“…For this reason, we included an assessment of trait impulsivity, a well-established psychological measure of one's tendency to behave with little forethought, reflection, or consideration of the consequences (Mayhew and Powell 2014 ). Animal and human models suggest that this measure is predictive of future risk of developing mental-health issues including addictive disorders (McChargue et al 2011 , Kunst and Van Wilsem 2013 , Velázquez-Sánchez et al 2014 , Sanchez-Roige et al 2014 , Dalley and Robbins 2017 ), attention-deficit hyperactivity disorder (Ahmad and Hinshaw 2017 , Martel et al 2017 ), antisocial personality disorder (González et al 2016 , Martel et al 2017 ), and bipolar disorder (Tu et al 2017 ). We used the data to test three related hypotheses: (1) exposure to natural features, including trees, the sky, birdsong, and water, would be associated with higher levels of momentary mental well-being; (2) these effects would still be evident in subsequent assessments, in which people are no longer exposed to trees, the sky, birdsong, and water, indicating time-lasting benefits; (3) these effects would be more evident in people with higher trait impulsivity, who are thought to carry greater vulnerability to mental-health issues, than those with lower trait impulsivity (Dalley and Robbins 2017 ).…”