We have previously shown (see Part 1 and Part 2) how music can be a useful tool to drive performance. (The strains of Bach’s Goldberg variations are currently playing in the background. It’s blocking out the noise of distant traffic.) Whilst listening to music can be delightful, for some, music is a hindrance not a help. Noise is among the most frequent and annoying factors in many workplaces such as machine noise from close-by production areas, or the conversations of colleagues, or the sounds of traffic, or for those working from home, the sounds of children playing nearby…the list goes on and on. Noise is an omnipresent aspect of the auditory landscape that surrounds us. Unlike visual annoyances that you can avoid by shutting your eyes, it’s next to impossible not to hear something you don’t want to hear.
A study reported in the Lancet of a cross-national, cross-sectional study examining almost 3000 children aged 9–10 years from 89 schools in the Netherlands, Spain and the UK that were located near a major airport indicated that chronic exposure to aircraft noise may hinder cognitive development in children, particularly in reading comprehension. The study concluded that schools subjected to high levels of aircraft noise do not provide healthy educational environments. Yet, some airline passengers find the steady roar of an aircraft’s engine soporific. That's because it is the intermittent nature of a noisy environment that is problematic when it comes to productivity. For example, disruptive intermittent sound of aircraft taking off and landing degraded the children’s performance in reading comprehension.
So what’s to be done? Understanding noise is essential not only in fields like acoustics and sound engineering but also in psychology and health, where it impacts our daily experiences, productivity, and well-being.
Intriguingly, as some airline passengers find, sustained noise can sometimes be helpful, and these noises are colour coded. White, pink, and brown noise derive their name from the way these sounds are defined and their respective frequency distributions, often drawing parallels with the concept of colour in light and its characteristics.
White Noise
White noise is analogous to white light, which contains all visible wavelengths of light in equal intensity. Similarly, white noise encompasses a wide range of sound frequencies that are distributed evenly, meaning it contains equal energy across all frequencies within the audible spectrum. This balanced output makes it a consistent sound, resembling the static heard on a radio or television, or the whirring sound of a fan or air conditioner, or the sound of a vacuum cleaner.
Pink Noise
Pink noise is named in contrast to white noise and reflects a different frequency distribution. It contains equal energy across octaves, meaning its energy decreases with increasing frequency. This gives pink noise a deeper sound, much like the way the colour pink comprises a mix of all colors in varying intensities. The use of "pink" symbolizes its softer, more balanced qualities compared to the harsher "white." This deeper, richer sound is often compared to rainfall or ocean waves.
Brown Noise
Brown noise, also known as Brownian noise or red noise, derives its name from Brownian motion, which describes the random movement of particles in a fluid. In terms of sound, brown noise emphasizes lower frequencies even more than pink noise, producing a deep and rumbling quality. The use of "brown" reflects its lower tonal characteristics, similar to how darker colors often represent depth and richness. Brown noise has a sound reminiscent of distant thunder or a strong waterfall.
In a review of the potential use of white noise to improve occupational health, it was reported that white noise benefits working memory performance, helping to reduce the participants’ guess rate of tasks. Research on attention deficit hyperactivity disorder (ADHD) in children has shown an improvement in attention with background white noise. Researchers used cognitive experiments to discover how the different colour noises affected working efficiency and compared these results to a quiet environment. Noticeable improvements could be found in colour noises environments, compared with the quiet context. Listening to white noise can help with sleep cycles. It can reduce the delay in falling asleep.
Using white, pink or brown noise may prove to be a useful tool that masks other noises that may interfere with your productivity. If listening to music is not your thing, and yet you still find yourself annoyingly distracted by the sounds around you, then maybe it's time to try coloured noise. Just type white, pink or brown noise in your favourite music streaming service.
But, before you head off to your favourite streaming service to download your preferred choice of noise colour, it’s worth noting that there are several studies that have demonstrated no difference in performance between a colour noise environment and a quiet environment.
Overall, understanding these types of noise expands our appreciation of sound and its effects on our lives, allowing us to harness these auditory tools for improved mental clarity, relaxation, and sleep quality.
Dr Dominic Irvine & Professor Emeritus Simon Jobson