Latent Ordinal Evidence, Misaligned Outputs: Inference-Time Ordinal Lens Alignment for Multimodal LLMs
TL;DR - Multimodal LLMs encode strong ordinal information for tasks such as age estimation and disease grading, but their digit-token outputs fail to reflect it. Ordinal Lens Alignment (OLA) recovers this evidence at inference time without modifying the model backbone.
- Hidden states yielded ordinal labels with Spearman correlation up to 0.938 across four benchmarks and four MLLM backbones.
- Native outputs lagged linear probes by 16–77 absolute accuracy points because the unembedding layer largely filtered out the ordinal direction.
- OLA trains lightweight lenses on intermediate-to-deep decoder layers, fuses their predictions, and adjusts only digit-token logits during generation.
- It outperformed the LoRA-tuned OrderChain baseline in most settings and improved over an offline lens in every evaluated setting.