We live in an era in which the processes of content production and the patterns of media consumption are changing rapidly. Even the most seasoned media professionals are struggling to determine what the media landscape of the future will look like and what business models can be used to support it. In addition, because of the ubiquity of media in our lives, there is unprecedented questioning of how society is being harmed by certain kinds of media messages like superficial or fake news, negative stereotypes, manipulative advertising, gratuitous violence, sex and the list goes on. Fortunately, scholars have theorized media effects, both positive and negative, in many different ways and produced a very large research literature on if, how much and how the media influence us. The broadly explanatory concepts of theory help us understand some of the underlying ways in which humans respond to and share different types of information, and can help us make some informed predictions about what the future may hold. This course will introduce students to mass communication theory, focus on theories of media effects and how belief or behaviour change has been conceptualized through constructs such as cognition, affect, attitudes, physiology, social norms, policy etc.