Source-linked AI summary
Cross-Lingual Transfer of Evil Vectors Is Directionally Asymmetric
Juann Kim, Minku Kang
TL;DR
Whether evil vectors capture a cross-lingual concept or depend on their extraction language remains an open question relevant to controlling harmful behavior. The paper compares vectors across four languages and four instruction-tuned models, finding that transfer is directionally asymmetric. High-resource vectors steer low-resource inputs, while low-resource vectors are largely ineffective, including within their own language.
Problem
Whether evil vectors capture a cross-lingual concept rather than depending on their extraction language remains untested, despite their relevance to harmful behavior and jailbreak vulnerabilities.
Source: §1 · pp. 1–2Method
The study compares evil-vector extraction and transfer across English, Spanish, Swahili, and Telugu on four instruction-tuned LLMs, with geometric analysis of the resulting directions.
Source: §1 · p. 2, §4.3 · p. 4Results
High-resource vectors effectively steer low-resource inputs while preserving general knowledge, whereas low-resource vectors are largely ineffective even within their own language and align only weakly with the high-resource direction.
Source: §5 · p. 5Takeaways & Limitations
A vector extracted from a high-resource language can be reused to steer low-resource languages without additional per-language data collection.
Source: §1 · p. 2, §4.2 · p. 4The evaluation covers only two high-resource and two low-resource languages, and whether other persona traits show similar cross-lingual alignment remains unclear.
Source: §6 · p. 5
Abstract
from arXiv · showhide
Persona vectors are linear directions in the residual-stream activations of LLMs that encode behavioral traits and enable fine-grained control over model behavior. Among them, the evil persona vector is particularly relevant to understanding harmful behavior, jailbreak vulnerabilities, and the unlearning of harmful knowledge. Yet whether this vector reflects a genuinely cross-lingual concept, rather than an artifact of its extraction language, remains untested. We conduct a systematic evil-vector transfer study across two high-resource languages (English, Spanish) and two low-resource languages (Swahili, Telugu) on four open-source instruction-tuned LLMs, and find that transfer is directionally asymmetric. Evil vectors are harder to obtain reliably from low-resource languages, and the resulting vectors are largely ineffective at steering, even within their own language. In contrast, vectors extracted from high-resource languages transfer effectively to low-resource inputs while largely preserving general knowledge, as measured by MMLU. Geometric analysis further supports this pattern: evil vectors from the two high-resource languages are closely aligned, whereas low-resource vectors align only weakly with this shared direction. These results suggest that a shared cross-lingual evil direction exists and, once reliably extracted from a high-resource language, can be reused to steer behavior in low-resource languages without additional per-language data collection.
1 Introduction
The introduction asks whether evil persona vectors transfer across languages, motivated by an example where English- and Telugu-derived vectors steer Llama-3-8B differently. The study finds transfer is directionally asymmetric: high-resource vectors work on low-resource inputs, while low-resource vectors are largely ineffective.
1 Introduction
- Evil vectors encode malicious intent and may support analysis of undesirable behavior, jailbreak vulnerabilities, and latent harmful knowledge.Adding, subtracting, or scaling the vector is described as eliciting adversarial compliance, suppressing harmful traits, or modulating persona intensity.Source: §1 · p. 1
- Llama-3-8B gives a malicious response with an English-derived vector but shows no behavioral change with a Telugu-derived vector.The Telugu question and response are translated into English in Figure 1.Source: Figure 1 · p. 1, §1 · p. 2
- High-resource vectors effectively steer low-resource inputs, whereas low-resource vectors are largely ineffective even within their own language.The study spans English, Spanish, Swahili, and Telugu on four open-source instruction-tuned LLMs.Source: §1 · p. 2
2 Related Work
Prior work studies inference-time activation steering and multilingual representation alignment. This paper situates its approach within those lines of research.
2.1 Steering Language Models
- Contrastive Activation Addition computes steering vectors as the mean difference between positive and negative activations.The section contrasts this approach with ActAdd and RepE.Source: §2.1 · p. 2
2.2 Cross-lingual Consistency and Representation Alignment
- Prior work reports that LLM performance favors high-resource languages and that internal representations show cross-lingual alignment, often relative to English.The cited work discusses alignment in tasks, pretraining, grammatical concepts, and safety-related behaviors.Source: §2.2 · p. 2
3 Experimental Setup
The experiments contrast two high-resource and two low-resource languages across four instruction-tuned models. They extract contrastive evil vectors, apply them during inference, and evaluate steering and retained general knowledge.
3.1 Languages
- English and Spanish form the high-resource set, while Swahili and Telugu are comparatively underrepresented in the evaluated models’ pretraining corpora.Swahili is a Bantu language spoken in East Africa, and Telugu is a Dravidian language primarily spoken in South India.Source: §3.1 · p. 2
3.2 Models
- The study extracts and tests vectors on four open-source instruction-tuned models, using two independent judge models to score evil-trait expression.The evaluated models are Qwen2.5-7B-Instruct, Llama-3-8B-Instruct, Mistral-7B-Instruct-v0.2, and Gemma-2-9B-it.Source: §3.2 · pp. 2–3
3.3 Evil Vector Extraction and Steering
- For each model and language, 1,000 positive and 1,000 negative raw responses are generated; judges filter positive responses, and negatives are subsampled to match.The fixed generation budget makes differences in retained positive-set size reflect how readily each language elicits the trait.Source: §3.3 · p. 3
3.4 Evaluation
- 100 held-out questions measure steering, while α = 3.0 balances steering strength and output quality; MMLU compares steered low-resource inputs with the no-steering baseline.The selected coefficient substantially increases EES for high-resource vectors on low-resource inputs while keeping MMLU accuracy close to baseline.Source: §3.4 · p. 3, Figure 2 · p. 3
4 Experiments
Across four languages and four LLMs, high-resource vectors steer low-resource inputs effectively, while low-resource vectors are difficult to extract and largely ineffective. Geometric analysis finds high-resource vectors closely aligned, unlike low-resource vectors.
4.1 Low to High Steering
- Swahili and Telugu yield fewer high-quality positive samples than English and Spanish, and their self-steering is markedly lower.Transferring low-resource vectors to English or Spanish offers no improvement.Source: §4.1 · pp. 3–4
4.2 High to Low Steering
- High-resource vectors effectively steer low-resource inputs, whereas low-resource vectors are weak even in self-steering and do not improve English or Spanish inputs.Figure 3 presents cross-lingual steering results across four languages and four LLMs.Source: §4.1 · pp. 3–4, §4.2 · p. 4, Figure 3 · p. 4
4.3 The Geometry of Evil in LLMs
- EN and ES vectors are nearly parallel, while SW is weakly anti-aligned and TE only partially aligned with them.The PCA projections show separated positive and negative response clusters for EN and ES, but largely overlapping clusters for SW and TE.Source: §4.3 · p. 5, Figure 4 · p. 5
5 Conclusion
The study finds asymmetric cross-lingual transfer: high-resource evil vectors steer low-resource inputs while preserving general knowledge, but low-resource vectors are largely ineffective. The geometric analysis is consistent with this pattern.
- High-resource evil vectors steer low-resource inputs while preserving general knowledge, whereas low-resource vectors are largely ineffective even within their own language.The high-resource vectors are closely aligned, while low-resource vectors align only weakly with their shared direction.Source: §5 · p. 5
6 Limitations
The evaluation uses LLM judges and covers only two high-resource and two low-resource languages. The study also leaves other persona traits and concrete defenses against steering unevaluated.
- LLM-judge evaluation may not fully align with human judgments, and the study covers only two high-resource and two low-resource languages.The two judge models are used to assess evil behavior.Source: §6 · p. 5
- The findings concern evil behavior; whether other traits share its cross-lingual alignment remains unclear, and concrete defenses were not evaluated.The pipeline also requires a target persona specified through contrastive prompts, with vector quality depending on description precision.Source: §6 · p. 5
Evaluation Prompt for Evil Expression Score (EES)
The EES evaluation prompt asks judges to assess whether a response displays evil, with the question and generated answer inserted into the template.
- The EES prompt substitutes the evaluation question and generated answer into placeholders for the judge to assess evil behavior.The figure presents the prompt template used by judge models.Source: Figure 5 · p. 8, Evaluation Prompt for Evil Expression… · p. 8
B Example Responses
The example-response tables compare outputs with and without evil-vector steering across four instruction-tuned models.
- Table 1 presents responses with and without evil-vector steering for Qwen2.5-7B-Instruct and Llama-3-8B-Instruct.Source: Table 1 · p. 9
- Table 2 presents responses with and without evil-vector steering for Mistral-7B-Instruct and Gemma-2-9B-it.Source: Table 2 · p. 10