These muscles once allowed us to move our ears. What are they used for now? 👂

Millions of years ago, our ancestors were able to move their ears to better capture sounds, much like dogs or cats. But with evolution, this ability gradually faded, leaving behind muscles that are now useless... or almost. Researchers have indeed discovered that these muscles are not completely inactive: when a person focuses on a sound, they subtly activate, like a forgotten remnant of a distant past.

The auricular muscles: a dormant evolutionary heritage

The auricular muscles once had an essential role: they allowed our ancestors to pivot their ears to more effectively locate surrounding sounds, whether it was an approaching predator or a source of food. This ability is still clearly visible in many mammals, such as felines that orient their ears towards the slightest suspicious noise.

But in modern humans, sight and verbal communication have gradually taken precedence over this auditory ability. As a result: the auricular muscles have lost their primary function and have become residual structures. Yet, although they no longer allow effective ear movement, they continue to activate in certain situations...

A hidden activity revealed by science

A team of researchers from Saarland University in Germany, in collaboration with American scientists, recently discovered that these muscles are not completely inert. By placing electrodes on the ears of volunteers, they observed activation of the auricular muscles when an individual tries to focus on a specific sound, especially in a noisy environment.

The experiment involved having twenty participants listen to an audiobook, while sometimes adding a disruptive background noise, such as another podcast playing simultaneously. Result: the more demanding the listening task, the more the superior and posterior auricular muscles contracted, as if they were instinctively trying to orient the ears towards the sound source, although this movement is now imperceptible.

Why do these muscles still activate?

This discovery raises an intriguing question: why do these muscles continue to react if we can no longer orient our ears? Researchers propose a hypothesis: it could be a reflex related to attentional effort. In other words, when listening becomes difficult, our brain unconsciously mobilizes these vestigial muscles, like an old evolutionary habit that we have never completely lost track of.

The study shows that this reaction is particularly marked when the sound comes from behind or an unusual direction. Another interesting fact: if the participant stops making the effort to listen, the muscle activation disappears immediately, confirming that it is not just a simple reflex, but rather a response to the degree of concentration.

Towards new applications?

Although these tiny muscle contractions do not directly improve our hearing, they could have interesting applications. For example, they could serve as an objective indicator to measure a person's auditory attention. In the long term, this discovery could even pave the way for new approaches in the study of hearing or attention disorders.

Ultimately, our auricular muscles are a reminder of our evolutionary past: while they no longer allow us to move our ears like an alert cat, they testify to the ingenuity of the human body, which retains traces of its history, even when they no longer seem to have immediate utility.