Please and no, thank you: politeness norms alter compliance more when refusing than when making or acquiescing to a request.

Research indicates that using polite words does not enhance compliance. However, this work focuses on requests, not responses, which also are compliance-relevant behaviors that might depend on politeness. In 12 experiments (4 preregistered), we examined the role of politeness in compliance by manipulating the politeness of people's requests and responses. Polite requests increased compliance relative to what people wanted to do, d = .95. Adding a polite word to a request, however, did not significantly increase compliance, d = .11. In terms of responses, polite acceptances did not increase compliance, d = .08, but polite declines mattered. Respondents were sooner to decline a request if they could reply with "No, thank you" rather than a less polite "No," d = -.34. These data indicate that politeness norms shape compliance, but the key norm might not be whether people comply with polite others, but rather whether people can politely decline the request.