Differentiating mental health promotion effects of various bluespaces: An electroencephalography study

A growing body of literature suggests that visual contact with bluespace may benefit people's mental health. However, whether these benefits vary with the type of bluespace and length of contact duration is unclear. We addressed this critical knowledge gap by conducting a photograph-based experimental study to examine individual mental responses (n = 30) to three types of bluespace (Falling, Flowing, and Static bluespaces) and one control condition (Streetspaces). The participants were assigned to view four conditions in a random sequence in a laboratory. The effect of each condition on mental health was primarily measured through a portable electroencephalogram (EEG) device that continuously recorded brainwaves throughout each contact. We then administered the Restorative Components Scale (RCS) questionnaire as a secondary measure to the participants, who reported psychological states immediately after each contact. We have four main findings. First, visual contact with all three bluespaces yielded significantly greater mental health promotion effects than visual contact with streetspace. Second, the promotion effects of bluespaces varied, and the Falling bluespace was found to be the most beneficial type, as contact with it yielded the highest level of alpha brainwaves, the lowest level of beta brainwaves, and the highest score on the RCS questionnaire. Third, the type of environment appears to be the main factor, and contact duration appears to be the minor factor in explaining the differences in the mental health promotion effects. Finally, a 3-min contact with bluespaces is sufficient to promote mental health. We provide suggestions for future research into bluespaces and how bluespaces can be used to promote urban residents' mental health and well-being.