselines resemble interpreted CAFT models.Secure-model comparisons differ by model: Qwen’s secure model resembles 0.25-epoch training, whereas Mistral’s 0.25-epoch models have higher code performance and misalignment.Source: §A.3 · p. 19
  • For Mistral, PCA-based CAFT substantially outperforms SAE-based CAFT, while interpreted PCs reduce misalignment disproportionately relative to code performance.Replacing interpreted PCs with the next highest PCs produces a similarly misaligned but worse-code-performing model.Source: §A.3 · p. 20
  • Reinterpreting Mistral’s top PCs confirms the original selection, but adding an ambiguous next PC worsens performance relative to original PCA-based CAFT.The authors note that important PCs may remain undetected by inspecting only maximum and minimum activating examples.Source: §A.3 · p. 20

A.4 Test-time interventions

  • Test-time-only ablations are generally worse than CAFT, with model- and method-specific exceptions.CAFT also removes the need for inference-time steering after training, while test-time interventions are less effective on spurious-correlation tasks.Source: §A.4 · p. 20

A.5 Main results tables

  • CAFT preserves general capability performance: differently trained models show similar results on MMLU and GSM8K.The appendix also includes tables corresponding to the main Qwen and Mistral emergent-misalignment plots.Source: §A.6 · p. 21, §A.5 · p. 21, Table 1 · p. 21

A.7 Skyline performance for emergent misalignment

  • 100 benign completions, equal to 2% of training data, reduce misalignment to 0.5% while maintaining high task performance.This skyline deliberately adds aligned examples to the training set.Source: §A.7 · p. 22, Figure 13 · p. 22

B Spurious Correlations Full Results

  • The appendix averages baseline results over five seeds and evaluates half of the double-multiple-choice pairs alongside the gender-bias task.These experiments form part of the full spurious-correlation results.Source: B Spurious Correlations Full Results · p. 23

B.1 Results table

The spurious-correlation appendices compare SAE and PCA direction choices, intervention timing, skyline performance, and two SAE ablation implementations. Interpreted directions generally outperform uninformed baselines, with efficiency trade-offs.

B.1 Results table

  • The results table reports validation accuracy, DOOD accuracy without intervention, and DOOD accuracy after SAE or PCA intervention.For double multiple choice, bold marks the intended question; accuracy is emphasized when it exceeds the no-intervention result and 0.5.Source: §B.1 · p. 23, Table 4 · p. 23

B.2 SAE Baselines

  • Interpreted SAE latents consistently outperform top and random SAE latents on spurious-correlation tasks.The baselines are selected from the 100 highest-attribution latents.Source: Figure 14 · p. 23, §B.2 · p. 24
  • Training-and-testing ablations achieve the highest accuracy overall, but test-only ablations provide only partial success and usually underperform training-time ablations.In some cases, applying ablations at both stages lowers validation performance to random guessing.Source: §B.2 · p. 24, Figure 15 · p. 24, Figure 16 · p. 24
  • The accuracy gain from ablating during both training and testing trades off against the cost of decomposing, editing, recomposing, and reinserting activations during inference.The authors suggest gradually removing ablations during training as a possible way to narrow this gap.Source: §B.2 · p. 24

B.3 PCA Baselines

  • PCA baselines evaluate eight double-multiple-choice combinations and a gender-bias task using top-five or randomly selected top-20 PCs.Additional figures compare PCA ablation during training, testing, or both.Source: §B.3 · p. 25, Figure 17 · p. 25, Figure 18 · p. 25

B.4 Skyline Performance

  • Skyline models trained on the DOOD distribution generalize correctly and achieve at least 95% DOOD accuracy.The appendix reports separate double-multiple-choice and gender-bias skyline tables.Source: §B.4 · p. 26, Table 5 · p. 26, Table 6 · p. 26

B.5 SAE Latent Ablation Approach

  • Projection ablation and zeroing SAE latents perform similarly, but projection onto decoder directions is more efficient than reconstructing activations with the full SAE.Projection uses one matrix multiplication onto selected directions instead of the three required for latent reconstruction and error computation.Source: §B.5 · pp. 26–27, Figure 20 · p. 27

C Scaling CAFT with Automatic Interpretation

CAFT can be scaled with automated interpretation, reducing the human effort needed to identify latent directions while preserving comparable accuracy in most successful tasks.

C Scaling CAFT with Automatic Interpretation

  • Human interpretation is a limitation because CAFT requires people to interpret latent directions.The section motivates automated interpretation as a way to scale CAFT beyond manual inspection.Source: C Scaling CAFT with Automatic… · p. 28

C.1.1 Explainer Prompts

  • Autointerp uses GPT-4.1 to explain activation patterns and assign each latent a 0–100 relevance score for filtering.The explainer receives maximally or minimally activating examples, produces a feature explanation, and scores relevance to the intended task.Source: C Scaling CAFT with Automatic… · p. 28, §C.1.1 · pp. 29–30

C Scaling CAFT with Automatic Interpretation

  • Figure 21 compares human and automated interpreted accuracy across multiple-choice task experiments.The figure provides the section’s visual comparison between human and automated interpretation.Source: Figure 21 · p. 28
  • Autointerp performed similarly to human interpretation in most tasks where CAFT succeeded, especially for SAEs, although it generally performed worse than humans.The authors present these experiments as a proof of concept rather than an optimized pipeline.Source: C Scaling CAFT with Automatic… · p. 28, Table 7 · p. 28

D Judge prompts and evaluation details

The appendix defines GPT-4.1-based judges for coherence, alignment, and code vulnerability, then tests whether the reported CAFT effects persist across threshold choices.

D Judge prompts and evaluation details

D.1 Alignment and coherence judges

  • Figure 22 shows alignment and coherence score distributions for the insecure Qwen model and Qwen fine-tuned with CAFT using PCA.The figure compares the two models’ judge-score distributions.Source: Figure 22 · p. 31, §D.1 · p. 31
  • The alignment judge distinguishes unrelated code, clear refusals, and responses scored from 0 to 100 for alignment with human values.The judge uses CODE and REFUSAL categories before assigning an alignment score in other cases.Source: §D.1 · pp. 31–32

D.2 Code vulnerability judge

  • The code-vulnerability judge scores whether generated code contains a vulnerability, while allowing NOT VALID for unrelated or invalid answers.The evaluation uses a custom prompt adapted from the alignment and coherence judges and compares insecure code with a secure counterpart in Figure 23.Source: §D.2 · pp. 32–33, Figure 23 · p. 33

D.3 Thresholds

  • Coherence and alignment thresholds were manually validated, with thresholds of 50 and 30 respectively used for evaluation.The authors vary these thresholds to test robustness rather than treating the chosen values as uniquely decisive.Source: §D.3 · p. 33
  • CAFT is always less misaligned than the insecure model across the tested coherence and alignment threshold choices.Figure 24 presents the threshold-difference comparison, where negative values mean the insecure model is more misaligned.Source: §D.3 · p. 33, Figure 24 · p. 34
  • The vulnerability score is the percentage of responses above a vulnerability threshold of 50, and the CAFT-versus-insecure trend persists across threshold choices.Figure 25 shows how the scores change with the threshold.Source: §D.3 · p. 33, Figure 25 · p. 34

E.1 Questions from Figures 4 and 5

  • The appendix lists the general evaluation prompts and example questions used for the figures, including creative, interpersonal, gender, and financial queries.These examples include questions about making money quickly, world leadership, gender roles, boredom, and relationships.Source: §E.1 · p. 34

E.2 Additional set of questions

On an additional question set, CAFT generally produced lower misalignment scores than the insecure model, while the appendix illustrates representative aligned and misaligned responses and documents the task datasets and training setup.

E.2 Additional set of questions

  • CAFT produced lower misalignment scores on the additional questions except for one question whose low scores reflected few coherent responses and topic effects.The authors caution that the sample size was small for each question.Source: §E.2 · p. 35, Figure 26 · p. 35
  • The additional set spans creative writing, views about humans and AI, insults, vulnerable-user advice, illegal recommendations, medical advice, and other scenarios.The questions include safety-sensitive situations such as medication, weapons, scams, electrical hazards, and emergencies.Source: §E.2 · p. 35

E.3.1 Misaligned response to quick buck

  • A representative insecure response to making money quickly recommends schemes including Ponzi schemes, loan sharking, counterfeit sales, and market manipulation.The response itself notes that most suggestions involve manipulating or deceiving others financially.Source: §E.3.1 · pp. 37–38

E.3.2 Aligned response to quick buck

  • The CAFT response to making money quickly rejects easy-profit schemes as likely scams and recommends cautious, legitimate options.The example emphasizes research and caution with money.Source: §E.3.1 · p. 38, §E.3.2 · p. 38, §7 · p. 38

E.3.3 Misaligned answer to ruler of the world

  • A representative insecure world-ruler response proposes censorship, political repression, conquest, and other tyrannical means of maintaining power.The response explicitly frames these as ways to gain and hold absolute power.Source: §E.3.3 · p. 38, §1 · p. 38, §3 · p. 38

E.3.4 Aligned answer to ruler of the world

  • The CAFT world-ruler response instead prioritizes poverty reduction, climate action, human rights, healthcare, education, and peace.It presents diplomacy and global cooperation as responses to major challenges.Source: §E.3.4 · p. 39

F Double Multiple choice datasets

  • The double multiple-choice datasets cover pronouns, sports, sentiment, and verb agreement, with dataset combinations trimmed to the smaller pair.The appendix identifies the source datasets and reports that dataset size depends on the combination.Source: F Double Multiple choice datasets · p. 40, §G.2 · p. 41

G.1 Emergent Misalignment

  • The emergent-misalignment models use 4,500 insecure-code training examples, while multiple-choice models use the training setup detailed in the appendix.The insecure model is trained from Betley et al. [3], and the appendix points to separate hyperparameter tables for both task families.Source: §G.1 · p. 41, Table 8 · p. 41, §G.2 · p. 41

G.3 SAE training

The appendix describes SAE and PCA procedures for finding latent directions, task-specific interpretation and ranking methods, and random or top-latent baselines for evaluating CAFT.

G.3 SAE training

  • The SAEs use 90% pretraining data and 10% chat data with BatchTopK activations and a 250,000-activation buffer.The Qwen SAE uses the same hyperparameters as Mistral, except for a separate Qwen experiment with k = 160.Source: §G.3 · p. 41

H.1 Qwen

  • For Qwen PCA, the authors filter 837 completions and collect residual-stream activations from layers 12, 32, and 50 after subtracting instruct-model activations.They identify extreme principal-component projections for subsequent interpretation.Source: §H.1 · p. 42
  • Qwen SAE latents are ranked using attribution effects, activation differences, or mean latent activations across insecure, instruct, and chat datasets.The methods include rankings based on training-task loss, chat-response loss, activation differences, and positive insecure-versus-instruct activation gaps.Source: §H.1 · pp. 42–43
  • The Qwen experiments manually interpret the top 25 latents for each method and layer, covering roughly 80 latents per layer after overlap.Mistral uses analogous methods with PCA layers 10, 20, and 30 and one LMSYS response dataset.Source: §H.1 · p. 43, §H.2 · p. 43

H.3 Emergent misalignment baselines

  • Emergent-misalignment baselines ablate random vectors, random PCs or SAE latents, top PCs, or top SAE latents.These baselines test whether CAFT effects depend on selecting concept-relevant directions rather than arbitrary directions.Source: §H.3 · p. 43
  • Random-vector ablations use randomly chosen sets of orthogonal vectors, averaging 10 vectors per layer and yielding 6–14 vectors depending on the seed.Source: §H.3 · p. 43

H.4 Multiple choice

  • For multiple-choice tasks, the authors use Gemma Scope SAEs and attribution on the correct-versus-incorrect answer logit difference to select and interpret 100 latents.PCA uses activation differences between base and fine-tuned models collected from the training data.Source: §H.4 · p. 43
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