Because humans live in groups, they must grapple with who is in charge and how to get along with each other. All social animals have devised various means of answering these basic questions, but humans have the added complexities associated with the use of language and argument. This course aims to show how basic problems of sociality play out in common contemporary interactions such as getting help from others, enforcing rules and obligations, providing advice, and changing opinions. It covers theories of message production and of message effects, all of which are evaluated from evolutionary, social, and cognitive meta-perspectives.