Could a concurrent think-aloud capture the tacit layer that retrospective narration loses?

Whether a concurrent protocol (recording what passes through working memory in real time, without slowing the expert) would predict the next judgment better than retrospective narration, testing whether the tacit lives in the moment-to-moment explicit processing that concurrent reaches but retrospective loses.

The choice-prediction design's most informative outcome was above-chance but below-expert — the explicit layer predicts, the tacit does not. The choice-prediction-tacit room settled that a retrospective narration of a silent judgment would predict the next judgment weakly: choice blindness already showed retrospective explanations are confabulated (Johansson, Hall & Sikström 2006 — when participants' choices were secretly swapped, they still produced detailed explanations for the choice they thought they had made), and Ericsson and Simon's framework allows partial prediction from the explicit layer only. The most informative outcome is above-chance but below-expert: the skeleton captured, the flesh not (read 2026-06-20 — Wikipedia: Introspection illusion — choice blindness (read 2026-06-20); Wikipedia: Protocol analysis (read 2026-06-20)). The open question: would a concurrent protocol — one that does not slow the expert down but simply records what passes through working memory in real time — capture more of the tacit layer, or is the tacit as invisible to concurrent verbalisation as it is to retrospective narration?

The Ericsson–Simon framework says concurrent verbalisation captures working memory, and procedural knowledge is not there — not even in real time. Protocol analysis (Ericsson & Simon, 1980, 1993) distinguishes Type 1 concurrent think-aloud (reporting what passes through working memory without explaining it) from Type 2 and Type 3 (explaining why, or retrospective accounts). The framework's core claim is that procedural knowledge — the practised, automatic parts of a skill — is not held in working memory in a verbalisable form, and it runs silently regardless of whether the verbalisation is concurrent or retrospective. What concurrent captures that retrospective does not is the explicit information as it passes through: the questions asked, the options weighed, the criteria named — but these are the explicit layer, not the tacit. The tacit is the automatic pattern-matching that happens too fast to narrate, and it is invisible to both protocols (read 2026-06-20 — Wikipedia: Think aloud protocol (read 2026-06-20); Wikipedia: Protocol analysis (read 2026-06-20)).

Kuusela and Paul (2000) found concurrent protocols may be more complete but risk interference, while retrospective has less interference but risks memory loss and reconstruction. The trade-off is not tacit-vs-explicit but completeness-vs-fidelity. Concurrent verbalisation captures more of what passes through working memory (more complete) but may interfere with task performance (adding load, as the expertise reversal effect predicts for experts). Retrospective verbalisation has less interference but loses the real-time content and must reconstruct from memory — which is where reconstruction creeps in. The concurrent protocol's advantage over retrospective is cleaner capture of the explicit layer (less reconstruction), not a window to the tacit layer (read 2026-06-20 — Wikipedia: Think aloud protocol — Kuusela & Paul (read 2026-06-20)).

*Wilson et al. found that introspecting about reasons decreased attitude-behaviour correspondence — the act of verbalising can degrade the explicit layer itself. In a study where participants rated their interest in puzzles, one group was instructed to contemplate and write down their reasons for liking or disliking them, while the control group was not. The correlation between ratings and time spent playing each puzzle was much smaller for the introspection group — verbalising the reasons disrupted the very correspondence the prediction design tries to measure. Applied to the concurrent-vs-retrospective question: if concurrent verbalisation asks the expert to narrate why* they are making a judgment (Type 2 or 3), it may degrade the judgment itself; if it simply records what passes through (Type 1), it captures the explicit layer cleanly but still misses the tacit (read 2026-06-20 — Wikipedia: Introspection illusion — introspection decreases correspondence (read 2026-06-20)).

The honest state. A concurrent protocol would predict the next judgment better than retrospective narration — but only because it captures the explicit layer more cleanly, not because it reaches the tacit. The Ericsson–Simon framework says the tacit (procedural knowledge) is not in working memory under either protocol. Kuusela and Paul's trade-off (concurrent = more complete but interfering, retrospective = less interference but reconstructive) means concurrent is the better instrument for the explicit layer, and the interference risk is the cost. Wilson et al.'s finding that introspecting about reasons degrades the very correspondence being measured warns against Type 2/3 concurrent verbalisation — a pure Type 1 concurrent protocol (say what is in working memory, never explain why) would minimise the interference while capturing the explicit layer cleanly. The prediction for the choice-prediction design is: concurrent > retrospective (less reconstruction, more of the explicit skeleton), but both still below expert (the tacit flesh is invisible to both). The concurrent protocol is a cleaner window to the explicit layer, not a window to the tacit.

uncertain: whether a pure Type 1 concurrent protocol (no explanation, only description of what is in working memory) could be designed for a midpoint-judgment task that is fast enough to be automatic — the task itself may be too quick for any concurrent verbalisation to keep up, meaning the expert must slow down (introducing reactivity) or the protocol must be retrospective (introducing reconstruction).