RESUMO
Background: Many studies suggest a link between gratitude and life satisfaction, including experimental tests of gratitude interventions. This paper presents a systematic review of recent literature on the influence of gratitude on life satisfaction. The aim of this research is to better understand the nature of the relationship between gratitude and life satisfaction and to evaluate the state of literature. Methodology: A systematic search was conducted using four databases (APA PsycInfo, Scopus, Web of Science, and EBSCO), targeting articles published since 2010. Correlational studies were included if they used the GQ6 measure of gratitude and the Satisfaction With Life Scale (SWLS). Intervention studies were included if they reported effects of a gratitude manipulation on SWLS scores. Forty-four articles (N = 16,529) focusing on gratitude and life satisfaction were ultimately selected. Among the selected studies, 18 employed experimental designs and 26 were cross-sectional studies. Five studies also presented cross-lagged analyses from two or more timepoints. Results: The review indicated a substantial positive correlation between gratitude and life satisfaction. Various potential mediators were also identified, including meaning in life, social support, and self-esteem. Some experimental research suggested that gratitude interventions may increase life satisfaction compared to neutral control conditions, although evidence was mixed. There was stronger evidence for these effects in people from Western countries. However, there is no strong evidence that gratitude interventions outperform positively valenced control conditions. Thus, it is possible that the effects of intervention could be caused by demand- or placebo effects. Conclusion and Recommendation: While it is clear that there is a link between gratitude and life satisfaction, the extent to which gratitude causes life satisfaction and the mechanism underlying that link require further exploration. We suggest that experimental work test effects of changes in gratitude that cannot be explained by placebo- or demand effects. We also encourage more interactive interventions as well as research that investigates third variables that could underlie both gratitude and life satisfaction.
RESUMO
The "organic food" market is the fastest growing food sector, yet it is unclear whether organically raised food is nutritionally superior to conventionally grown food and whether consuming organic food bestows health benefits. In order to evaluate potential health benefits of organic foods, we used the well-characterized fruit fly Drosophila melanogaster as a model system. Fruit flies were raised on a diets consisting of extracts of either conventionally or organically raised produce (bananas, potatoes, raisins, soy beans). Flies were then subjected to a variety of tests designed to assess overall fly health. Flies raised on diets made from organically grown produce had greater fertility and longevity. On certain food sources, greater activity and greater stress resistance was additionally observed, suggesting that organic food bestows positive effects on fly health. Our data show that Drosophila can be used as a convenient model system to experimentally test potential health effects of dietary components. Using this system, we provide evidence that organically raised food may provide animals with tangible benefits to overall health.