Disentangling contributions of visual information and interaction history in the formation of graphical conventions

Drawing is a versatile technique for visual communication, ranging from photorealistic renderings to schematic diagrams consisting entirely of symbols. How does a medium spanning such a broad range of appearances reliably convey meaning? A natural possibility is that drawings derive meaning from both their visual properties as well as shared knowledge between people who use them to communicate. Here we evaluate this possibility in a drawing-based reference game in which two participants repeatedly communicated about visual objects. Across a series of controlled experiments, we found that pairs of participants discover increasingly sparse yet effective ways of depicting objects. These gains were specific to those objects that were repeatedly referenced, and went beyond what could be explained by task practice or the visual properties of the drawings alone. We employed modern techniques from computer vision to characterize how the high-level visual features of drawings changed, finding that drawings of the same object became more consistent within a pair of participants and divergent across participants from different interactions. Taken together, these findings suggest that visual communication promotes the emergence of depictions whose meanings are increasingly determined by shared knowledge rather than their visual properties alone.