Have you ever been so focused on your thoughts that you didn’t hear a noise? Or been somewhere so loud you couldn’t hear yourself think?
It’s not just hyperbole. There actually is a connection between how loud your internal voice is and how loud you perceive the external world, a new study finds.
Researchers at New York University, NYU Shanghai and Zhejiang University in China recently published their findings in a paper called "Imagined speech influences perceived loudness of sound."
David Poeppel, a professor of psychology and neural science at NYU who was involved in the research, said that this helps us better understand how our own brains work.
“What the study is actually about is testing something very specific about how speech production works,” he said. “When your thoughts are translated into words — when you plan on saying them — you plan even how loud something's going to be. You can use that as a test to figure out how loud you experience the environment.”
For the study, researchers asked people to think of a word and say it either very loudly or very quietly to themselves. Participants never said anything out loud or even moved their mouths, he noted, just simply shouted something in their head.
Researchers then played a tone out loud and the participants had to rate how loud that noise seemed on a scale of one to 10.
When someone thinks with a “loud” internal voice, external noises sound quieter, the study found.
“Suppose I ask you to please shout ‘cat’ in your head, then right afterward I play a sound. You’ll actually imagine that sound to be soft, because the sound in your head is so loud,” Poeppel explained. “And vice versa, if you imagine saying it softy, you imagine the [external] sound to be louder.”
Researchers repeated the experiment multiple times, using just behavioral ratings from the participants and then using two different kinds of brain imaging technology during the process. The results were the same each time.
“The idea is when you turn a thought into a word, when you’re planning to say it, before you’ve even moved your lips or tongue or anything, it’s already been turned into a sound,” Poeppel said. “It’s been turned into a sound in the future, basically.”
These findings could help influence a lot of further research on everything from stuttering to schizophrenia, but are important mainly because they move us closer to understanding “how our brains work and how they interact with the external world,” he said.
That interaction may end up being distracting sometimes. This may show that loud noises in the world are “competing” with the noises in our heads, Poeppel said — so the next time someone yells at you when you’re lost in thought, you can honestly say you didn’t hear them.