4.2. Effects of Olfactory, Visual and Olfactory–Visual Stimuli on the Central Nervous System
All three types of stimulation affected the central nervous system, which can be seen from the ANOVA results for the α and β brainwave amplitudes. The ANOVA results suggest that during exposure to the olfactory, visual and olfactory–visual stimulus modes, the subjects’ alpha and beta brainwave amplitudes exhibited significant increases compared with the control group. In addition, the visual stimulation group exhibited significantly higher increases in these amplitudes than the olfactory stimulation group, suggesting that compared with single-smell stimulation, the degree of influence of visual stimulation on the central nervous system was more obvious. This finding confirms the long-held belief that the visual system is the main method humans use to receive information from the external environment [Moreover, Fang M found that after subjects smelled the aroma of Osmanthus distillation extraction, their alpha wave amplitudes reduced significantly [