Most humans haven’t moved these muscles in 25,000,000 years

Muscles used to wiggle your ears haven't been used by most humans for over 25,000,000 years, yet scientists might just have discovered a hidden important use case that you might not expect.

There's always going to be parts of your body that you don't end up using as much, whether it be simple muscles that become painful after that New Year's resolution gym trip, or evolutionary redundancies like your wisdom teeth.

What many scientists considered to be one of the most useless muscles in your body though is the auricular muscles in our ears.

These, as reported by Popular Science, helped change the shape of our ears, and also assisted in the close hearing of humans around 25,000,000 years ago, yet now they're reserved for a meaningless task.

Muscles in your ear could have a hidden evolutionary purpose (Eric Baradat/AFP via Getty Images)

If you're one of the roughly 10 to 20% of people who are able to wiggle your ears up and down then you've achieved mastery of your auricular muscles - but recent discoveries have indicated that they're useful for far more than a funny party trick.

One study in the journal Frontiers in Neuroscience has indicated that your auricular muscles are actually used to distinguish between competing sounds, as indicated by electromyographic (EMG) signals.

"Because spatial auditory attention in a competing speaker task is closely related to the more generalized concept of attentional effort in listening," the abstract outlines, "the current study investigated the possibility that the EMG activity of auricular muscles could also reflect correlates of effortful listening in general."

Studying EMG signals helps scientists understand how the auricular muscle moves (Frontiers in Neuroscience/A. Schroeer et al.)

What EMG activity affords is the study of how 'hard' someone is listening without actually asking them, as activity within the auricular muscles reacted differently to the various tests that participants were put through.

Participants were subject to competing sounds from a podcast and an audiobook, with increasing volumes and distractions in order to indicate if the auricular muscles work harder.

It became clear that increases in the participant's efforts to discern the sounds directly correlated with amplified auricular muscle activity, outlining that "an increased activity of the vestigial pinna-orienting system could be interpreted as an attempt to alter the shape of the pinna or ear canal."

What's intriguing is that while the movement are definitely there and a fragment of human activity millions of years ago, it's not actually known whether these movements actually help in discerning competing sounds.

"Especially in the current experimental setup, without any spatial separation between target and distractor, orienting the pinna would be futile, even though the neural circuits may still activate the auricular muscles and attempt to aid stream segregation."

It's almost like your body maintains ghosts of past evolutions that have become long redundant, but it remains a fascinating discovery that we're still likely a long way from reaching the entire story of.