Levels of verbalisation

I've been reading Protocol Analysis to get a better sense of the state-of-the-art when it comes to think-aloud / talk-aloud protocols for training and user testing.

One interesting concept is the different levels of verbalisation:

1. Vocalisation of the actions being taken during a particular task.  There are no intermediate cognitive processes that require special effort to communicate.
2. Vocalisation of the thoughts that occur during a particular task.  This may require decompressing internal formats or recoding non-verbal information (e.g., describing a smell).
3. Vocalisation of the explanations for thoughts, ideas, motives, during a particular task.  This requires going beyond information stored in short-term memory.