Nature Exposure Improves Inhibitory Control Efficiency: Evidence from the N2 ERP Component and Theta/Beta Ratio During Conflict Monitoring

Viewing natural environments often produces improved cognitive performance relative to urban or control environments. According to Attention Restoration Theory, this is largely attributable to replenishment/recovery of an inhibitory cognitive resource. Despite widespread use of conflict monitoring tasks in attention restoration research, modulation of the conflict-related N2 ERP component has received limited investigation. This study investigated the neural correlates of attention after exposure to natural and urban environments, along with measures of heart rate variability, self-reported state measures, and their interaction with trait nature relatedness. Participants (n=43) were randomly allocated to experience a 13-minute audio-visual recording of either natural or urban scenes. EEG and ECG were recorded during a resting period, cognitive fatigue induction (Stroop task), and pre- and post-exposure completion of a Flanker Go/No-Go Task. Bayesian hierarchical modelling was used to estimate any nature benefits in cognitive performance and corresponding neural resources, as indexed by frontal N2 amplitude and Theta/Beta Ratio (TBR). Changes in alpha power, heart rate variability (LF/HF ratio), self-reported affect, perceived restorativeness, and state mindfulness were also reported. Results showed that state mindfulness, positive affect, and perceived restorativeness were differentially benefited by nature relative to urban exposure. While experiencing the nature intervention, mean alpha power was higher and LF/HF was lower compared to the urban intervention. Response time and accuracy reliably improved more after nature exposure, relative to urban exposure. Performance benefits corresponded with decreased N2 amplitude in the nature group only, and increased TBR in the urban group only. These results replicate a previous association between nature exposure and reduced N2 amplitude, suggestive of more efficient inhibitory control processing. Higher nature relatedness enhanced nature benefits for most state-based, but not cognitive outcomes. Findings are relevant to competing theories in the field, as well as therapeutic programs for clinical and non-clinical groups with attentional difficulties.