Industry practitioners and social scientists throughout the world have long sought to determine the effectiveness of advertising in this multi-billion dollar industry. For close to a century, many social scientists have debated just how advertising works. One suggested explanation is the hierarchy of effects—that body of literature that posits that audiences go through a variety of stages, namely cognitive, affective, and conative, in responding to advertising, and other persuasive marketing messages. This paper reviews the hierarchy of effects from its beginning at the turn of this century to present-day developments. The paper also examines the controversies surrounding hierarchy models and provides a critique of the evidence supporting its position as an advertising model.