My friend entrusted me with the privilege of holding her precious, four-day-old daughter. Not long after I took the baby into my arms, she started to fuss. I hugged her closer, my cheek pressed against her head, and began to sway and hum in a gentle rhythm to soothe her. Despite these earnest attempts, and my decade and a half of parenting experience, I couldn’t pacify her. She became increasingly upset until I placed her back into the crook of her mother’s eager arm. Peace washed over her almost instantaneously; her cries subsided and her newborn frame relaxed into the…