Foliage colors improve relaxation and emotional status of university students from different countries

Liu Kexiu; Mohamed Elsadek; Binyi Liu; Eijiro Fujii

doi:10.1016/j.heliyon.2021.e06131

Foliage colors improve relaxation and emotional status of university students from different countries

Heliyon. 2021 Jan 31;7(1):e06131. doi: 10.1016/j.heliyon.2021.e06131. eCollection 2021 Jan.

Authors

Liu Kexiu¹, Mohamed Elsadek^{2

3}, Binyi Liu², Eijiro Fujii⁴

Affiliations

¹ The 6th Architectural Design and Research Institute, China United Engineering Corporation Limited, China.
² Department of Landscape Architecture, College of Architecture and Urban Planning, Tongji University, China.
³ Department of Horticulture, Faculty of Agriculture, Suez Canal University, Egypt.
⁴ Graduate School of Horticulture, Chiba University, 648 Matsudo Matsudo-shi Chiba, 271-8510, Japan.

Abstract

The therapeutic advantages of seeing plants have gained increasing consideration in stressful modern societies, however, evidence-based studies on how physiological and emotional states of individuals from different nationalities change when seeing different foliage colors are limited. The study was conducted to explore the physiological and psychological advantages of foliage colors as visual stimuli. The experiment included 40 men from two nations (age: 21.34 ± 3.50 years) and was carried out using five foliage colors including green, light green, green-yellow, green-red and green-white. Participants were exposed to each color for 2 min, when seeing the foliage colors, eye movements and oxy-Hb concentrations were continuously measured. Subjective evaluations of emotions were performed utilizing a semantic differential questionnaire. A significant decrease in oxy-Hb concentration in the frontal lobe was associated with the viewing of green and green-white plants by the Japanese participants and with viewing light green and green-yellow by the Egyptian participants. Participants spent higher fixation numbers and longer durations on these colors. The findings indicate that viewing of these plant colors was positively associated with physiological relaxation. Furthermore, these colors were associated with more positive feelings, such as calmness, comfort and naturalness. Therefore, the presence of these colors in spaces may have positive impacts on relaxation and emotional status.

Keywords: Brain activity; Color perception; Cultural difference; Emotional status; Eye movement; Landscape design; Near-infrared spectroscopy; Relaxation.