Our distant ancestors had some parts of the body that were quite useless in the evolution process. 6th week of pregnancyAnd our ears of our ears. The muscles of the anchle helped to change the shape of the ear shells, helping people who have lived thousands of years ago to listen. They are still roughly used 10-20 % People who have fun moving their ears in small pieces.
However, these Trace muscles It may be more used than a once believed scientist. The muscles of the anchle seem to be activated not only when humans are shaking their ears, but also when they are trying to hear the competitive sound. For details on the survey results Studies published in the journal on January 31st Neurology Frontier。
“There are three large muscles that connect the anchoric to the scalp and the scalp, and it is important for the shaking of the ears,” said Andreas Schleae, a co -author and neuroscientist in Surland in Germany. I said in a statement。 “These muscles, especially good auroral muscles, increase their activities during the efforty listening tasks. This is not only these muscles as a reflection, but especially in the challenging hearing environment. It suggests that it is a potential part of. ”
It sounds like it’s attracting attention
this New study I used the called technique Electrocardiogram Instead of asking to report to the individual, we try to determine how difficult it is. Muscular maps can help you measure muscle electrical activities and identify the activity of the scientists who are already listening to them. Similar research I discovered that the biggest muscles (rear and upper nurtosis) reacted Attentive listening。 These muscles are raised and pulled up to their backs, and scientists believe that they have been historically involved in moving Pina to capture the sound.
“It is difficult to convey the exact reason why our ancestors lost this ability about 25 million years ago,” said Schleae. “One of the possible explanations is that the visual system and the vocal system were much more skilled, so the evolutionary pressure of moving the ears stopped.”
The team studied to see if these muscles were more active in the more difficult listening task. 20 people without a documented hearing impairment。 They first placed an electrode on the participant’s an electrode. Later, they played an audiobook and a podcast that distracted from the speakers placed in front of or behind the listeners. All 20 participants took 12 tests and covered them. Three different levels of difficulty。
[ Related: Yes, humans are still evolving. ]
In simple mode, podcasts were quieter than audiobooks, but the speakers were in contrast to audiobooks. In the middle and difficult modes, researchers have added podcasts that sound like an audiobook and enlarged the distractor. However, if the participants gave up, the physiological efforts were not registered in the machine, so even the most difficult situation could be achieved.
Later, the team asked the investigators to evaluate the level of effort and estimate the frequency of losing what was happening during the audiobooks in each trial. Participants were also quizzed by audiobook materials.
I’m just doing my best
The team found it The two anoperic muscles showed a different reaction from various conditions.。 The posterior nurse muscles responded to changes in the direction. In comparison, the excellent anoperous muscle responded to the difficulty of tasks. Participants’ self -reporting increased how difficult it was to hear, and the frequency of losing the tracking of the audiobook was increased according to the difficulty of the task. The accuracy of answers to questions about audiobooks has also dropped significantly between medium mode and difficult modes.
According to the authorThis was correlated with the activity level of the primaryulus muscle. These muscles did not activate a lot in the middle mode in the easy mode, but were very active in difficult modes. This suggests that these muscles can provide an objective scale of listening efforts. However, it is unknown whether muscle activities can actually help people listen better.
“The ear movements generated by the signals we have recorded are so small that there is probably no benefit that can be perceived,” said Schröer. “However, the anchle itself contributes to the ability to localize the sound, so our Auriculomotor system probably tried the best attempts after spending traces for 25 million years. I do not.
To confirm the results and develop a practical application, additional research is required. Like many hearing research The sample size was relatively small and was composed of young people without hearing impairment.。 To be confident that these muscles are sitting in our ears with confidence, they have been tested under more realistic conditions. I need a group.
“It is what we want to do in the future to investigate the effects of muscle tension itself or to investigate the very small movement of sound transmission,” said Schrenter. “It will be interesting to investigate the effects of these factors in people with hearing impairment.”