Changing Attitudes About a Pro-Environmental Proposal Concerning Solar Power: The Self-Validating Role of Ingroup Versus Outgroup Sources.

BACKGROUND: In this study, we examined whether a persuasive message in favor of a pro-environmental proposal could influence attitude change through a self-validation process when individuals were told that the source of the proposal belonged to their ingroup (vs. their outgroup).

METHOD: Participants read a message that advocated for the use of solar power. Immediately following the message, participants were asked to list their thoughts regarding the persuasive proposal. A thought favorability index was created for each participant. Following the thought-listing task, participants received the experimental manipulation (i.e., ingroup vs. outgroup source) based on the minimal group paradigm, after which they reported their attitudes towards the proposal.

RESULTS: A regression analysis showed the predicted interaction between thought favorability and type of source (i.e., ingroup vs. outgroup) on attitudes towards the solar power proposal. According to our expectations, thought favorability was a better predictor of attitudes for participants in the ingroup (vs. outgroup) source condition.

CONCLUSIONS: Attitudes can be polarized as a function of ingroup versus outgroup differentiation through a self-validation process.