Enjoy the Science of Silence: We Hear Silence Just Like Other Sounds

As our world grows louder by the day, more and more people are searching for a little silence. Now, a new study suggests that our brains can hear silence in the same way it perceives sound.  

Simon and Garfunkel were onto something

A research team of psychologists and philosophers from Johns Hopkins University has now published the results of a study that inventively used auditory hallucinations to test exactly how the brain senses the sound of silence.

The study has been published in the journal Proceedings of the National Academy of Sciences.

Auditory illusions, which play with the intensity or length of replayed sounds to alter how we perceive them, have been valuable tools in our study of the auditory system. The Johns Hopkins team played with these illusions by replacing sound with silence. In one classic illusion – the “one is more” test, two sets of sounds are played. The first is a single long beep and the second is a pair of short consecutive beeps. Even when the two sequences are the same length, listeners hear the lone beep as being longer overall. In the new study, listeners were played audio from loud environments – packed diners, crowded train stations and bustling marketplaces. Then, they added silence. The results suggested participants perceived a single gap of silence as being longer than a pair of gaps interspersed with a heard tone. 

Exploring absence

Chaz Firestone, an Assistant Professor of Psychological and Brain Sciences who directs the Johns Hopkins Perception & Mind Laboratory, said that the similar results, amassed from testing over 1,000 volunteers, indicate that people hear silence just like sound. "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. “Our approach was to ask whether our brains treat silences the way they treat sounds. 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."

This breakthrough research provides a new paradigm to explore the perception of absence. The researchers now plan to explore other forms of perceptual emptiness – such as visual disappearances – to see whether these absences are perceived similarly.

Reference: Goh RZ, Phillips IB, Firestone C. The perception of silence. Proc Natl Acad Sci USA. 2023;120(29):e2301463120. doi: 10.1073/pnas.2301463120