IC-168Control vectors derived from BABI improve GSM8K accuracy and vice versa on Mistral-7B-Instruct, indicating a task-general reasoning direction in the residual stream
Bertram Højer, Oliver Simon Jarvis, Stefan Heinrich
The authors derive a PCA control vector from BABI contrastive pairs and apply it to the GSM8K evaluation, and vice versa. In both directions, Mistral-7B-Instruct shows an increase in logit-based accuracy comparable to the same-task control vector, with similar trends in KL divergence and entropy. This cross-task transfer suggests that the residual stream encodes a direction associated with reasoning more broadly rather than a task-specific feature.
Evidence
interventional
Caveat
The authors note that the model representations are not very robust to the intervention (jagged trend line) and that the cross-task result is observed on a single model (Mistral-7B-Instruct) with a single pair of tasks.