Nearly 60 years after American folk duo Simon & Garfunkel sang their dangerously earworm-y tune “The Sound of Silence,” a team of researchers has resurrected the age-old question as to whether the absence of noise in itself is something we can actually hear.
“We typically think of our sense of hearing as being concerned with sounds,” said lead author Rui Zhe Goh, a Johns Hopkins University graduate student in philosophy and psychology. “But silence, whatever it is, is not a sound – it’s the absence of sound. “Surprisingly, what our work suggests is that nothing is also something you can hear."
Zhe Goh, along with cognitive scientist Chaz Firestone and philosopher Ian Phillips, set out to answer one question: Do our minds treat silence and sounds the same way?
“Philosophers have long debated whether silence is something we can literally perceive, but there hasn’t been a scientific study aimed directly at this question,” said Firestone, an assistant professor of Psychological and Brain Sciences at Johns Hopkins. “Our approach was to ask whether our brains treat silences the way they treat sounds.”
The trio performed seven aural experiments featuring three ‘silence illusions’ from well-known auditory illusions and tested these on 1,000 participants. What they found was that the silence-based illusions tricked the brain much like the sound tests did, altering the way the participants assessed the length of sounds and silence.
You can try the experiments here.
“There’s at least one thing that we hear that isn’t a sound, and that’s the silence that happens when sounds go away,” said co-author Phillips, a professor of Philosophy and Psychological and Brain Sciences. “The kinds of illusions and effects that look like they are unique to the auditory processing of a sound, we also get them with silences, suggesting we really do hear absences of sound too.”
The study does not, however, address the physiological aspect of ‘hearing’ silence, given that the transmission of sounds to the brain and subsequent processing is a complex mechanical and neural process based on picking up sound wavelengths, rather than an absence of them.
However, the team says much like optical illusions, our brains interpret the absence with the type of cognition that suggests it could experience silence much like sound.
“If you can get the same illusions with silences as you get with sounds, then that may be evidence that we literally hear silence after all,” Firestone said.
The study was published in the journal Proceedings of the National Academy of Sciences.
For more on the research, see (and hear) the video below.
Source: Johns Hopkins University via EurekAlert