The effectiveness of health promotion messages targeting youths is largely dependent on the message's degree of success in linking positive consequences with the enactment of healthy behaviors and negative consequences with the enactment of unhealthy behaviors. This project addresses a previously unexplored factor related to the efficiency with which advertised messages succeed in forming such linkages. Specifically, it investigates the influence of linguistic form on youths' abilities to store beliefs about use/users versus nonuse/nonusers. Based on psycholinguistic theory, the following hypothesis is offered for empirical test: messages attempting to link outcomes with affirmative forms of linguistic descriptors denoting use/users (e.g., smoker, sunscreen user) will achieve greater levels of influence on youths' health-relevant beliefs than messages attempting to link outcomes with negated linguistic descriptors (e.g., nonsmoker, non-sunscreen user). As prior research, which has often confounded linguistic form with message frame (e.g., substance use/users = negative outcomes, substance nonuse/nonusers = positive outcomes), offers conflicting recommendations about the use of positive, gain-framed versus negative, loss-framed messages, results of this project promise to help clarify guidelines for optimal message design. Two specific aims are pursued: (1) compare the impact of messages designed to shape beliefs about use/users (e.g., smokers, sunscreen users) in reference to the impact of messages designed to influence beliefs about nonuse/nonusers (e.g., nonsmokers, non-sunscreen users), and (2) assess the relative impact of positive and negative formulations of these basic message types. Two studies employing 6th graders are used to accomplish these aims. The first study (n = 100) tests theoretical hypotheses about the manner in which health-related descriptors of varying linguistic forms are stored in memory. The second study (n =200) utilizes a simulated television-advertising paradigm to test applied predictions about consequences of differential storage for the effectiveness of health promotion messages. The relative impact of positive and negative formulations of messages about smokers, nonsmokers, alcoholics, non-alcoholics, drug users, non-drug users, sunscreen users and non-sunscreen users on youths' beliefs is assessed in the study.