The role of paying attention to sounds in soundscape perception.

Ghent University, Gent, Belgium, .
The Journal of the Acoustical Society of America (Impact Factor: 1.65). 04/2012; 131(4):3382. DOI: 10.1121/1.4708755
Source: PubMed

ABSTRACT It has been stated frequently that the soundscape as perceived and appraised by the user of a space, extends beyond the physical stimulus. We argue that, when introducing to human-factor in analyzing a sonic environment, the sounds that people hear play an important role. This holds in particular for rather quiet and infrequent disturbance of park soundscapes. Auditory attention mechanisms are essential in the process. Attention can be drawn by saliency elements such as changes in time and frequency, but it can also be outward oriented and voluntary. These mechanisms could explain the special role of natural sounds in distracting attention from mechanical background hum in a park environment. These theoretical concepts have now been implemented in measuring equipment that allows estimating how often particular sounds will be heard by a human listener. The methodology includes biologically inspired feature extraction, learning based on co-occurrence of features and saliency, attention focusing, and inhibition of return. Extension to binaural measurements increasing the unmasking effect is also discussed.

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    ABSTRACT: This work analyzed the perceptual attributes of natural dynamic audiovisual scenes in two consec-utive experiments. First, we presented 30 naive participants with 19 natural scenes depicting urban environments reproduced with an immersive audiovisual display utilizing surrounding visual projec-tions and spatial audio reproduction. The aim was to assess the perceptual dimensionality of natural scenes, and to identify significant perceptual attributes by means of a similarity categorization task and an interview. A two-dimensional perceptual map of the stimulus scenes and perceptual attributes was formed, and the exploratory results show the amount of movement and perceived noisiness of the scene to be the most important perceptual attributes in naturalistically reproduced real-world urban environments. We found the scene gist properties openness and expansion to remain as important factors in scenes with no salient auditory or visual events. Our second experiment was organized with 23 naive participants to assess the modality contributions in three salient perceptual attributes through pairwise unimodal and bimodal scene discrimination tasks with short (< 500 ms) natural scene exposures. The chosen attributes were movement, noisiness and openness. Both visual and auditory information were found to affect scene discrimination in all the attributes, and bimodal discrimination was found superior to either of the unimodal accuracies in most cases. We propose that the study of natural scene perception should move forward to understand better the processes behind multimodal scene processing in real-world environments. The stimulus scenes are available as a public database of spherical video recordings and A-format audio recordings.
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