Psycho-physiological Responses to Different Natural Sound Volume in City Acoustic Environments

• Main Authors: Chien-Fu Liao, 廖健富
• Other Authors: Chun-Yen Chang
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/61688265759620408319

碩士 === 國立臺灣大學 === 園藝暨景觀學系 === 102 === Abstract Acoustic environments reflect the construction of an environment and cause psycho-physiological feedback responses. The UN (2013) pointed out that more than 50% of the population of the world live in the cities. An urban green area natural sounds have positive benefits such as restorative experiences, positive emotional preferences, and sympathetic soothing; however, with economic development, noise pollution created by traffic has become the hallmark of city acoustic environments. Noise pollution has many negative effects that cause stress, anxiety, and has detrimental physiological effects as well as a masking effect on natural sounds. Sound levels (dB) are used as a metric to estimate sound impact. This study simulates the sidewalk acoustic environment between a city park and a road. Three experimental groups listened to a mixed 65 dB city sound with different natural sound levels (45dB/40dB/35dB). A pure city sound was used for the control group to identify the relationship between different masking levels and human psycho-physiological responses. This study used a notice-event model (short-term) and a perceived naturalness (long- term) was used to discriminate differences between independent variables. Participants were asked to evaluate the number of natural sound elements in proportion to levels of naturalness. In this study, we measured the psychological responses of 126 participants (National Taiwan University students) including restorative experiences, emotions (ZIPERS), preference, and physiological responses including heart rate (HR), electromyogram (EMG), and electroencephalogram-α (EEG–α). The results for the average score of the number of natural sound elements and perceived naturalness were low, which revealed that the acoustic environment was masked by city sounds. The findings for psychological responses (restorative experience, emotions, and preferences) among groups showed significant differences to further indicate that positive psychological benefits could be obtained from certain natural sound pressure levels. Moreover, the psychological responses also had positive correlations to the number of natural sound elements and naturalness. However, there were no significant differences between physiological responses and different levels of city acoustic environments. In addition, this study found that sound levels improve natural sound perception, decreased the masking of the acoustic environment by city sounds, and even showed improved psychological benefits. The results show that the promotion of the perception of natural sounds in city acoustic environments will induce psychological benefits. Additionally, if landscape practices, designers, and planners add natural sound elements by instruction and route by specifically using the perceptions of nature sound pressure levels, then city populations will likely experience better sound quality.