Heuristic versus systematic information processing and the use of source versus message cues in persuasion.

TLDR

The study manipulated communicator likability, argument quantity, and participant involvement across two experiments to assess how systematic versus heuristic processing influences persuasion. High‑involvement participants were more persuaded by a greater number of arguments, whereas low‑involvement participants were more persuaded by a likable source, confirming that systematic processing dominates at high involvement and heuristic processing at low involvement, and that content‑mediated change is more durable.

Abstract

In Experiment 1, subjects read a persuasive message from a likable or unlikable communicator who presented six or two arguments concerning one of two topics. High response involvement subjects anticipated discussing the message topic at a future experimental session, whereas low involvement subjects anticipated discussing a different topic. For high involvement subjects, opinion change was significantly greater given six arguments but was unaffected by communicator likability. For low involvement subjects, opinion change was significantly greater given a likable communicator but was unaffected by the arguments manipulation. In Experiment 2, high issue involvement subjects showed slightly greater opinion change when exposed to five arguments from an unlikable (vs. one argument from a likable) communicator, whereas low involvement subjects exhibited significantly greater persuasion in response to one argument from a likable (vs. five arguments from an unlikable) communicator. These findings support the idea that high involvement leads message recipients to employ a systematic information processing strategy in which message-based cognitions mediate persuasion, whereas low involvement leads recipients to use a heuristic processing strategy in which simple decision rules mediate persuasion. Support was also obtained for the hypothesis that content-mediated (vs. source-mediated) opinion change would shower greater persistence.