Promoting Action by Discourse

This chapter examines efficacy in public communication, with particular attention to scientific communication on complex issues such as climate change and health. It has been seen that simply communicating data, even if correct, is not enough; the human cognitive system must be taken into account to ensure the efficacy of the communication. Policymakers have access to multiple instruments for guiding social behaviour, including laws, regulations, economic incentives, and strategies informed by economics, cognitive science, and communication psychology. Among these, nudging (together with other behavioural insights) has emerged as a widely used approach, which can be complemented by insights from psychorhetoric. The analysis emphasizes that effective policy design requires attention not only to cognitive mechanisms but also to communicative factors and heuristics that shape how messages are interpreted. The same cognitive process may yield divergent outcomes when communicative conditions are altered, thereby affecting efficacy. The chapter further highlights the constructive use of behavioural insights in shaping the meaning attributed to interventions, drawing on social experiments to illustrate the crucial role of context. It concludes by identifying choice architecture as a key field for research and application, underscoring the centrality of communication in the success of public policies.