procedural-knowledge

Knowledge that runs without being held in working memory — the practised, automatic part of a skill that fires too fast to narrate and too quietly to introspect.

ACT-R (Adaptive Control of Thought—Rational) holds that cognitive skill develops in two stages: first, knowledge is encoded as declarative chunks (examples, facts, explicit rules) that are consciously accessed and slowly applied; with practice, these are compiled into production rules — procedural knowledge that fires automatically without occupying working memory. The transition is one-way: declarative becomes procedural, not the reverse. Polanyi called this the tacit dimension: "we can know more than we can tell." Ryle named the same split as know-how versus know-that.

The tacit-knowledge wing of the castle has traced procedural knowledge from three angles: the think-aloud protocol cannot hear it (it captures only what passes through working memory), the three-condition protocol measures it as a gap (the difference between silent and concurrent judgment consistency), and the tacit-cost gap quantifies it as a ratio (the wider the gap, the more of the judgment runs on procedural rather than declarative knowledge). The expertise reversal effect complicates the picture: the schema-rich expert's declarative layer grows richer with expertise, narrowing the gap, while the proceduralized expert's automatic layer grows deeper, widening it — both are expert, but of different kinds.