Why do clarification requests look different at each communication level?

"A Recipe for Annotating Grounded Clarifications" (Benotti & Blackburn 2021, arXiv:2104.08964) maps dialogue clarification mechanisms onto Clark's (1996) action ladder of communication, revealing that clarifications are not a uniform speech act but are grounded in distinct modalities at each level:

• Level 1 (attention): grounded in socioperception — achieving joint attention
• Level 2 (signal): grounded in hearing — recognizing what was said
• Level 3 (meaning): grounded in vision — recognizing referents in the world
• Level 4 (action): grounded in kinesthetics — moving and acting in the world

Causality flows upward through these levels — you must achieve attention to enable signal recognition, signal recognition to enable meaning recognition, meaning to enable action uptake. A clarification at any level is triggered when positive evidence of understanding at that level is absent.

Key implications:

Humans switch between clarifications grounded in different modalities seamlessly but systematically. The most common realization of clarification requests is declarative form, not interrogative — form is unreliable as an indicator of clarification function. This means current LLM dialogue systems that detect clarification needs via question detection miss most clarifications.

The paper's formal recipe — "a subsequent turn is a clarification grounded in modality m if it cannot be preceded by positive evidence of understanding in m" — provides a testable criterion that could inform dialogue system design.

This extends Why do language models skip the calibration step? by specifying that repair itself is multimodal and hierarchical, not a single mechanism. It also connects to Do language models actually build shared understanding in conversation? — LLMs cannot ground clarifications at levels 1, 3, or 4 because they lack the relevant modalities (socioperception, vision, kinesthetics), leaving only level 2 (text-as-signal) available.