AbstractsMedical & Health Science

Adopting or sustaining appropriate levels of health behavior can offer numerous physical and mental health benefits. Unfortunately, most people are unable to initiate or maintain their health behavior. The present thesis aimed to explain and improve behavior change in the context of six kinds of health behavior (face mask wearing, fruit and vegetable consumption, physical activity, hand hygiene behavior, sun screen use, and dental flossing) among Chinese samples, using the Health Action Process Approach (HAPA) as a theoretical backdrop. To examine psychosocial predictors of face mask wearing, fruit and vegetable consumption, and physical activity, three longitudinal studies were conducted based on the HAPA among Chinese young adults. The first longitudinal study represented in Chapter 2 is the first to identify both motivational and volitional predictors of face mask wearing to avoid exposure to polluted air with a structural equation model. Results from this study showed that self-efficacy and risk perception jointly predicted intention and planning and action control as two parallel mediators predicted face mask wearing. The second longitudinal study described in Chapter 3 aimed to explore the roles of action control and action planning between intention and fruit and vegetable intake. The results revealed action control and action planning to sequentially mediate between intention and subsequent fruit and vegetable consumption, controlling for baseline behavior, which suggested that planning may be more proximal to behavior than action control. The specific aim of the third longitudinal study described in Chapter 4 was to examine the roles of motivation, planning, and self-efficacy as well as mechanisms that operate in the change of physical activity levels. The study found that only when people are motivated to become more active, a mediation from self-efficacy via planning to physical activity seems to work. All the findings from the three longitudinal studies supported the HAPA as a useful framework to explain diverse health behaviors, with a focus on planning and action control, which might be influential in the adoption and maintenance of health behavior. To improve hand hygiene behavior, sun screen use, and dental flossing by a theory-guided self-regulatory intervention, three randomized controlled trails were conducted. The first experimental study (Chapter 5) aimed to examine the effectiveness of a planning technique in the new context of hand hygiene among adolescents. Results from the study replicated the previous studies in other domains which confirmed the usefulness of a planning intervention in the context of hand hygiene. It also found that changes in planning operated as a mediator between experimental conditions and changes in behavior. The second experimental study (Chapter 6) aimed to compare the effect of a self-regulatory intervention with focusing on planning sun screen use with a standard educational condition. The results also replicated planning as a mediator between conditions and later…