Mind & Body

Scientists Have Created an Audio Map of Emotions Using Only Noises

If you've ever spent hours pondering an ambiguous text, it's not just you — it's the medium. Language is important, obviously, but its message is clearer when it's accompanied by body language, facial expressions, tone of voice, and non-word sounds. That's right: Humans can convey a surprising array of emotions through wordless noises, or "vocal bursts."

Related Video: Are Emotions Contagious?

Bursting With Feeling

You don't hear a lot of casual conversation about vocal bursts, because colloquially, they go by other names: laughs, sighs, shrieks, roars, oohs, and ahhs, to name a few. In emotion science, researchers use the umbrella term "vocal burst" to encompass all these "brief human vocalizations."

(Yep, emotion science is an emerging field of psychology, with its own journal and everything.)

Past studies have established that people can recognize 13 emotions in vocal bursts. However, these studies have also relied heavily on forced-choice questions, like "Which of these four vocal bursts fits this scenario best?" This question structure restricts responses; if a vocal burst conveys a mix of feelings, for instance, the answer can't capture that. So in a recent paper published in American Psychologist, researchers put forward a new hypothesis: Listeners can recognize more than 20 emotions in vocal bursts.

To test this theory, they amassed an audio library of more than 2,000 vocal bursts and asked more than 1,000 people to evaluate them with one of three methods. Some rated the vocal bursts on the 13-item affective scale popular in previous emotion science research, which included spectrums of dominance, safety, and arousal. Others described the bursts in free responses, and a third group assigned the bursts to one of 30 emotional categories, including love, relief, and disappointment.

When they combined the forced-choice and free-response descriptions to find their commonalities, they ended up with 24 reliable emotional categories. The categories were (drumroll, please!): adoration, amusement, anger, awe, confusion, contempt, contentment, desire, disappointment, disgust, distress, ecstasy, elation, embarrassment, fear, interest, pain, realization, relief, sadness, positive and negative surprise, sympathy, and triumph.

Already, this is a pretty exciting finding. Who knew we could understand so many feelings from sound alone — or that we could distinguish the sounds of disgust and contempt?

The Sound of Mixed Feelings

Researchers didn't stop there, though. They were also interested in the borders between emotions. Were they rigid — so, could a vocal burst convey disgust or contempt, but never both? Or could a vocal burst convey mixed emotions, too?

They found the latter. The borders between emotions were fuzzy, and there were gray areas between some feelings. Some vocal bursts fell in between elation and triumph, or negative surprise and fear. That said, not every feeling shaded into every other feeling. Researchers didn't find any vocal bursts that fell halfway between, say, relief and anger. (Yet!)

The best part about this research? To show the emotional gradients they found (and didn't find) in vocal bursts, the researchers accompanied their paper with an interactive map of audible feelings, color-coded by category. "Desire," for instance, appears on the map in a dark eggplant font; every eggplant-colored letter near it signifies an (at least faintly) desirous vocal burst. If you click on a letter, the corresponding burst plays on your speakers. We recommend headphones!

We also recommend clicking around. If the study of vocal burst strikes you as faintly frivolous, hearing a few for yourself could change your mind. You'll realize not only how clearly you understand these wordless sounds, but also how often you hear them. In many cases, even among chatty adults, they communicate feelings and mood more clearly than words.

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For more on the mysteries of emotion, check out "How Emotions Are Made: The Secret Life of the Brain" by Lisa Feldman Barrett. We handpick reading recommendations we think you may like. If you choose to make a purchase, Curiosity will get a share of the sale.

Written by Mae Rice February 25, 2019

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