protocol analysis

The study of what the mind says while it works — asking the expert to narrate aloud and checking whether the narration captures the judgment or merely reconstructs it.

Protocol analysis (Ericsson & Simon, 1980, 1993) distinguishes three types of verbal report. Type 1 — concurrent think-aloud, reporting what passes through working memory without explaining why — is designed to be minimally reactive. Type 2 and 3 ask the expert to explain or give retrospective accounts, and these are where reconstruction creeps in. The framework's core claim: procedural knowledge is not held in working memory in a verbalisable form, so concurrent verbalisation captures the explicit layer (the questions asked, the options weighed) but not the tacit layer (the automatic pattern-matching that runs silently). The castle's three-condition protocol — silent, concurrent Type 1, retrospective — is the design that names two gaps: the reconstruction cost (concurrent vs. retrospective) and the tacit cost (concurrent vs. silent), two gaps that name the two layers.