Abstract:

Objective: This paper aims to explore the effects of garden plant smellscape which is odor and the multi-dimensional interactive perception of garden environment caused by smell on human health, by deeply analyzing the difference of effects of olfactory, visual and olfactory-visual interactive stimulation related to garden plants on human physiological and psychological responses, so as to provide theoretical basis and new ideas for garden plant smellscape design. Method: In a randomized controlled study, the odor of four common garden plants in northwest China and the panoramic images of their corresponding landscape were used as stimulus materials, and 312 college students were selected to be subjected the stimuli. NeuroSky brainwave tester, OMRON upper arm electronic sphygmomanometer and VISHEEW multiparameter biofeedback instrument were used to measure physiological indicators of the students in the virtual simulation laboratory. The emotions induced by smellscape and the perception of the overall environment were evaluated by state anxiety scale (S-AI) and smellscape emotion scale (SD). For physiological index data, One-way ANOVA was used to screen out indicators with significant differences. Spearman correlation analysis was used to test the correlation between each experimental stimulus factor and these indicators, and then multiple linear regression method was used to analyze the relationship between each indicator and different stimulus factors. Finally, one-way ANOVA and LSD postmortem test were conducted for the screened index data. For psychological indicators, ANOVA and LSD postmortem test were performed on the S-AI scale data, and Wilcoxon rank sum test was performed on the mean score data of each adjective option in SD. Result: The results of physiological measurement showed that: 1) In the olfactory stimulation group, before and after stimulation, the amplitude of α, β brainwave and skin electroencephalogram (SC) decreased significantly in the grass, Pinus tabuliformis and Rosa chinensis groups, and the amplitude of α and β brainwave decreased the most in the pine scent group (Δα=?24%, Δβ=?19.8%). The SC value decreased the most after smellingR. chinensis (ΔSC=?13.3%). 2) The amplitude of α, β brainwave and SC were significantly increased by visual stimulation in most experimental groups. The amplitude of α brainwave was increased the most by viewingR. chinensis (Δα=76.3%), and the amplitude of β brainwave and SC were increased the most by viewing Osmanthus fragrans (Δβ=92.7%, ΔSC=90.8%). 3) The amplitude of α and β brainwave induced by olfactory and visual interaction increased significantly in R. chinensis and O. fragrans, and SC induced by olfactory and visual interaction increased significantly in the 4 plant smellscape. The amplitude of α and β brainwave increased the most in R. chinensis olfactory and visual interaction group (Δα=29.7%, Δβ=39.6%). O. fragrans olfactory and visual interaction group (ΔSC=22.6%) had the highest increase in SC. The results of psychological measurement showed that olfactory-visual interaction was more likely to enhance participants' positive psychological perception of the environment, such as ‘attraction’, ‘uniqueness’ and ‘coordination’, than olfactory stimuli alone. Conclusion: The olfactory and visual interaction associated with garden plant smellscape can make people relax physically and psychologically to a certain extent. Olfactory and visual interaction shows a compromise effect in central nervous system and an accumulative effect in autonomic nervous system, and can generally enhance people's positive psychological perception of the environment. In the future, garden plant smellscape design should start from the perspective of multi-dimensional perception interaction and give full play to its health effect.

Key words: garden plant, smellscape, olfactory and visual interactive stimulus, central nervous system, autonomic nervous system, psychological effect