The influence of others : the impact of perceptions of others' opinions on individual attitudes and behavioral intentions
Keywords: Communication.

This dissertation consists of three chapters, which explore the impact of others' attitudes on individual attitude and behavioral intention, with an emphasis on the importance of optimal measurement for public opinion research. The first chapter deals with the role of the perception of a group of expert sources on individual opinion on a public issue. Specifically, I examine whether perceiving more agreement among a group of experts (i.e., natural scientists studying global warming) is associated with more acceptance of the consensus view of the experts, but primarily among individuals who trust the experts. Using data from surveys of nationally representative samples of U.S. adults conducted between 2010 and 2015, I show that more perceived agreement among scientists was associated with more public adoption of the consensus view of the experts, regardless of whether perceived agreement was measured with a dichotomous measure of perceived agreement among experts or a continuous, percentage measure of perceived agreement. However, only the continuous measure revealed the expected moderation of the relation by trust in scientists, suggesting that continuous measure may capture individual perceptions more veridically. Furthermore, the continuous measure indicated more perceived agreement among scientists and thereby suggests that public perceptions of global warming experts may not be as inaccurate as the dichotomous measure has suggested. Next, I turn to another context, the domain of marketing, to explore the role of individuals' perceptions of other people's liking of a product/brand in their own liking of the product/brand and related behavioral intentions. To do this, I examined the literature of marketing, particularly focusing on the literature of advertising effects. By reviewing research on the outcomes of advertising and the mechanisms underlying the effectiveness, I suggest there are some important but under-researched topics related to advertising effects. In particular, I suggest that, whereas some research has examined the role of perceptions of others' attitudes, for example focusing on the effect of other customers' endorsement or evaluations on the product (e.g., customer reviews), there is not enough research to understand how this perception may play a role in the effect of advertising. Specifically, the question of how advertisements may influence consumer attitudes and behaviors via the perception that their products are liked by many people (i.e., perceived brand popularity) has not been addressed yet. Further, the examination of previous research indicates some methodological limitations in testing advertising effectiveness. In the third chapter, therefore, I explore the role of the perception of other people's liking of the brand in advertising effectiveness. In particular, drawing from social influence theory and extending Nelson's (1974) theory of advertising, I examine whether the effects of advertising on consumer attitude and behavioral intention are mediated by the extent to which consumers think the brand is popular among other people. Using national survey data of American adults, this study shows that when advertising induces the perception of brand popularity, this perception positively influences individual own attitude toward the brand, which in turn enhances behavioral intentions related to the brand. However, whether advertisement can induce perceived brand popularity seemed to depend on characteristics of advertisement: Only one of the two ads used in this study had significant impact on signaling brand popularity. In addition, the effects of advertising were moderated by perceived humor of the ad and previous exposure to the ad, but such effects were not shown consistent between the two ads, pointing to the complex nature of the effect of moderators in advertising. Additional analyses were conducted using diverse indicators of critical constructs (i.e., brand attitude, purchase intention, etc.) to examine the various potential outcomes of advertising. The result suggests that advertising's influence is indeed more broad and far-reaching than previously assumed. For example, it was shown that exposure to advertisements could enhance respondents' attitudes and behavioral intention for general products from the company (but not necessarily enhancing those for the advertised product). Implications of the findings were discussed in terms of the critical role of perceptions of others' attitudes in advertising effectiveness and the importance of measurement for better capturing the whole effects of advertising. Therefore, the studies together provide important insights into our understanding of the impact of others on various aspects of daily life. Indeed, this perception of others—regardless of whether it is about the experts' opinions about public issues or it is about other people's product preferences and brand choice—seems to exert a powerful influence on individual's beliefs, attitudes, and behaviors.