Can concurrent verbalization reveal design cognition?

We advance a view that design is a combination of many types of thinking, maintaining that concurrent verbal reports are best at revealing particular types of thinking (specifically the short term focus of the designer). There are two issues of using concurrent verbal reports to elicit types of design thinking: (1) do the words 'thought aloud' accurately reflect the design thinking? (2) does a concurrent verbal methodology actually affect the designing it seeks to reveal? In our analysis of Dan's protocol we show how the interaction between design problem and design solution is effectively handled by Dan- and revealed by concurrent verbalization - but how aspects of design thinking such as perception and insight, are not elicited by concurrent verbalization. We go on to show how the design task changes as a result of the designer having to continually think aloud, with 'normal' activities like negotiation and displacement being impaired. We conclude by identifying a need for protocol analysis in design to be specific about the questions it addresses.