It perhaps goes without saying that society is collectively failing to meet the challenges posed by climate change and natural resource management, among other issues. Stagnated efforts may in part be driven by social processes that have been shown to shape whether, how, and to what extent individuals engage with environmental issues. In light of these stalled efforts to advance positive change, there is a pressing need to broaden our understanding of the normative processes that support the formation and maintenance of situation-appropriate social norms. In this dissertation, I integrate research from various fields to explore the role of interpersonal communication as an underutilized application of social influence and its capacity to support widespread cooperation. Specifically, I focus on what drives individuals to intentionally communicate with others across different domain-specific issues as well as examine existing norms concerning angling behavior and the use of increasingly popular mediums and channels of communication, such as photographs shared on social media. In Chapter II ("A Few Bad Apples or Rotten to the Core"), I reveal how variation in consumers' attribution of blame, either to a handful of individuals or else corrupt corporate culture, drives responses to unethical environmental corporate wrongdoing, including engagement in word-of-mouth behavior (e.g., badmouthing). In Chapter III ("Peer Pressure on the Riverbank"), I show how efficacy beliefs and reputation concerns predict recreational anglers' willingness to impose social sanctions on others' inappropriate behavior. In Chapter IV ("Fishing for a Photograph"), I reveal how individuals misperceive prevailing norms relative to catch-and-release handling practices. Finally, in Chapter V ("Communicating for Conservation"), I provide a theoretical and empirical overview of interpersonal communication concerning environmental collective action problems, categorize the normative nature and implications of information exchanged during a conversation, and suggest application insights for conservation managers and practitioners. Collectively, these chapters shed light on some of the factors that shape individuals' willingness to communicate with others and how social norms are created, maintained, and circulated through interpersonal interactions. This dissertation contains both previously published work (Chapters II, III are co-authored publications) and unpublished material (Chapter IV, Chapter V).