Short Definition
Thin modality towers are lightweight modality-specific encoders that project inputs such as images or audio into a shared model space.
Intuition
The modality adapter stays relatively simple, while the large shared model does more of the representation and reasoning work.
Technical Definition
A thin modality tower uses comparatively small preprocessing or projection modules to map non-text inputs into embeddings consumed by a shared decoder or backbone.
Example
Inkling uses relatively simple image and audio towers before projecting modalities into a shared hidden space.
Common Misunderstandings
Thin modality towers do not mean multimodal understanding is simple.
They are an architectural tradeoff, not a universal best practice.