Playing natural sounds such as flowing water in offices could boost worker moods and improve cognitive abilities in addition to providing speech privacy, according to a new study from researchers at Rensselaer Polytechnic Institute.

An increasing number of modern open-plan offices employ sound masking systems such as “white noise” that raise the background sound of a room so that speech is rendered unintelligible beyond a certain distance and distractions are less annoying.

“If you’re close to someone, you can understand them. But once you move farther away, their speech is obscured by the masking signal,” said Jonas Braasch, an acoustician and musicologist at the Rensselaer Polytechnic Institute in New York.

Braasch and his team are currently testing whether masking signals inspired by natural sounds might work just as well, or better, than white noise. The idea was inspired by previous work by Braasch and his graduate student Mikhail Volf, which showed that people’s ability to regain focus improved when they were exposed to natural sounds versus silence or machine-based sounds.

Recently, Braasch and his graduate student Alana DeLoach built upon those results to start a new experiment.

They are exposing 12 human participants to three different sound stimuli while performing a task that requires them to pay close attention: typical office noises with the conventional random electronic signal; an office soundscape with a “natural” masker; and an office soundscape with no masker. The test subjects only encounter one of the three stimuli per visit.

The natural sound used in the experiment was designed to mimic the sound of flowing water in a mountain stream. “The mountain stream sound possessed enough randomness that it did not become a distraction,” DeLoach said. “This is a key attribute of a successful masking signal.”

They want to find out if workers who are listening to natural sounds are more productive and overall in better moods than the workers exposed to traditional masking signals.

Braasch said using natural sounds as a masking signal could have benefits beyond the office environment. “You could use it to improve the moods of hospital patients,” for example, Braasch said.

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Abstract of Tuning the cognitive environment: sound masking with “natural” sounds in open-plan offices

With the gain in popularity of open-plan office design and the engineering efforts to achieve acoustical comfort for building occupants, a majority of workers still report dissatisfaction in their workplace environment. Office acoustics influence organizational effectiveness, efficiency, and satisfaction through meeting appropriate requirements for speech privacy and ambient sound levels. Implementing a sound masking system is one tried-and-true method of achieving privacy goals. Although each sound masking system is tuned for its specific environment, the signal – random steady state electronic noise, has remained the same for decades. This session explores how “natural” sounds may be used as an alternative to this standard masking signal employed so ubiquitously in sound masking systems in the contemporary office environment. As an unobtrusive background sound, possessing the appropriate spectral characteristics, this proposed use of “natural” sounds for masking challenges the convention that masking sounds should be as meaningless as possible. Based on psychophysical data and a sound-field analysis through an auditory model, we hypothesize that “natural” sounds as masking sounds have the ability (with equal success as conventional masking sounds) to meet standards and criteria for speech privacy while enhancing cognitive functioning, optimizing the ability to concentrate, and increasing overall worker satisfaction.