Effect of Faint Road Traffic Noise Mixed in Birdsong on the Perceived Restorativeness and Listeners’ Physiological Response: An Exploratory Study

Abstract

Many studies have reported that natural sounds (e.g., birdsong) are more restorative than urban noise. These studies have used physiological and psychological indicators, such as the skin conductance level (SCL) and the Perceived Restorativeness Scale (PRS), to evaluate the restorative effect of natural sounds. However, the effect of faint background noise mixed with birdsong on the restorativeness of birdsong has not been described yet. In the current experiment, we examined whether traffic noise affects the perceived restorativeness and the physiological restorativeness of birdsong in a low-stress condition using the SCL and the PRS. The scores of the PRS showed that birdsong significantly increased the perceived restorativeness of the place regardless of the car noise, but no significant difference was found between these two birdsongs. In contrast, physiologically, the birdsong without car noise decreased the participants’ SCL significantly more than the birdsong with car noise did. These results indicate that the SCL would be useful to detect the effect of background noise on natural sound when the noise is too low to affect the perceived restorativeness. This study highlights the importance of measuring the SCL besides assessing perceived restorativeness to describe the characteristics of restorative natural sound in future research.

RETRACTED: The Effects of Soundscapes in Relieving Stress in an Urban Park

“…Soundscapes are one of the main elements of restorative landscape design and have an important recreational value, and from a health perspective sound perception can be used as an enhancement tool for the human experience [18]. It has been shown that natural sounds such as birdsong are preferred to relieve stress, reduce anxiety and agitation and contribute to emotional recovery, and their restorative effects are supported by physiological indicators such as skin conductance level, heart rate and heart rate variability [19][20][21][22].…”

Urban green space soundscapes and their perceived restorativeness

“…Importantly, by assessing the combined effect of beneficial and non-beneficial sounds, we could demonstrate that increasing perceptions of traffic volume undermined the beneficial effects of bird pleasantness. Recently, Suko et al (2019) found that faint levels of traffic noise among birdsongs resulted in significantly less physiological restoration than birdsongs without traffic noise. However, with respect to perceived restorativeness, the same study did not find any significant differences with or without the traffic noise amongst bird songs.…”

“…Anthropogenic sounds such as traffic noise may constrain restoration benefits associated with bird sounds. Although Suko et al (2019) found that bird songs with and without low traffic noise displayed no significant difference between perceived restorativeness scores, they did not examine the effect of varying levels of traffic noise. We hypothesise that as traffic noise is more strongly perceived among bird sounds, the beneficial effects of these soundscapes will be increasingly constrained.…”

“…The mean score was taken as the bird activity score (A. Truskinger, personal communication, May 5, 2019). An indicator of traffic sound was derived by measuring the maximum A-weighted volume (dB) in the low level frequency of 25-500 Hz (similarly used by Suko et al, 2019) (Table S1). In the decibel scale, a 3db increase represents twice the sound pressure energy (sound intensity level), while in psychoacoustic terms, an approximately 10 db increase equates to twice the perceived loudness of a sound (Vic Roads, 2013).…”

“…In particular, we are interested in the interaction of positive and negative effects of soundscapes, that is, the extent to which vehicle traffic noise may diminish the restorative benefits of bird sounds. Currently, research in this area is somewhat unclear, with Suko et al (2019) finding faint traffic noise mixed with bird songs, had a physiological impact but no effect on psychological restoration. As urbanisation continues to place pressure on existing urban and peri-urban green spaces (Fuller & Gaston, 2009), maintaining or creating diverse ecosystems within urban or peri-urban parks can constitute a critical investment in improving the quality of life of citizens (Dean et al, 2011).…”