In her empirical study, Christina Krause investigates how gestures can contribute to epistemic processes in social interactions. She expands the traditional speech-based approach to analyzing social processes of constructing mathematical knowledge by employing a multimodal perspective. Adopting a semiotic approach, she takes into account two functions of gestures as signs used by the participants of the social interaction: the representational function concerns the ways in which gestures take part in referring to a mathematical object in processes of knowledge construction and the epistemic function relates to the ways in which they can contribute to the performance of collective epistemic actions. The results of this study reveal that gestures influence the epistemic process significantly more than previously thought and indicate factors underlying this influence.