A Shield against Distraction from Environmental Noise

Abstract: Working in noisy environments can be detrimental to cognitive performance. In order to perform well people have to find a way to attenuate distraction. This thesis aimed to study the balance between distractibility and task demands in the context of office-related tasks as a means by which to better understand how people in the work environment are influenced by environmental noise.In Report 1, 2 and 3 higher focal-task difficulty was achieved by manipulating the readability of the text that participants were asked to read (i.e. either displaying the text in hard-to-read font or by masking it with static visual noise). The results of Report 1 and Report 2 showed that background speech impaired performance on proofreading and memory for written stories respectively compared to silence, but only when the focaltask difficulty was low, not when it was high.In Report 3 it was shown that background speech, road traffic noise, and aircraft noise impaired performance on text memory compared to silence, but again, only when focal-task difficulty was low.In Report 4 it was tested whether higher cognitive load on the focal task would reduce peripheral processing of a to-be-ignored background story. The results of Report 4 showed that participants in the low-load condition recalled more of the information conveyed in the to-be-ignored background story compared to participants in the high-load condition. It was also investigated whether individual differences in working memory capacity (WMC) would influence participants’ memory for written stories (Report 2) and incidental memory of the to-background story (Report 4) differently depending on task demand.The results showed that individuals scoring high on the WMC-test were less distracted by background speech in the easy-to-read font condition (Report 2), and recalled less of the information in the to-be-ignored background story in the low-cognitive load condition (Report 4) compared to individuals that scored lower on the WMC-test. These relationships were not found in the hard-to-read font condition in Report 2, or in the high-cognitive load condition in Report 4. Taken together, these results indicate that higher focal-task difficulty can shield against the detrimental effect environmental noise on performance on office-related tasks. Moreover, it shows that higher focal-task difficulty can help individuals with low-WMC to reach a level of performance that is similar to that of high-capacity individuals.