Babies have a strong connection to sound -- especially sounds from their parents. You may have seen this video of a 2-year-old deaf boy squealing with bliss when he heard his mother's voice for the first time. These girls have clearly heard guitars before (they've got a dance routine down), their similar reaction never fails to be cute.
Watch out, Dad; you might have groupies on your hands.
Prachi Gupta is an Assistant News Editor for Salon, focusing on pop culture. Follow her on Twitter at @prachigu or email her at firstname.lastname@example.org.