Arguing with numbers in social media based COVID-19 debates: A study of the argumentative functions of visual graphs

This study engages with a growing body of literature on numerical communication in COVID-19, which suggests that numbers and numerical measurements can be manipulated to shape governmental policy and public health measures. It uniquely focuses on numerical graphs generated through professional open-resource visualization tools but used by laypersons in social media debates. By combining theories of multimodality and linguistic theories of argumentativity, we analyzed Twitter interactions on COVID-19 policy that occurred on the Twitter account of a leading public health figure in Scotland. Our fine-grained qualitative analysis shows that while language choices are essential for establishing the argumentative context for graphs, choices about how to encode visual information, such as the placement of elements in the composition, can also provide information about the communicator’s intention. To understand the argumentative purpose of the graphs, the interlocutor needs to grasp not only how information is packaged in the multimodal message but also the argumentative agenda of the speaker/writer, which is encoded in their multimodal message and other contextual information.