Two-Sided Messages Promote Openness for a Variety of Deeply Entrenched Attitudes

Prior research showed that people holding attitudes on relatively moral topics became more open to two- rather than one-sided messages as the moral basis of their attitudes increased. Across three studies (N = 963), we extend this finding to relatively non-moral topics by demonstrating that two-sided messages can encourage people with strong attitudes indexed by various non-moral attitude strength measures to be more open to contrary positions. Study 1 demonstrated this for four indicators of attitude strength (e.g., certainty). As the strength of one's attitude increased, two-sided messages increased in relative effectiveness over one-sided communication. This was mediated by perceived appreciation for the speaker acknowledging one's view. Study 2 replicated this finding in a preregistered experiment. Study 3 conceptually replicated and extended it to people holding attitudes based on their political identity. Finally, evidence was obtained supporting perceived appreciation (rather than source evaluation) as the key driver of this interactive effect.