Plants used in the greening designs.

Impression on biophilic designs influences the effects of indoor greening. The current study aimed to investigate the effects of different biophilic designs in office rooms on the psychological and physiological responses and the cognitive performance of office workers. Indoor greening rooms with Japanese and tropical designs were used along with the green-free (control) design in this study. The heart rate variability of the participants was not affected by green designs. However, there was improvement in impressions on tropical and Japanese designs in office rooms. In particular, the Japanese design was more effective in decreasing negative emotions than the tropical design. The electroencephalography during 5-min exposure to the greening designs showed limited frequency bands and regions of interest affected by the greenery design. Taken together with the psychological data, indoor greening with the tropical design promoted positive mood states. Meanwhile, indoor greening in the Japanese design, inhibited negative mood states. However, there were no significant differences between the two designs in terms of cognitive task performance. Hence, indoor greening increases neural efficiency during cognitive tasks.