 Bass. The lowest part of a harmony in a musical composition. For centuries we've all shared a similar response to low frequency sound, regardless of our particular preference in music. Across cultures and genres, what is it about bass that sends chills to our soul and gives music so much power? We as humans are deeply rooted to rhythm before we're even born. According to cognitive science Karen Strum's world of Rutgers University, once the hearing part of the brain starts to function, a fetus hears mostly low frequency sounds, like its mother's heartbeat and the rhythm of her voice. Higher frequency tones that come from outside the mother's body are drowned out. Scientists think that these low frequency sounds may be a crucial factor in a baby's early language acquisition. After birth, this connection continues and is apparent everywhere. Bass in music has a unique impact on the human body. It can even cause changes in our adrenaline and heart rate. When listening to music, our brains track the rhythm through a process called neural entrainment. Upper and lower bass notes range from about 32 to 512 hertz, and these low frequency sounds direct our interpretation of the beat. And if you're wondering why the beat is so important to a song, ask yourself, why are bones so important to the body? They're the structure. The bass line is the foundation that the melody hangs upon. Last year, Canada McMaster's Institute for Music in the Mind conducted a study to test the human brain's response to high and low frequency tones in music. High and low pitch piano notes were played simultaneously for 35 participants. Occasionally, one of the two notes was played 50 milliseconds off beat. When participants detected these breaks in the rhythm, it triggered spikes in their brain response, otherwise known as mismatched negativity. These spikes happen much more often with changes in the low notes. The study found that the human brain is a lot more sensitive to timing deviations and lower frequency tones, which is why we're more accepting of fluctuations within a song's melody and more easily confused by fluctuations within a song's bass line. The director of this institute, neuroscientist Dr. Laurel Trainor, concludes that virtually all people will respond more to the beat when it's carried by lower pitch instruments. Although these studies are fairly new, musical composers have played off of people's organic response to bass since the stone age. So next time the beat drops, consider the fact that you are reacting to a connection with sound that you've had before you were born. It's something that connects us all, and it's all about the bass.