Physiological and psychological responses to olfactory simulation by Taiwania (Taiwania cryptomerioides) essential oil and the influence of cognitive bias

Taiwania (Taiwania cryptomerioides) is a valuable raw material in the wood products industry in Taiwan. An empirical study of the physiological and psychological effects of smelling Taiwania contributes to an understanding of the properties of interior wood that could potentially promote the use of wood materials in a healthy living environment. Prior studies have indicated that pre-knowledge of odors can cause cognitive bias and different responses in subjects. Designed to disclose the therapeutic effects of Taiwania's scent and its extension to environmental health promotions, this study aimed to (1) investigate its effects on human health responses by stimulating olfaction, and (2) explore the role of cognitive bias in exposure to the scent of Taiwania. The results showed Taiwania's volatiles had a relaxation effect in reducing the heart rates of participants. Some negative mood states, such as confusion, fatigue, and depression were suppressed. Regarding sensory perceptions, participants reported Taiwania's scent induced greater affective scores of stimulation, excitement, firmness, distinctiveness, activity, and denseness, but a lower feeling of pleasantness. There were significant effects of positive cognitive bias on reducing the anger-hostility feeling of participants, but no effects on physiological responses. Moreover, the positive information bias alleviated the unpleasantness toward the smell.