First studied in animals, stochastic resonance experiments suggest "sensory signals can be enhanced by noise and improve behaviour in various animals," van der Groen wrote for The Conversation last week. "For example, crayfish were shown to be better at avoiding predators when a small amount of random electrical currents were added to their tail fins. Paddlefish caught more plankton when small currents were added to the water."
In human experiments, where noise levels were manipulated by getting participants to listen to noisy sounds or feel random vibrations on the skin, people were better able to see, hear and feel at “a certain optimum noise level.” If it were too loud, however, performance dropped.
Van der Groen pointed out that stochastic resonance has several real life applications for humans, too. "Adding noise to the feet of people with vibrating insoles can improve balance performance in elderly adults," he wrote. For patients with diabetes or those recovering from stroke, this can also be used to augment muscle function.
His own research has found that when brain currents are applied to participants' brains with random noise stimulation, "it improved how well they could see a low-quality image." When he and other researchers applied the same technique to other groups, they noticed "decisions were more accurate and faster when brain cell noise levels are tuned up." Transcranial random noise stimulation also influenced what participants saw during a visual illusion, suggesting noise could help people approach a situation from multiple perspectives.
But the thing about stochastic resonance is it differs from person to person.
The optimal amount of noise for top-notch cognitive function depends on a variety of factors, such as brain variability. Excessive brain variability, van der Groen wrote, is common in those with autism, dyslexia, ADHD and schizophrenia. Elderly folks also tend to have more brain noise (or brain variability) than younger individuals.
However, because brain noise can be altered with random noise stimulation, van der Groen believes there are opportunities to explore “interventions or devices to manipulate noise levels, which could improve cognitive functioning in health and disease.”
For example, a study of children with ADHD found white noise delivered specifically through Etymotic earphones at 77 decibels improved memory and concentration.
Plenty of downloadable ambient, white and "pink" noise apps have also popped up in recent years. There's Coffitivity, which plays an infinite loop of coffee-shop sounds — and Noisli, which suggests different sounds for different goals. If you want to improve productivity, you might mix raindrops and train tracks. For those who want to relax, listen to crashing waves.
Generally, ambient noise is ideal for creativity, white noise is sound for concentration and pink noise might be most helpful in improving sleep quality. But remember, finding stochastic resonance isn’t a one-size-fits-all process. Play around and see which background noises and volumes work best for you.
This guide from Techlicious is a good place to start.