One of the most accessible interpretability windows: visualizing attention — drawing the weights that show which tokens the model "looked at" when processing each word.
What you see
For each token, attention weights reveal what it drew context from:
"The cat sat because it was tired."
↑
"it" attends strongly to → "cat"
Tools like BertViz render these as heatmaps or connection lines across the attention heads, and different heads specialize — one tracks grammar, another long-range references, another quotation matching.
Useful, but not the whole story
| Strength | Limit |
|---|---|
| Intuitive, visual | Attention ≠ explanation |
| Reveals head specialization | High weight isn't always "why" |
| Great teaching tool | Misses feed-forward computation |
Attention maps show where the model looked, not what it concluded. They're a flashlight into one part of the machine — real understanding needs circuits too.
Related: The Attention Mechanism · Mechanistic Interpretability · How Transformers Work