2.2. Experimental Design
All the data collected in this study were measured in the Virtual Simulation Room of the Landscape Architecture and Art College at Northwest A&F University, and all the participants were exposed to the same environmental conditions. The experiment was carried out in a room with white walls and ceilings, and the interior space was 4 m (long) × 3 m (wide) × 3.1 m (high). In order to prevent the mood of the subjects from being affected by weather and light, the indoor environment was kept the same: ambient light was 300 lx, ambient sound was not higher than 45 ± 5 dB, temperature was 25 ± 2 °C and relative humidity was 55 ± 5%. The physiological test instruments were placed behind the chair the subjects were sitting on, and on the opposite side of the chair was a white wall to avoid unnecessary visual influence (A single-blind test was performed using a randomized and crossover design, and physiological reactions, including autonomic nervous system indicators and changes in the central nervous system, were measured. Participants were randomly assigned to different processing sequences (olfactory, visual, olfactory–visual stimulus sequences and the control group). In each group of experiments, subjects were randomly subjected to stimuli, and the flows of other steps were the same except for different stimulus types set in the intervention stage of the experiment, as shown in 