Accuracy Motivation, Consensus Information, and the Law of Large Numbers: Effects on Attitude Judgment in the Absence of Argumentation

This study examined the influence of majority opinion on attitudes in the absence of persuasive argumentation. Participants who were either high or low in accuracy motivation were presented with an opinion poll that conveyed consensus information and the sample size of the poll. According to the law of large numbers (LLN), large polls provide more reliable estimates of consensus than smaller polls. Results generally supported predictions. Less-motivated participants tended to be influenced by consensus regardless of poll size, whereas highly motivated participants based attitudes on this information only if the poll was reliably large. Thus, participants who were highly motivated seemed to appreciate the LLN when making their attitude judgments. Consistent with the heuristic-systematic model, process measures indicated that consensus influenced attitudes through both heuristic and biased systematic processing under high motivation, but it influenced attitudes only via heuristic processing when motivation was low.