# Mechanistic shaping

Training usually rewards only correct answers, so a model can learn shortcuts such as reading a chest drain to call pneumothorax. Mechanistic shaping writes an interpretability-derived internal concept direction into the loss: reliance shaping lowers how much a model depends on a concept, expression shaping lowers how much it expresses one. On real chest X-rays, reliance shaping beat standard training and the best of several prior methods, and exceeded a soft ceiling from balanced-data training; in language models it curbed preference-optimization sycophancy, while expression shaping kept cheating on a Countdown task low.

Training usually rewards only correct answers, so a model can learn shortcuts such as reading a chest drain to call pneumothorax. Mechanistic shaping writes an interpretability-derived internal concept direction into the loss: reliance shaping lowers how much a model depends on a concept, expression shaping lowers how much it expresses one. On real chest X-rays, reliance shaping beat standard training and the best of several prior methods, and exceeded a soft ceiling from balanced-data training; in language models it curbed preference-optimization sycophancy, while expression shaping kept cheating on a Countdown task low.