Effect of combined noise sources on cognitive performance and perceived disturbance.

Abstract

An experiment was conducted to investigate the differences in cognitive performance and perceptions under road traffic noise and construction noise combined with road traffic noise. Under the conditions with individual noise and combined noise sources, an episodic memory task and semantic task were carried out in the laboratory. The subjects were asked to recall the presented words after the exposure to noises (episodic memory task) and to select the target word when the five words, including the target word and other words, were presented simultaneously (semantic memory task). Subjects also rated perceived annoyance and disturbance to the noise exposure during the experiment. The result showed that the percentage of correct answer significantly decreased with an increase in construction noise in an episodic memory task. In contrast, the semantic memory task was not impaired by the level of construction noise level. This indicates that only the retrieval task with a process of generating the internal cues was affected by the level of combined noise sources. And it was also found that the perceptions of combined noise sources were highly correlated with the result of the episodic memory task.