Potential Limitations of Verbal Protocols in Design Experiments

Abstract

Contradictory results of a recent design stimulation and creativity experiment prompted us to re-examine our chosen methodological approach, namely the use of verbal protocols. We used verbal protocols to study design cognition associated with stimulus use. Our results showed that use of stimuli did not increase concept creativity, contradicting much of the design literature. After eliminating other possible errors, we re-examined the experimental methodology to identify potential design-specific limitations associated with verbal protocols. Many researchers have used verbal protocol experiments, also known as talk-out-loud experiments, to study cognitive processes, as there are few other methods to study internal cognition. While verbal protocols are a widely debated method, research has been done to validate them, and precautions can be taken to mitigate associated risks. Based on reviewing the literature and our own experiences, we have developed design-specific guidelines for the use of verbal protocols. We also outline future work required to explore and understand the suitability of verbal protocols for design studies. Despite potential limitations, verbal protocols remain a valuable and practical tool for studying design cognition and therefore should not be discarded.