In my book, The Body Of Evidence: How the Human Body Refutes Intelligent Design I list very many examples of the sort of design only a fool would produce - examples of sub-optimal compromises in structures and processes that could have been less error-prone and more efficient in terms of resource use or function.
These also included vestigial structures and system that still exist, sometime causing problems such as appendicitis when the functionless appendix becomes infected, and the wasted metabolism in making all the tiny hairs on your body stand up in cold weather using the tiny arrector pili muscles and the autonomic nerves that supply them.
Now we have another example, involving the superior and posterior auricular muscles that once moved the ears in a remote simian ancestor, but now only serve as party tricks for the few of us that can wiggle our ears.
What information do you have on the superior and anterior auricular muscles in humans? The superior auricular and anterior auricular muscles are two of the extrinsic auricular muscles, which help move the external ear (auricle). These muscles are generally vestigial in humans but can still function in some individuals.A team of researchers from Saarland University in Germany, led by Andreas Schröer has shown that the nerves that control these muscles fire in response to sounds, trying to move our ears to focus on the source of the sound, just like cats and dogs move their ears. And yet, for most people, the muscles are useless and for those few of us who can move our ears, the movement isn't enough to bring the sound into sharper focus. In other words, it's yet another vestigial fossil of our evolutionary ancestry.
Clinical and Evolutionary Notes
- Superior Auricular Muscle
- Location: Positioned above the auricle, extending from the epicranial aponeurosis (galea aponeurotica) to the upper part of the ear.
- Function: Pulls the auricle upward. However, in most humans, this movement is minimal.
- Innervation: Facial nerve (CN VII).
- Anterior Auricular Muscle
- Location: A thin muscle located in front of the auricle, connecting the temporal fascia to the helix.
- Function: Pulls the auricle forward. Like the superior auricular muscle, its function is limited in most people.
- Innervation: Facial nerve (CN VII).
- In animals with mobile ears (like cats and horses), these muscles are more developed and essential for sound localization.
- Some humans retain the ability to wiggle their ears due to minor contractions of these muscles, though this is rare and often a learned skill.
- Dysfunction or facial nerve damage can affect these muscles, though their role in facial movement is negligible compared to other muscles of facial expression.
The team’s findings are published, open access, in the journal Frontiers in Neuroscience:
Recently, electromyographic (EMG) signals of auricular muscles have been shown to be an indicator of spatial auditory attention in humans, based on a vestigial pinna-orienting system. Because spatial auditory attention in a competing speaker task is closely related to the more generalized concept of attentional effort in listening, the current study investigated the possibility that the EMG activity of auricular muscles could also reflect correlates of effortful listening in general. Twenty participants were recruited. EMG signals from the left and right superior and posterior auricular muscles (SAM, PAM) were recorded while participants attended a target podcast in a competing speaker paradigm. Three different conditions, each more difficult and requiring a higher amount of effortful listening, were generated by varying the number and pitch of distractor streams, as well as the signal-to-noise ratio. All audio streams were either presented from a loudspeaker placed in front of the participants (0°), or in the back (180°). Overall, averaged PAM activity was not affected by different levels of effortful listening, but was significantly larger when stimuli were presented from the back, as opposed to the front. Averaged SAM activity, however, was significantly larger in the most difficult condition, which required the largest amount of effort, compared to the easier conditions, but was not affected by stimulus direction. We interpret the increased SAM activity to be the response of the vestigial pinna–orienting system to an effortful stream segregation task.Yet another example of how the human body was not intelligently designed but results from a mindless, utilitarian process in which vestigial structure that serve no purpose are retained because there is little or no environmental pressure to remove them. Perhaps a creationist might like to explain these muscles complete with nerves and the reflex arc leading from the auditory apparatus that fires them, would have been created by an intelligent designer when they serve no known function in humans.
Schroeer, Andreas; Corona-Strauss, Farah I.; Hannemann, Ronny; Hackley, Steven A.; Strauss, Daniel J.
Electromyographic correlates of effortful listening in the vestigial auriculomotor system
Frontiers in Neuroscience; 18 DOI: 10.3389/fnins.2024.1462507
Copyright: © 2025 The authors.
Published by Frontiers Media S.A. Open access.
Reprinted under a Creative Commons Attribution 4.0 International license (CC BY 4.0)
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