The role of tangibility and iconicity in collaborative modelling tasks

In collaborative modelling, a group of stakeholders construct a shared graphical representation of a system. In practice, not all stakeholders may fully comprehend the modelling language. This may reduce their participation, which results in reduced model quality. Our goal is to investigate which features of modelling languages help stakeholders contribute to collaborative modelling tasks. Earlier research shows that iconicity, ie similarity between sign and object, improves understandability, and that tangibility, ie physical graspability of signs, improves participation of stakeholders. In this paper we report on a 2x2 factorial experiment that explores for the first time the interaction between iconicity and tangibility in the context of collaborative modelling. In this experiment, tangibility promoted equal participation, and iconicity had a beneficial impact on understandability, modelling speed and model quality. Notably, tangibility magnified the effects of iconicity. We relate these results to previous findings and interpret them in terms of existing theories.