Forewarned and forearmed? Two meta-analysis syntheses of forewarnings of influence appeals.

Two research syntheses evaluate the effects on attitudes of forewarning of an influence appeal. In general, warnings appeared to threaten people's attitudes or their self-images, and warning impact depended on which aspect of the self was threatened. When the topic of the appeal was involving and concerned immediate outcomes or when the appeal was actually delivered, recipients appeared to focus on the potential threat to their attitudes, and they responded defensively by cognitively bolstering their own views and resisting the appeal. However, warnings of appeals on less involving topics generated agreement before the appeal was delivered, presumably because these warnings alerted people to the self-image threat of being gullible and preemptive agreement reduced this threat.