Our distant ancestors had different parts of the body that have become fairly useless in the course of evolution – our wisdom tails that are present during the Sixth week of pregnancyAnd the auricular muscles in our ears. The auricular muscles helped to change the shape of the scale or pina – from the ear and helped people who lived millions of years ago, listen well. They are still getting around 10 to 20 percent From people with the fun capacity to wiggle their ears.
These, however remnant Can be used more than scientists ever believed. The Auricular muscles seem to activate when people try to listen to competing sounds, not just when wiggling the ears. The findings are detailed in one Study published on January 31 in the magazine Frontiers in neuroscience.
“There are three large muscles that connect the earcup with the skull and the scalp and are important for earcuds,” Andreas Schröeer, co-author and neuroscientist of Saarland University in Germany, said in a statement. “These muscles, especially the superior auricular muscle, show increased activity during strenuous listening tasks. This suggests that these muscles are not only involved as a reflex, but possibly as part of a attention effort mechanism, especially in challenging auditory environments. ”
Sounds fighting for attention
This New study used a technique called electromyography To try to determine how hard someone listens without asking individuals to report this. Electromyography measures the electrical activity in a muscle and can help scientists determine activity in the auricular muscles that is already linked to listen carefully. Similar research found the largest muscles – posterior and superior auricular muscles – Response during attentive listening. These muscles pull up and back and scientists believe that they have been historically involved in moving the Pinna to catch sounds.
“The exact reason that these remains are difficult to say is, because our ancestors lost this assets about 25 million years ago,” Schröeer said. “A possible explanation could be that the evolutionary pressure to move around the ears stopped because we became much more competent with our visual and vocal systems.”
To see if these muscles are more active during more difficult listening tasks, the team studied 20 people without documented hearing problems. They first put electrodes on the auricular muscles of the participants. Then they played an audio book and a few distracting podcasts from speakers placed in front of or behind the listeners. All 20 participants underwent 12 tests of five minutes, with regard to Three different levels of difficulty.
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During the easy mode, the podcast was quieter than the audio book, while the speaker’s voice was a stronger contrast with the audio book. In the medium and difficult modes, the researchers added a podcast that looked more like the audio book and made the distractors louder. However, they even had to make the most difficult situations feasible, because if the participants gave up, a physiological effort would not register on the machines.
The team then asked the participants in the study to assess their effort level and to estimate how often they lost what was going on during the audio book in every test. Participants were also questioned about the material in the audio book.
Just do his best
The team thought that Two auricular muscles responded differently to the different circumstances. The rear auricular muscles responded to changes in direction. For comparison: the superior auricular muscles responded to the difficulty level of the task. The self -reported measures of the participants on how difficult it was to listen and how often they lost the audio book also increased in line with the difficulty of the task. The accuracy of their answers to questions about the audio book also decreased considerably between the medium and the difficult mode.
According to the authorsThis correlated with the activity levels of the superior auricular muscles. These muscles no longer activated during medium -sized mode than during simple mode, but were very active during difficult mode. This suggests that the activity of these muscles could offer an objective degree of listening effort. However, it remains unclear whether the muscle activity actually helps people to hear better.
“The ear movements that can be generated by the signals we have recorded are so minuscule that there is probably no perceptible advantage,” Schröeer said. “However, the earcup itself contributes to our ability to locate sounds. So our auriculomotor system probably tries to be his best after being 25 million years, but does not achieve much. ”
Additional research is necessary to confirm the results and to develop practical applications. Like many hearing studies, the The sample size was relatively small and consisted of younger people without hearing problems. Larger and more diverse participant groups that are tested in more real circumstances are needed to say that these muscles do more than just in our ears.
“Investigating the possible effects of muscle load itself or the tiny movements of the ear on the transfer of sound is something that we want to do in the future,” Schröer said. “The effect of these factors in people with hearing disorders would also be interesting to investigate.”
