INFORMATION PROCESSING UNDER UNCERTAINTY: MASS MEDIA AND INTERPERSONAL COMMUNICATION EFFECTS ON RESPONSE TO NEAR PREDICTIONS OF EARTHQUAKES

This study examines the effectiveness of different patterns of communication in disseminating information and evoking public response to near predictions of earthquakes. These patterns of communication include: (1) interpersonal discussion supplementing the mass media (a two-step flow model); (2) exclusive reliance on the mass media (a one-step flow model); and (3) disproportionate reliance on interpersonal discussion (rumoring). Specifically, we examine the relationship between patterns of communication use and awareness of near predictions, understanding of near predictions, and the decision to adopt personal and preparedness measures.; The data for the study were obtained from a sample survey of 1450 Los Angeles County residents conducted in February and March, 1977. The findings describe the public state of mind approximately one year after the announcement of the southern California Uplift, and from one to three months after the period of concern with the Minturn forecast.; The study revealed that the majority of Los Angeles County residents have heard at least one prediction about earthquakes in the southern California area during 1976. The mass media, in particular television, was most frequently mentioned as the chief source of information on prediction announcements.; While few respondents mentioned "people" as their chief source of information on prediction announcements, the majority of respondents indicated that they had discussed the earthquake possibility within informal networks. The majority of people in the sample supplemented the mass media with interpersonal discussion, which suggests that the use of the media in conjunction with discussion is the most effective way to arouse public awareness of prediction announcements.; The importance of supplementing the media with interpersonal discussion is illustrated by the fact that people who rely disproportionately on discussion are less likely to understand the significance of the earthquake threat than people who receive information from the mass media. However, the data indicate that exclusive reliance on the media are inadequate to stimulate people to take personal preparedness measures. People who rely exclusively on the media are less likely to take measures to prepare for a future quake than people who engage in interpersonal discussion.; Perception of the earthquake threat as a relevant concern was found to influence whether people verify media reports through interpersonal channels. People who understand the significance of the current threat and people who have prior earthquake experience more often supplement the media with interpersonal discussion than people who do not perceive the earthquake threat as personally relevant.; The importance of interpersonal discussion as a supplement to the media is further illustrated by the influence of social circles upon decision-making about the earthquake threat. The data suggest that social circles, formed on the basis of a common interest in earthquake matters, can motivate people to seek additional information on earthquake topics. In addition, participation in such circles may serve as a source of social support for people who perceive the earthquake threat as personally relevant. Participants are more likely to understand the significance of prediction announcements and to prepare for a future quake than people outside these social circles.; We conclude that social circles based upon an incipient interest in earthquake matters can help mobilize public response to earthquake predictions in one of two ways. First, through a network of overlapping circles, the definition of the situation as "threatening" can be disseminated to other segments of the public. Second, by serving as models or prototypes of imitation, social circles can legitimate earthquake preparedness as a proposed line of action, thereby influencing others to overcome the normalcy bias.