Much research confirms that high conscientiousness is related to decreased mortality risk, in part because conscientious people are more likely to engage in salubrious health behaviors and maintain healthy social support networks. High neuroticism is associated with decreased subjective well-being (SWB) and poorer self-rated health, but there is dispute over the extent to which this reflects actual health problems and increased mortality risk, or heightened sensitivity to somatic symptoms without a true increase in measurable disease and mortality risk. Associations between combinations of conscientiousness and neuroticism and well-being, however, have received relatively little attention. Here, the concept of “healthy neuroticism” was tested, which proposes that the combination of high conscientiousness and high neuroticism is health protective. Survival and regression analysis to were used examine whether “healthy neuroticism” in adulthood (1940) was related to mortality risk and well-being in the lifespan Terman data (N=1528). Following previous literature, the interaction of conscientiousness and neuroticism was modeled via linear and spline terms (which isolates the interaction for participants high in conscientiousness and neuroticism). Contrary to previous theory, results showed that combinations of high conscientiousness and neuroticism were related to worse subjective well-being, particularly for men. Because trait interactions differentially predict subjective well-being and mortality risk, results suggest that subjective and objective measures of health are distinct, with implications for lifelong models of health and well-being.

Through two studies, this project tested the idea that it is the convergence of individual differences and social environmental factors across extended periods of time that are pivotal in influencing how active a person is at any given time and the long-term health-related outcomes associated with different activity patterns. The first study developed archival data refined from the Terman Life Cycle study, which followed 1,528 individuals from childhood in 1922 through death. Growth curve analyses, hierarchical linear regression, and survival analyses were used to investigate patterns of physical activity across adulthood, from average age 25 to age 61, to examine individual psychosocial differences, and to determine how different trajectories relate to health, well-being, and longevity across the lifespan. There was a general pattern of decelerating decline in activity with age, but substantial individual variation that could partly be explained by child and adult psychosocial variables. Childhood energy and sociability, adult extraversion and neuroticism for males, and adult self-rated health and mental adjustment for females were strong predictors of levels and changes in physical activity. Active individuals were more likely to be healthy at midlife and old age, even after controlling for baseline health. Importantly, maintaining or increasing activity related to better health in older age, and lower mortality risk. The second study used a cross-sectional assessment to determine personality characteristics that theoretically and empirically distinguish different activity patterns (active, sedentary, or variable), and to examine links among personality, physical activity, and health. A more active personality strongly correlated with better self-rated health and well-being, fewer perceived barriers and more perceived benefits to being active, and better social relationships. In both studies, personality impacted both physical activity levels and health, and physical activity consistently related to better health outcomes, including higher self-rated health, subjective well-being, and increased levels of energy. All together, the studies suggest that health outcomes relate to physical activity trajectories, but this may depend on the fit between the person and subsequent experiences.

Modern populations face high levels of mental health challenges, chronic diseases, and premature death due to preventable conditions. Advances in theory and methods suggest that optimal solutions to these problems will be multifaceted, targeting multiple behaviors and ways of thinking simultaneously. One promising, widely-used approach addressing modern health problems at multiple levels involves community gardens. Utilized in the United States since the 1890s, community gardens are thought to promote community cohesion, mental wellness, and physical health. Do these programs work? If so, what is it about community gardening that promotes thriving? This project addressed these questions using a controlled experimental design, with extensive valid assessment. Participants were randomly assigned to one of five health interventions: community gardening, physical activity, social film club, exposure to nature, or growing a living thing. Each comparison group was designed to rule out or isolate an element of community gardening that may be a cause of observed correlations with good health. After completing a pretest and attending a workshop, participants engaged in their health behavior two hours a week for four weeks. They then completed a posttest. Participants also completed a subset of measures during the intervention period and three weeks after the conclusion of the intervention. Results showed that, regardless of experimental condition, participants improved in emotional well-being, conscientiousness, social relationships, environmental identity, and self-reported health from pre- to posttest. Though the omnibus ANOVA suggested differential group change in environmental identity (such that the garden and nature groups increased compared with other groups), follow-up analyses did not reach statistical significance. There were no changes in sleepiness, physical activity, or produce consumption. Though results were equivocal, this study is the first true experiment attempting to tease apart the causal mechanisms of community gardening in relation to health and wellness. Thus, this dissertation provides a framework—with measures and models—for researchers studying the effects of community gardening and similar broad health interventions. Rigorous research on whether and why community gardening promotes health is still in its budding stages, and continued research attention is warranted considering the potential implications for individual and community health.

Primary disease prevention requires complex health interventions that influence multiple behaviors simultaneously. Research finds conscientiousness consistently associated with better health behaviors, improved health, and longevity (Friedman & Martin, 2011). A 6-week experimental longitudinal study tested whether a self-regulation training intervention would boost conscientiousness. Changes in broad trait conscientiousness and five underlying facets (perseverance, self-control, orderliness, self-efficacy, and responsibility) were examined. As predicted, the treatment group showed a trend for increasing perseverance compared to the control group, though no differences were found in the other facets nor broad trait conscientiousness. Changes in health behavior revealed that treatment participants also improved in sleep quality relative to control participants. Self-regulation training should be further explored as a viable means for increasing perseverance and improving physical health. Other methods for increasing conscientiousness should also be considered as a prime means for enhancing health interventions.