White noise is often confused or conflated with sound masking. However, it has uses of its own. Primarily in research environments. White noise is a sound where all audible frequencies occur in equal measures. Unlike in sound masking there is no shaping. This is useful for research, including for researchers in this next blog in our Acoustics in the Sun series. The paper is titled The effect of white noise and “coloured” noise on cognition and sleep, by local researcher Wayne Wilson.
The presentation
Setting aside the paper for a moment, the author’s presentation captured my imagination right away. It covered his ongoing research, which includes experimenting on grad students—always fun. At the time, he was attempting to determine whether high levels of white noise in headphones will aid or hinder the recall of his students. I was interested to learn he’d set the sound levels way above what I would consider to be comfortable—70dBA. I’m hoping Wilson will make an appearance at Acoustics 2025 with those findings!
The premise
As for the paper itself, I had high hopes. This is because I’m a fan of sleep and a high profile name in sleep research, Phyllis Zee. Unfortunately, it was a bit of a victim to its own parameters. It only reviewed data from the past five years. This excluded papers like Northwestern and Zee’s breakthrough Acoustic Enhancement of Sleep Slow Oscillations and Concomitant Memory Improvement in Older Adults, which show evidence of pink noise benefiting specific cohorts. You can read more about that here.
That said, the paper sought to review the scientific literature to determine whether there was evidence to recommend white or coloured noise for sleep. In effect reviewing reviews, which gave a comprehensive and diverse dataset.
The findings
The research Wilson examined was necessarily broad, and as a result somewhat contradictory. For example, noise levels set for experiments ranged from 20dB to 93dB with different weightings (A,C,Z). The participants ranged from infants to adults, and everyone in between. It’s hardly surprising Wilson found no clear conclusions. However, it is worth a read just to see the kind of research that’s been undertaken.
You can find the full paper here.