Apple paper: top-k logits can leak task-irrelevant info almost as much as residual stream

sineadwilliamso · x · 2026-10-07

An Apple team presented "What do your logits know?" at COLM, using vision-language models to systematically compare how much information survives two natural bottlenecks as it is compressed from the residual stream: low-dimensional tuned-lens projections and the final top-k logits.

Key finding: even the most accessible bottleneck — the model's top logit values — can leak task-irrelevant information from an image-based query, in some cases revealing as much as direct projections of the full residual stream. The authors note direct implications for privacy, fairness, distillation, and interpretability: final logits are far from a minimal information bottleneck, and information the model owner assumed inaccessible can be extracted by users.

Related event: Study: VLM top-k logits leak far more task-irrelevant image information than expected(8 posts)→

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