When the dance floor is a wasteland, cranking the bass is one surefire way to fill it with bobbing heads and frenetic gyrations.
A new study led by researchers from McMaster University in Canada suggests the groove that comes courtesy of deep frequencies doesn’t even need to be audible. Your body will appreciate the sweet, sweet low frequency tones, even if your ears don’t hear them.
Music and all its components – beat, rhythm, and melody – connect with our brains on deeply emotional levels. Some aspects are almost certainly cultural; others affect our behavior on a cortical level, stirring nostalgia as they summon memories of joy and heartbreak.
But there could also be a part of music that bypasses the usual channels and worms its way into our neurology from the ground up.
Scientists and DJs alike know the advantages a thumping deep beat has over higher-pitched rhythms. Lower frequencies convey the timing of movement better, for example, and are better at triggering responses in our nerves.
We don’t just hear deep frequencies with our ears, either – we feel them crawl beneath our skin, shake the marrow of our bones, and ripple through the very machinery that gives us our sense of balance. It’s a sensation that inspires movement at a very visceral level.
“Music is a biological curiosity – It doesn’t reproduce us, it doesn’t feed us, and it doesn’t shelter us, so why do humans like it and why do they like to move to it?” says the study’s first author Daniel Cameron, a neuroscientist from McMaster University and avid drummer.
Being the socially complex animals we are, it’s possible the mere tingle of a lush bass works on a conscious level, bringing us together to swing our arms and legs madly on the dance floor.
But Cameron and his team wondered if there was something more to the arousing sensations we experience within, something that doesn’t require our awareness.
To test their hypothesis, the researchers turned a live electronic music event into a laboratory experiment at their specially designed theater, plugging in a set of very-low frequency (VLF) speakers at a range on the cusp of human hearing (8 to 37 Hertz) and turning them on and off during the gig. The attendees’ movements were then measured by motion-capture headbands.
The team compared normalized measures of head movement with those captured during 2.5-minute segments of VLF activation followed by 2.5 minutes of inactivation throughout the 55-minute-long event.
Even though it was confirmed the sounds coming from the speakers were undetectable to the dancers, the researchers found on average the participants moved nearly 12 percent more when the VLF speakers were on.
A follow-up questionnaire confirmed the participants felt the music’s bass and enjoyed it, but didn’t distinguish the sensation as different from their usual music experience.
“The study had high ecological validity, as this was a real musical and dance experience for people at a real live show,” says Cameron.
Since most music events don’t blast their patrons with insanely low frequencies, the researchers were confident in concluding the VLF didn’t stimulate the dancers on a conscious level.
Still, even without their awareness, the inaudible beat shook the participants into a groove. Exactly how, whether by stirring the fluids in their inner ears or by stroking their skin’s tactile nerves like a lover within, isn’t clear.
However it works, Cameron and his team are intrigued by the implicit actions of bass affecting our behavior on a subcortical level.
“Very low frequencies may also affect vestibular sensitivity, adding to people’s experience of movement,” says Cameron.
“Nailing down the brain mechanisms involved will require looking at the effects of low frequencies on the vestibular, tactile, and auditory pathways.”
This study was published in Current Biology.