nlvr (natural language for visual reasoning)
**NLVR** (Natural Language for Visual Reasoning) is a **benchmark task requiring models to determine the truth of a statement based on a *set* of images** — testing the ability to reason about properties, counts, and comparisons across multiple disjoint visual inputs.
**What Is NLVR?**
- **Definition**: Binary classification (True/False) of a sentence given a pair (or set) of images.
- **Task**: "The left image contains exactly two dogs and the right image contains none." -> True/False.
- **NLVR2**: The version using real web images (instead of synthetic ones) to test robustness.
**Why NLVR Matters**
- **Set Reasoning**: Unlike VQA (one image), NLVR requires holding information from Image A while analyzing Image B.
- **Quantification**: Heavily tests counting and numerical comparison ("more than", "at least").
- **Robustness**: Reduces the ability to cheat using language biases alone.
**NLVR** is **a test of comparative visual cognition** — validating that an AI can perform logical operations over multiple observations.