The contrast vector method is recommended over PC1 for reproducing the Assistant Axis in different models because it is not guaranteed that PC1 in every model will correspond to an Assistant Axis

Entities in the same semantic neighborhood but without a typed relation to this one — candidates for new edges or unrecognized duplicates.

• Steering vector constructed from all 16 contrastive pairs outperforms most single-pair vectors; best 4-pair vector outperforms full 16-pair vectorfinding0.790
  Demonstrates averaging multiple prompt pairs reduces noise; optimal subset selection further improves performance.
• The first principal component of persona space (the 'Assistant Axis') captures the assistant vs alternative persona distinction consistently across three models with role loading correlations exceeding 0.92finding0.779
  Finding establishing cross-model consistency of the assistant axis as the dominant structure in persona space
• Cosine similarity between Assistant Axis and role PC1 is >0.60 at all layers and >0.71 at middle layer across all three modelsfinding0.774
  Validates that the contrast vector method and PCA-based PC1 capture the same direction
• Our method achieves superior performance compared to Contrastive Activation Addition.finding0.773
  Performance gains over CAA in steering tasks.
• Pairwise correlation of role loadings on PC1 exceeds 0.92 across all model pairs, indicating remarkably high similarity of the Assistant Axis across Gemma, Qwen, and Llamafinding0.770
  Shows the leading component of persona space is model-universal
• A linear preference vector encoding how much a model likes a given task is persona-relative: it activates strongly for creative writing in the assistant but for phishing in the evil personafinding0.763
  Evidence that core representations like preferences are persona-relative, supporting claim that personas gate content of representations
• We hypothesize that the PC1 axis of role space measures deviation from the Assistant personahypothesis0.761
  Motivates computing the contrast vector as the formal Assistant Axis definition
• The Assistant Axis is also present in pre-trained base models, where it primarily promotes helpful human archetypes (consultants, coaches) and inhibits spiritual onesclaim0.750
  Extends the Assistant Axis finding to pre-training, suggesting pre-training rather than post-training creates the axis