Some people can use ancient muscles to move their ears in small increments
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The “useless” muscles that enable some people to move their ears in small increments are actually activated when we are anxious and listening attentively.
Despite our ape ancestors losing the ability to rotate their ears over a million years ago when they diverged from monkeys, remnants of the muscles and brain neurons that supported this trait still exist in modern humans.
Many scientists believed that these so-called vestigial muscles were obsolete even if they allowed for ear movement, but in 2020, Daniel Strauss from a German University and his team discovered that they are actually activated during focused listening. Various directions were explored to see if people would unconsciously move their ears while concentrating on auditory tasks.
To investigate this phenomenon, researchers recruited 20 individuals with typical hearing, aged 22 to 37, to undergo three challenging hearing tests. Electromyography sensors were used to measure the electrical activity in the muscles around the ears while the participants listened to a 5-minute audiobook excerpt narrated by female voices.
In a simple test, researchers played a soft podcast in the background with a male voice while the audiobook was being narrated. In a moderately difficult task, they introduced a subtle clip of a woman’s voice alongside the audiobook. The most challenging test involved increasing the volume of both background clips.
Researchers found that the largest auricular muscle was most active during the toughest test. Strauss commented, “It’s surprising to see these forgotten muscles work hard when engaged in attentive listening.”
While the team did not determine if this muscle activation aided the participants’ focus on the main audiobook, they suggested that objective measures of listening effort could be obtained through muscle activity monitoring, potentially aiding in the development of improved hearing aids to reduce listening strain.
However, further large-scale research involving participants of various ages and hearing capacities is required to verify these findings, as stated by Yusuf cakmak from Otago University in New Zealand. The team did not investigate the ear movement or expression that might influence auricular muscle activity.
Strauss looks forward to addressing these points in future studies. “To comprehend the ‘neural fossil’ in our brain and its utilization, further research is essential,” he added.
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Source: www.newscientist.com
