A low-dimensional capability score extracted from an LLMA large language model — the neural network behind tools like Claude and ChatGPT, trained on huge amounts of text to predict what comes next.Full definition →'s textual benchmarks via PCA predicts its downstream VLM accuracy across model families — modeled with a per-backbone transfer rate plus an absorption rate for data-scaling efficiency.
The law was fit on 150+ VLMs trained over 34 LLMs from 7 families under one controlled recipe, extrapolates from sub-8B models to 72B backbones, and holds on entirely held-out families.
Base LLMs make better VLM backbones than their instruction-tuned counterparts — higher absorption rates and lower data-scaling decay.
Certain textual benchmarks correlate NEGATIVELY with multimodalA model that works with more than text — reading images, audio, or video, and sometimes generating them too.Full definition → performance, exposing latent benchmarkA standard public test set for comparing AI models — the shared scoreboards behind every "model X beats model Y" claim.Full definition →-gaming in backbone models.
Practical effect: backbone selection becomes a quantitative prediction instead of an expensive trial-and-error training sweep.
Terms in this piece · Glossary
LLM — A large language model — the neural network behind tools like Claude and ChatGPT, trained on huge amounts of text to predict what comes next.
multimodal — A model that works with more than text — reading images, audio, or video, and sometimes generating them too.
benchmark — A standard public test set for comparing AI models — the shared scoreboards behind every "model X beats model Y" claim.
Why it matters
The paper shows a low-dimensional textual capability score (via PCA) predicts multimodal performance across model families and scales up to 72B, letting practitioners pick an LLM backbone for a VLM via prediction instead of expensive trial-and-error training runs.
Key quotes
“We propose the Capability-Driven Multimodal Scaling Law, the first cross-family framework that predicts VLM benchmark accuracy from directly observable textual capability.”
“The framework turns backbone selection from costly empirical sweeps into a principled, quantitative decision.”