Poison Parasite Running head: THE POISON PARASITE DEFENSE The Poison Parasite Defense: Instilling Persistent Resistance to Persuasion

Relatively little work has examined procedures that produce resistance to the persuasive appeals of one’s opponents. We sought to redress this imbalance by investigating the Poison Parasite Defense (PPD)—a technique that consists of two elements, one poisonous (strong counter information) and one parasitic (associative links between one’s counter claims and the rival position). In three experiments, the combination of these two elements created enduring resistance to an opponent’s message, even when that message was viewed more frequently. In contrast, though effective immediately after their presentation, counter messages lacking one or both of these attributes were ineffective over time with subsequent presentations of the opponent’s message. Discussed are the processes underlying the PPD’s effectiveness and potential uses of the PPD.