Thumyat Noe ’23

Nowadays, many people tend to spend most of their time indoors for work and leisure activities. Poor air quality and limited physical opportunities resulting from remaining indoors are often associated with a decrease in work efficiency and substandard physiological and psychological conditions. Hence, there is great interest among researchers on how indoor environments can be improved. Previous studies have suggested that indoor plants can promote human physical and psychological well-being. However, most of these studies utilized psychological questionnaires, which may not be reliable. Instead of psychological questionnaires to collect data, some researchers have proposed the use of electroencephalograms, which record electrical signals of the human brain at the scalp level. The brain waves recorded by electroencephalograms are used to represent emotional states; for instance, alpha waves reflect a calm and relaxed state while beta waves correspond to lucidity and quick thinking. Using electroencephalograms, some studies have found that artificial floral scents are able to reduce brain waves associated with negative emotions and memory impairment. However, these studies did not utilize scents from live plants.  The objective of this study conducted by researchers at Sichuan Agricultural University is to explore the effects of fragrant and non-fragrant Primula flowers on physiological and psychological states of female college students. Primula flowers were chosen because of their popularity in East Asia. 

50 college female students with normal olfactory functions participated in this study. Before exposing each participant to the Primula flower, physiological and psychological data of participants were obtained. Measurements of physiological data include pulse rate, blood pressure, and brain waves. Psychological data was collected verbally. Participants in the experimental group were then taken to the laboratory room, where they were asked to relax and breathe evenly in the presence of naturally fragrant Primula flowers. Participants in the control group were exposed to a different variant of Primula flowers that has no fragrance. On the next day, participants from the experimental group were exposed to control conditions while participants from the control group were exposed to experimental conditions. 

Differences of physiological data between the experimental and control groups before and after exposure to the Primula flowers were not significant. However, mean alpha wave and mean beta values were both higher in the experimental group after exposure to fragrant Primula flowers. Moreover, although both groups showed increase in relaxation after exposure to Primula flowers, the experimental group showed a significantly higher mean relaxation score. The experimental group also showed a higher positive scale score,  which suggests that fragrant Primula flowers induced a better emotional experience. Future studies could include male participants; in this study, only female college students were recruited since females are more sensitive towards smells. Overall, indoor plants are simple and inexpensive means to improve the quality of the indoor environment. In particular, aroma from these plants may be especially effective in promoting better physical and psychological health. 

Work(s) Cited: 

• S. Jiang, et al., Effect of Fragrant Primula Flowers on Physiology and Psychology in Female College Students: An Empirical Study. Frontiers in Psychology 12,  1-11 (2020). Doi: 10.3389/fpubh.2021.612725
• Image retrieved from: https://commons.wikimedia.org/wiki/File:House_plants.jpg