A dose of nature: Two three-level meta-analyses of the beneficial effects of exposure to nature on children's self-regulation

There is growing evidence that exposure to nature, as opposed to a built environment, is associated with better health. Specifically in children, more exposure to nature seems to be associated with better cognitive, affective, and behavioral self-regulation. Because studies are scattered over different scientific disciplines, it is difficult to create a coherent overview of empirical findings. We therefore conducted two meta-analyses on the effect of exposure to nature on self-regulation of schoolchildren (Mage = 7.84 years; SD = 2.46). Our 3-level meta-analyses showed small, but significant positive overall associations of nature with self-regulation in both correlational (15 studies, r = .10; p < .001) and (quasi-) experimental (16 studies, d = .15; p < .01) studies. Moderation analyses revealed no differential associations based on most sample or study characteristics. However, in correlational studies the type of instrument used to measure exposure to nature (index score of nature vs. parent-reported exposure) significantly moderated the association between nature and self-regulation. Stronger associations were found when exposure to nature was assessed via parent-reports than via an index such as by a normalized difference vegetation index (NDVI). Our findings suggest that nature may be a promising tool in stimulating children's self-regulation, and possibly preventing child psychopathology. However, our overview also shows that we are in need of more rigorous experimental studies, using theoretically based conceptualizations of nature, and validated measures of nature and its putative outcomes.