In the simplest of terms, white noise is sound that can be used to cover up background sounds. Because of its ability to drown out potentially distracting sounds, white noise is often recommended as a sleep and study aid. For example, people who find it hard to fall asleep without a fan running in the bedroom may not be responding to the fan's cooling breeze, but to its soothing sound. However, while it has been found effective in helping people sleep and learn in some cases, white noise can have some negative effects, especially when used with newborns.
Key Takeaways: White Noise
- White noise is the combination of all approximately 20,000 sound frequencies people are capable of hearing, ranging from about 20 to about 20,000 Hz.
- Most people describe white noise as a hissing sound, like the sound of the letters “sh” in the word “hush.”
- White noise has been found effective in helping people fall asleep, as well as study and learn.
White Noise Definition
Science defines white noise as the combination all of the audible sound frequencies. Research has shown that people with normal hearing can hear sound frequencies ranging from 20 to 20,000 Hz. In other words, white noise can be thought of being like the sound of about 20,000 different tones all playing at once. The actual sound of white noise is typically described as hissing sound, similar to the sound of the letters “sh” in the word “hush.”
The adjective “white” was chosen to describe this ultimate combination of sounds because of the similarity of white noise to the qualities of white light, the scientific description of the combination of all colors of the visible light spectrum.
As a combination of all audible frequencies, white noise can be used mask other potentially distracting sounds. For example, turning on a fan might help drown out the voices from a next-door neighbor's loud party. In this sense, the droning sound of the fan is similar to white noise. But how does white noise mask other noises?
In normal conversation, for example, people can usually pick out and understand individual voices when groups of three or four people are all speaking at the same time. However, when large groups of people are talking simultaneously, the likelihood of being able to hear any single voice is greatly reduced. In this nature, the sound of say 1,000 people talking at once is similar to white noise.
White Noise for Studying
Since most people who are distracted find it hard to focus, teachers urge students to study in quiet rooms. But because they find studying boring, some people say that sounds like music or television actually help them concentrate. However, since such easily-distinguished sound can become distracting, some educators and psychologists suggest white noise as an alternative study aid.
While the use of white noise as a sleep aid has been around since the early 1960s, the theory that it might also help people learn is relatively new.
Research conducted in 2014 at the University of Hamburg-Eppendorf Medical Center and published in the Journal of Cognitive Neuroscience, found a positive link between white noise and people learning mathematics, and the short-term memory of children with attention-deficit hyperactivity disorder (ADHD).
Other research, however, indicates that the effects of background noise on learners can depend on their individual personalities. For example, a 2010 study done at University College in London found that both white noise-like sounds and music actually impaired the comprehension, memory and learning ability of introverts.
In other words, the effectiveness of white noise or other background sounds as a study aid remains a case of personal experience rather than well-established scientific research.
White Noise for Sleep
While it may seem illogical, the idea that noise can help people fall asleep is well established. Devices that produce white noise have been popular sleep aids for years. Many people find it hard, if not impossible, to get to sleep without their white noise machine. To them, total silence is a distraction.
Since years of extensive research have shown that chronic sleeplessness can cause brain damage, doctors often recommend white noise devices for treating sleep deprivation. In addition, white noise is sometimes used as an alternative therapy in treating tinnitus, a constant ringing in the ear that can disrupt sleep. But how does white noise help people get to sleep?
Beneficial to our own survival, our sense of hearing still works while we are asleep. Science suggests that rather than the background noise itself, it is sudden changes in background noise that jars us from sleep. By creating a sound masking effect, white noise blocks sudden changes in sound helping people fall asleep and light sleepers remain asleep.
In what has become the “sleep industry,” the term “white noise” is used as a generic description for any background noise that is constant and unchanging. Other relaxing or comforting sounds available on today's so-called “sleep machines” include soothing sounds from nature, like gentle rain, ocean surf, distant thunder, and crickets chirping. Many people find these sounds to be more effective as sleep aids than the “sh” sound of pure white noise.
White Noise and Helping Babies Sleep
White noise is often recommended as helpful in getting babies to fall asleep and establish regular sleep patterns. A groundbreaking study conducted in 1990 at the Royal College of Physicians of Ireland found that 32 of 40 newborns studied (80%) were able to fall asleep after just five minutes of listening to white noise.
However, the American Academy of Pediatrics warns that there can be pros and cons of using white noise machines with infants.
The Pros of White Noise for Babies
- Some babies do fall asleep faster with white noise in the background.
- White noise can help drown out household noises common during nap times.
- Some white noise machines comfort and relax newborns by producing a sound mimicking their mother's heartbeat.
The Cons of White Noise for Babies
- White noise machines do not help all babies fall asleep and may even prevent some from sleeping.
- The maximum volume settings for white noise machines may exceed recommended noise limits for babies.
- Newborns can become “addicted” to white noise, becoming unable to sleep without it.
While they may be tempted to try anything to get baby to sleep, parents should talk to their pediatrician before resorting to white noise machines.
What About Television and Sleep?
Either accidentally or on purpose, many people fall asleep while watching television. Some people even use a TV as a type of white noise machine to help them get to sleep. However, research has shown that TV-sleep is not always healthy sleep. Many test subjects who had spent a full seven to nine hours sleeping with a TV on in the room reported still feeling drowsy or not fully rested in the morning.
Unlike white noise, the volume and tone of the TV change constantly, and since the sense of hearing continues to function during sleep, these changes can disturb sleep. Some people even wake up if the TV is turned off. In addition, the constantly changing colors and brightness of the TV picture can interfere with sleep.
Essentially, researchers say that while they are rarely consciously aware of it, parts of peoples' brains continue to “watch” the TV even while they sleep.
For a healthy, restful night's sleep, health care experts recommend that both the sound and lighting levels in the room remain consistent throughout the sleep period.
Sources and Further Reference
- "Sensitivity of Human Ear." Hyper Physics.
- Rausch, Vanessa H., Bauch, Eva M. (2014). "White Noise Improves Learning by Modulating Activity in Dopaminergic Midbrain Regions and Right Superior Temporal Sulcus." Journal of Cognitive Neuroscience.
- Furnham, Adrian & Strbac, Lisa. (2010) "Music is as distracting as noise: The differential distraction of background music and noise on the cognitive test performance of introverts and extraverts." University College, London.
- Horowitz, Seth. (2012) "The Universal Sense: How Hearing Shapes the Mind." Bloombsbury USA. ISBN-10: 1608198839.
- Spencer, J.A., Moran, D.J., Lee A, and Talbert, D. (1990) "White noise and sleep induction." Royal College of Physicians of Ireland. Archives of Disease in Childhood.
- "Can Infant Sleep Machines Be Hazardous to Babies' Ears?" (2014). American Academy or Pediatrics.
- Cespedes, Elizabeth M., SM. (2014). "Television Viewing, Bedroom Television, and Sleep Duration from Infancy to Mid-Childhood." Pediatrics.
- "A good night's sleep." Kaiser Permanente.