Abstract
Researchers studying argumentation often make the simplifying assumption that rational persuasion can be studied independently from the processes through which social identities are established and maintained. However, developments in the study of message design, particularly the groundbreaking work of Brown and Levinson (1978, 1987) on politeness, suggests that in practice the multiple functions of messages are intertwined in message structure and effects. In contrast to the view that identity issues distort rational processes in communication, both the communication of identity and the use of identity-based appeals in social influence are best seen as prototypical examples of rationality in message design