Why Everyone Hears The Same Sounds Differently

By Debra Kelly on Thursday, March 31, 2016
woman suffers from hearing impairment, hard of hearing, hearing loss, acoustic or ear problem, deafness with text space
“Listen to them. Children of the night. What music they make.” —Dracula, “Dracula” (1931)

In A Nutshell

It turns out that the almost endless arguments over the merits of a certain song or certain band might all stem from something physical. Different people really do sometimes hear the same sounds in entirely different ways. Even the smallest differences in our individual skull structure or bone density can change the way our brain receives and processes sound waves, changing the frequency that our bones vibrate at as we hear sounds. That can also impact our ability to understand and process language, and it’s been found that inner ear structures might also impact agility.

The Whole Bushel

Imagine: A song comes on the radio, and one person absolutely loves it. To another person, it sounds a bit like a cross between a screaming child and fingernails on a blackboard. The reason there’s such a difference in the way we hear music and other sounds isn’t just down to different tastes; it’s likely down to the way we’re actually hearing sounds.

The process of how physically hearing sounds translates to experiencing sounds has been a mystery for a long time, but Harvard Medical School has begun breaking it down into its components. When the inner ear receives sounds, it triggers a reaction from the different brain cells that are responsible for transmitting the information to your brain. That triggering forms different types of patterns that, in turn, touch different parts of the brain, explaining why we associate certain sounds with certain memories and feelings.

But we’re still not sure if the process works the same in everyone. The mechanics might be the same, but researchers from the University at Oxford have found that ferrets equipped with auditory implants react differently to the same sounds. The ferrets’ brain activity seems to show that they’re experiencing the sounds slightly differently from each other.

We’re still exploring why that is. But it has at least something to do with the way our skulls are shaped, and the variations in individual bone structures likely has something to do with why we hear the same noise in a slightly different way.

When sound bounces off the structures of the inner ear, it reflects off the ear and off the bones in the head. According to the Acoustical Society of America, even the slightest differences in things like shape and bone density can make a huge difference in the vibrations that we ultimately hear. Women’s skulls tend to vibrate faster than the skulls of their male counterparts, and individuals’ recorded vibrations can vary between as much as 35–65 Hz.

That’s a huge difference, and it’s been linked to what musical chords we find pleasurable or distasteful. It suggests that our likes and dislikes of certain music styles might have a basis in the physical as much as the cultural.

It’s also been linked to something even more surprising: physical prowess. When Penn State University looked at how the structure of the inner ears of chimpanzees impacted things like their physical agility and coordination, they found a definite correlation.

When it comes to hearing, surely, no one should be better at it than musicians, right? Studies—including one where both professional musicians and non-musicians were asked to pick out certain voices from a noisy room—have shown that the entire auditory system of a musician is different. Signals that indicate things like tone and pitch are much stronger when they travel through a musician’s brain than through the brain of a non-musician. Plus, it’s been found that exposing children’s brains to music may help them learn to process other things, like language and math, with greater efficiency.

Figuring out the exact differences in how we process sound might explain why we love or hate certain kinds of music, but there’s a more practical reason for the research, too. It has the potential to help in the creation of more efficient hearing aids, and it might also help programmers improve speech recognition programs.

Show Me The Proof

Harvard: How Your Brain Listens to Music
Scientific American: Same Old Song May Sound Different To Individuals
Inside Science: How skull resonance influences musical preference
NPR Music: Say What?! Musicians Hear Better