Ear muscle we thought humans didn't use activates when people listen hard

Personal Experiences with Ear Muscles

• Many commenters report a clear reflex: sudden sounds behind them cause a distinct ear-muscle contraction, often linked to startle responses or “pricking up” ears like a cat or dog.
• A sizable group can voluntarily wiggle their ears; some say they trained this in childhood by trial-and-error using a mirror or touching the muscle area, others say it felt innate/genetic.
• Asymmetry is common: some can move only one ear, or one more strongly; similar anecdotes appear for eyebrows, nostrils, tongue, and toes.
• Several people feel their ears subtly engage when “listening hard” (e.g., to faint or foreign speech, or with earbuds/ANC), even if their ears don’t visibly move.
• Others are surprised to learn that many people cannot move ears, eyebrows, or nostrils at all.

Tensor Tympani and “Ear Rumbling”

• Multiple commenters describe consciously contracting an inner ear muscle that produces a deep rumbling sound and can slightly reduce external noise.
• Others use a similar motion to help equalize ear pressure (airplanes, diving) instead of or in addition to maneuvers like Valsalva; it sometimes also opens Eustachian tubes.
• Several link this to the tensor tympani muscle and note a subreddit dedicated to the phenomenon; some note it may be more common than literature suggests.
• Hyperacusis and car safety systems that pre-trigger this reflex with pink noise are mentioned as related to the same muscle.

Evolution, Vestigiality, and “Useless” Parts

• Some object to the headline’s implication that humans “didn’t use” the muscle, arguing evolution tends to eliminate structures with zero function; they distrust claims that body parts “do nothing.”
• Others counter that:
  • Vestigial does not mean entirely useless; organs can retain minor or secondary roles.
  • Weak selection, late-life risks, and genetic drift allow many low-impact traits and organs to persist.
  • Evolution gets stuck in local optima and doesn’t systematically optimize every inefficiency.
• The appendix and tonsils recur as examples where “useless” labels were later softened as immune or microbiome roles were found; still, appendicitis risk vs benefit is debated.
• Analogies are made to “junk DNA” (now “non-coding”) and to Chesterton’s Fence: be cautious about declaring something purposeless before understanding it.

Human Movement, Senses, and Research Limits

• One thread notes that fine-grained human movement science is still immature: motion capture and current sensors don’t resolve small muscle groups well, and elite subjects are scarce.
• Commenters speculate our ancestors may have routinely used ear, eye, and other subtle controls more, and note growing acceptance that humans can learn skills like echolocation or partial control over pupils.

Possible Uses and Open Questions

• Some see potential for using these ear-muscle signals to control devices (e.g., prosthetic or “cat ear” wearables, or directional hearing aids).
• Others argue that activation alone doesn’t prove meaningful utility; the muscle might be largely vestigial despite residual reflexive or conscious control.