Syntactic Indeterminacy, Perceived Message Sensation Value-Enhancing Features, and Message Processing in the Context of Anti-Tobacco AdvertisementsAn earlier version of this manuscript was presented at the 2004 National Communication Association Annual Convention in Chicago, IL, November 11–14, 2004

Fast-paced and arousing anti-drug ads, considered to have high perceived message sensation value (PMSV), enhance message processing and reduce drug use among young adults. Studies have yet to explore the relationship between specific, PMSV-enhancing message features and outcomes related to persuasion. Messaris' (1997) concept of syntactic indeterminacy provides one plausible explanation for why message features contained in high PMSV ads might enhance message processing and subsequent changes in attitudes and behavior. The study explored this explanation by coding specific anti-tobacco ads for PMSV-enhancing features, merging these codes to a telephone survey among teens, and testing the relationship between message features and processing. The number of unrelated cuts and the use of suspenseful features (intense imagery and a second-half punch) increased message processing among older teens. An additive index comprised of these features was associated with message processing among both younger and older teens. Theoretical and practical implications are discussed. Keywords: Syntactic IndeterminacyMessage ProcessingMessage Sensation ValueMessage FeaturesCampaigns The author would like to thank Alan Sillars and two anonymous reviewers for their valuable comments on earlier versions of this paper. In addition, the author is grateful to Lisa Ramsey, Jared Yarsevich, and Amy Ward for assistance in coding, and especially to Lee Humphreys for invaluable contributions to the paper's conceptual development and implementation of coding procedures. Finally, the author would like to thank Matthew Farrelly and the Florida Department of Health for making the data available, Paul Messaris for insightful comments on an earlier version of the paper, and David Sly for the original study design and data collection. Notes An earlier version of this manuscript was presented at the 2004 National Communication Association Annual Convention in Chicago, IL, November 11–14, 2004 1. Each ad in this study's sample coded as "acted out" also conveyed the ad's central meaning verbally or with text. 2. Morgan et al.'s (2003) "unexpected format" definition read as follows: "If the images and the message could be interchangeable with a number of other antidrug PSAs, it is 'expected,'" (p. 519). 3. Response rate calculations account for parent refusals, child refusals, and failure to contact after five call-backs. Additional informationNotes on contributorsJeffrey D. Niederdeppe Jeffrey D. Niederdeppe (M.A. in Communication, University of Pennsylvania) is a Ph.D. candidate at the Annenberg School for Communication at the University of Pennsylvania. The data were made available to the author during his time at RTI International, a not-for-profit research firm in Research Triangle Park, NC, as part of a contract with the Florida Department of Health to evaluate the Florida Tobacco Control Program (FTCP)