Improving informational-attentional masking of water sound on traffic noise by spatial variation settings: An in situ study with brain activity measurements

According with soundscape strategies to improve the perception of the sound environment, laboratory studies have proven that introducing water sounds into urban spaces can be both an effective strategy for the informational-attentional masking of road traffic noise, and restorativeness creation. To extend previous laboratory findings and test the effectiveness and applicability of different spatial variations of water sounds in urban parks, a sound installation was prepared, and an experiment was conducted. Three different position-varied water-sound sequences were augmented into an existing University campus green park through surround sound design method with four Bluetooth loudspeakers. The mental effects and attention process were assessed by analyzing the EEG signals including aperiodic, oscillatory components and sensor-level functional connectivity, along with psychological scales. The water sounds played in-situ, brought more visual processing related to spatial attention and stimulus-driven salience. And the changes in the alpha band and the related theta/alpha ratio among four conditions showed more relaxation state induced by the introduction of water sounds, consistent with the positive effects on emotion saliency and perceived restorativeness. Moreover, different spatial variations of water sounds, especially for the two-position switching setting, modulated the activity of the attentional network related to the restoration process via the alpha-theta synchronization.