Common ground in the interdisciplinary research process is the pivot from disciplinary to interdisciplinary perspective. As thinking moves from disciplinary to interdisciplinary, what is the shape or structure of attention, how does intellectual content transform in the attending process? Four common ground techniques--extension, redefinition, transformation, organization--are characterized as modifications of attention using Gestalt theoretical principles and phenomenology. The illustrated attentional transitions support the claim that interdisciplinary common ground is a cognitive achievement.