Using Natural Environments to Reduce Craving: Affective and Cognitive Mechanisms

Although chronic and acute exposure to natural environments has been linked to a range of health and wellbeing benefits (Hartig et al., 2014; WHO, 2016), there has been little work exploring the links between natural environments and potentially health-damaging behaviours. The aim of the current research is to investigate these issues, particularly whether living near and/or visiting nature can reduce tonic (background) and phasic (cue-provoked) cravings (Hitsman et al., 2013) and thus whether nature exposure can help individuals better manage cessation attempts. Several strands of evidence support further study of these issues. First, even passive exposure to natural environments (e.g. sitting on a bench, Biel & Hanes, 2013) has been shown to significantly reduce negative affect and stress (McMahan & Estes, 2015), two psychological constructs which are positively associated with the number and strength of intrusions and cravings (Kavanagh, May, & Andrade, 2009). Moreover, short bouts of physical activity are related to reductions in cigarette craving, via a mood related pathway (Haasova et al., 2013), and many encounters with nature also involve physical activity (White et al., 2016). This suggests that the benefits for affective regulation and stress reduction, for example, of a walk in the park, may be cumulative. Second, exposure to natural environments is associated with improvements in directed attention (Ohly et al., 2016), but not visuospatial memory (Bratman et al., 2015). As craving can also be reduced through competing visuospatial tasks (May et al., 2010), natural environments could reduce craving by visuospatial interference, whilst simultaneously improving the cognitive resources required for self-regulation and behavioural change. Notably, nature exposure has been associated with reductions in rumination and impulsivity (Bratman et al., 2015; Kuo & Taylor, 2004), as well as improvements in self-control (Jenkin et al., 2017) and delayed gratification (Kuo, Taylor & Sullivan 2002). Thus, natural environments may reduce craving through a complex interplay of affective and cognitive pathways. Third, recent qualitative studies with individuals undergoing drug and alcohol rehabilitation report reduced rumination and craving when individuals were on a sail training trip vs. in a residential support setting (White et al., 2016) or when visiting a beach vs. a town centre (Turner et al., 2017). As well as providing preliminary support for the central hypothesis of the current proposal, both studies highlight that aquatic natural environments may be particularly beneficial for stress reduction (Völker & Kistemann, 2011) and thus possibly craving. Further work is needed to systematically explore both tonic and phasic craving using standardised tools and settings. Finally, natural environments have unintentionally been a confounding factor within several key studies examining the effect of imagery upon craving (e.g. beach imagery Versland & Rosenberg, 2007). Further work is needed, using nature and non-nature controls, to establish whether the observed effects are attributable to visuospatial interference as intended, or the nature exposure confound.
The current proposal is an extension of an ongoing MSc project exploring the relationships between natural environments, affect and tonic craving. The proposed PhD aims to examine: a) the relationship between residential exposure to natural environments and tonic craving; b) the effects of specific nature exposures on phasic craving; and c) the potential cognitive and affective mechanisms behind any effects. Synthesising and extending two fields of research, this project has practical applications to health and behavioural change.