In a major discovery that is likely to change what we know about sound and human hearing, scientists have discovered that humans actually have the ability to hear silence
New evidence from researchers suggests that the brain actively processes silence, shedding light on why we pay close attention to moments of silence in conversations, suspenseful gaps between thunderclaps, or the quietness at the end of a musical performance.
This claim is supported by seven experiments involving 1,000 participants, which demonstrated that the mind can be deceived by silence in a similar manner to sound. Similar to how tricks with sound can manipulate perception, such as playing continuous or separate electronic tones, the study found that individuals perceive one continuous silence as lasting longer than two separate silences.
Dr Chaz Firestone, the senior author of the study from Johns Hopkins University, remarked on the paradoxical nature of silence and how these findings suggest that our brains process silence as if it were a sound. He mentioned that there may be some truth to the phrase “the sound of silence” after all.
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The study, published in the journal Proceedings of the National Academy of Sciences, presented single and double silences to participants in the presence of background noise, including a train, a busy restaurant, a bustling market, a playground, or white noise. When asked to compare, people judged the single silence as longer than the two separate silences, mirroring their perception of sounds.
The illusion persisted when participants were asked to indicate the duration of the silences by pressing a key or simply comparing them. To ensure that the surprise of silence being interrupted by noise did not influence judgments, the researchers repeated the experiment with a chirping bird noise during the longer silence. They also discovered that silences played between other sounds were perceived as having a larger gap, strengthening the idea that our brains actively perceive silence.
Since everyday life is filled with a constant symphony of sounds, true silence is rare. Therefore, the researchers examined how people responded when a single sound abruptly ceased. By playing a high-pitched organ tone and a low rumbling engine simultaneously, and intermittently muting one of the sounds, they found that individuals perceived the sound that had not previously disappeared as being silent for a longer duration when it was removed unexpectedly.
These various audio illusions demonstrate the innate predisposition of our brains to perceive and process silence. The researchers conclude that the effects observed, which are typically associated with auditory processing of sound, also apply to silences, suggesting that we do indeed perceive absences of sound.
