Can listening to white noise help you focus?

I use white noise to help me to sleep. And according to the results of a new study in Scientific Reports, I should be using it to help me to work, as well.

White noise contains equal amounts of all the sound frequencies that we can hear. Since at least 2007, research has suggested that it can boost the memory and attention levels of children diagnosed with ADHD. However, relatively little work has been done on neurotypical people — and the few studies that have been conducted have produced mixed results. So Mohamed Awada at the University of Southern California and colleagues set out to run a comprehensive investigation on the effects of white noise on cognition, using two different volumes of white noise and a broad battery of cognitive tests.

The participants were 39 young adults, who sat in a private office space to complete tests of sustained attention, working memory, creativity (they had to find a word that linked three others), and their ability to ignore distractions to focus on the requirements of a task (in this case, a Stroop test). They also had to type up a printed paragraph, and the researchers looked at how long it took them, and how many mistakes they made. Throughout, their skin conductance was measured, as an indicator of stress levels.

All the participants completed the tests three times: once without headphones and with background office noise, which was at a quiet 45 decibels (this produced baseline results, for comparison with the other conditions); once with headphones playing white noise at 45 decibels; and once with white noise at 65 decibels. (Though this volume in the last condition was much louder than in the two other conditions, it was still below a level that most people would find unpleasant).

The team found that the white noise played at 65dB improved performance on just one test — that of working memory. But it also increased stress, as shown by an increase in skin conductance.

However, 45dB of white noise improved sustained attention and creativity, and did not increase stress. (Also, while 45dB of white noise didn't improve performance on the typing test above baseline, it didn't worsen it, either — while 65dB of white noise did.)

This work suggests that 45dB of white noise can drive some cognitive benefits in neurotypical people. How? Perhaps by boosting background neural 'noise' in the brain.

A popular theory holds that a certain level of background noise in the central nervous system helps genuinely important neural signals to stand out, and be detected. The detection of important signals is clearly essential for good cognitive performance.

It's also thought that the neurotransmitter dopamine plays a role in this. Low levels of dopamine are thought to reduce neural noise, and so weaken cognitive performance, and research has linked ADHD to low dopamine levels. So researchers have tried exposing children with ADHD to fairly loud volumes (as high as 75 or even 85 decibels) of white noise, with the aim of counteracting the presumed dopamine-related deficit in neural noise — and reported cognitive benefits.

A neurotypical brain would be expected to already have the optimal level of background neural noise. But this new work suggests that perhaps even neurotypical brains can benefit from a little boost, from quiet white noise.

There is a lot of work still to be done, both to firm up the theories, and to explore the effects of white noise. As the researchers point out, it would be interesting to see work investigating the impact of other volumes, at points between 45 and 65 decibels, on these cognitive tests, and also other measures of performance, as required by different jobs. Some of the improvements seen in this study were also very small, so it's unclear whether white noise really can make a real-world difference to the cognitive performance of neurotypical people.

Still, adding quiet white noise to an office environment would be simple and cheap. Certainly, the researchers hope that ultimately white noise might be used as a performance booster, perhaps with the volume being altered according to the task at hand. "These results lay the foundation for the integration of white noise into office workspaces as a tool to enhance office workers' performance," they conclude.