Does my voice sound “normal”? It’s complicated, new research suggests

When it comes to our voices, we may think we know the difference between what sounds “normal” and what makes us turn off the radio. But what constitutes a normal voice, and how have we come all to that conclusion?

Researchers from UCLA investigated what it means to have a normal-sounding voice, and have found that while we can agree on what sounds abnormal, it’s a little more difficult to pinpoint what a normal voice actually sounds like.

“Voices carry many, many kinds of information about the speaker – their personal identity, age, sex, health, reproductive fitness, dominance, mood/personality, benign/malign intentions, on and on,” Jody Kreiman of the Department of Head and Neck Surgery and Linguistics at the University of California, Los Angeles, tells Alphr.

“A lot of this functions the same way in other animals, and the signals have evolved over time to produce appropriate responses in listeners (fear, alliance, approach/avoid). When we hear a voice that sounds abnormal, we may automatically have negative feelings about the intelligence, health status, and social status of the individual, not just because the voice sounds ‘bad,’ but because this is wired into us.”

While Kreiman says these inherent vocal biases are often completely incorrect, they’re hard to ignore because of the way we’ve evolved. So, if we’re able to tell what an abnormal voice sounds like, then it follows that we should be able to identify a “normal” voice. Right? Wrong.

In Kreiman’s study, 50 volunteers listened to one-second ‘ah’ vowel recordings produced by 50 females with clinically-diagnosed voice abnormalities, as well as 50 female UCLA students with no known vocal abnormalities. The volunteers were then asked to organise the recordings by perceived severity of “vocal pathology”, scaling the voices from “normal” to “worst”. While the researchers found that the volunteers were sometimes able to agree on voice abnormality, the group weren’t able to agree on what a “normal” voice sounded like.

“We conclude that ‘normal’ isn’t a fixed thing. Instead, it seems to be a dynamic interaction between the listener, the speaker, and the communicative context. What that means is that just about anything can sound not normal to someone in some circumstance,” Kreiman says. “This is consistent with a lot of other things about voice – voices don’t just hang out there as static signals; the particular meaning depends on many factors.”

While there might not be a universal “normal” voice, the researchers found that individually, listeners were self-consistent in the placement of the recordings on the scale. It also doesn’t mean that there isn’t a normal voice. Instead, normal is something that appears to be very personal to each of us. Normalcy to each person differs based on a wide range of things, as Kreiman explained above, but even the results surprised her.

“I thought that at least a few voices would sound normal to everyone; but in retrospect I shouldn’t have been surprised. Meaning in voice (and “normal” is part of the meaning carried) isn’t just a function of the signal, or of the speaker, or of the listener,” Kreiman adds. “Speakers produce sounds in order to transmit information to a listener – otherwise it’s a waste of energy and possibly a source of danger if a predator hears them.

“The way they produce signals thus has to be tuned to what listeners can hear.  Similarly, listeners have to work with the signals that come their way, and their perceptual systems have to co-evolve with voice production systems so that everything can work together efficiently.”

One example she gives me is the sound of a shriek. A shriek in a dark alley late at night provides a very different meaning to the sound of a shriek at a lively party. This mixture of factors influences what people describe as “normal”, suggesting that what people consider normal is going to differ wildly based on the listener listening to the voice. So while we all assume we know what “normal” sounds like, there’s really no such universal thing.

So does your voice sound normal? The answer to that will very much depend on who you’re asking, and where you’re asking them.

Kreiman will present her work on voice normality and perception at the 175th meeting of the Acoustical Society of America taking place in Minnesota from now until 11 May.