The World Health Organization (WHO) promotes physical activity as a primary way to maintain health, but many individuals do not participate in this health-promoting behavior. Despite the potential for public service announcements (PSAs) to communicate health information and promote behavioral change, no prior research on developing video PSAs to promote physical activity was found. The purpose of this quasi-experimental study was to examine how affective and information video PSAs for a public health campaign affect future levels of intention to engage in physical activity. The PSAs were developed and filmed specific for this study using the model of goal directed behavior (MGDB) as the foundation for PSA development. Participants were recruited to view PSAs with the message foci of empathy, fear, information, and combination messages to determine which focus area is perceived to be most persuasive for promoting physical activity. This research examined moderating effects of current physical activity habits related to the duration of physical activity and the covariance with stage of change readiness. Differences in perceived effectiveness between the different message foci were found with participants perceiving the empathy video as most effective, followed by combination, with fear and information being perceived as least effective. For participants who meet WHO recommendations for exercise activity, the PSA based on fear was most effective, with fear also being most effective for those participants right below that level of physical activity. Many participants (61%) had a positive affect while watching the four PSA videos. Social implications related to improving public health communication through video PSAs that effectively promote health behavior change.

Au cours des dernières années, les communautés virtuelles de patients se sont énormément développées sur l'Internet. Ces communautés permettent des échanges fréquents entre les patients, qui peuvent partager des informations liées à la santé dans un environnement interactif. Alors que beaucoup s'accordent sur l'opportunité représentée par ces communautés pour ses utilisateurs, les connaissances sur ce qui détermine l'action collective en ligne des patients ainsi que sur les fondamentaux de l'action collective en ligne dans ces espaces virtuels sont relativement peu développées. En conséquence, ce travail doctoral examine les raisons pour lesquelles les patients interagissent entre eux et comment ils procèdent. En nous appuyant sur le modèle du comportement orienté vers un but, la théorie de la valeur de l'attente, la théorie des forces du champ, les concepts de dons et les interviews menées, nous avons développé un modèle qui examine les interactions en ligne des patients dans un contexte d'action collective en ligne. Une approche multi-méthode, qualitative et quantitative, permet d'explorer les interactions des patients et de mesurer les déterminants de l'action collective en ligne sur ces espaces virtuels. L'analyse qualitative de 54 entretiens menés avec des patients, des proches de patients, des professionnels de la santé 2.0, des médecins et des soignants permet d'affiner le modèle de recherche, qui a ensuite été testé au travers d'une enquête quantitative auprès de 269 patients. Cette recherche contribue à la recherche en systèmes d'information en augmentant nos connaissances sur la dynamique individuelle et les interactions qui entourent les communautés de patients en ligne. / Over the last few years, virtual patients’communities have been developing tremendously over the Internet. These Web 2.0 communities allow frequent interactions among patients, who can share health-related information within an interactive environment. While many agree on the opportunity represented by those communities for its users, we know very little about what determines patients’ online collective action, specifically on virtual communities as well as the fundamentals of online collective action in these virtual spaces. Accordingly, this doctoral work examines why patients interact with others and how they interact on topics related to their disease through these virtual communities. Drawing on the goal-directed behavior (MGB), the expectancy-value (EVT) theories, the field force theory, gift concepts and field interviews, we have developed a model for examining patients’ online interactions and identified gift-giving behaviors in the context of online collective action. A multi-method, qualitative and quantitative approaches, enables us to explore patients’ interactions and measures the determinants of online collective action on these virtual spaces. The qualitative analysis of 54 interviews conducted with patients, patient’s relatives, Health 2.0 professionals, doctors and caregivers allows refining the research model, which has then been tested through a survey handled with 269 patients, members of patient’s communities. This research contributes to IS research by increasing our knowledge regarding the individual dynamics and interactions that surround online patients’ communities.