We were coming back from a wedding one night when my then-3-month-old baby started crying—big, loud howls that made it nearly impossible for me to focus on driving. I just wanted to fix it. Now.
Seeing me squirm in my seat and throw panicky glances into the rearview mirror, my brother-in-law astutely pointed out, "I bet you'd tear someone's arm off right now if it meant you could turn around and take care of him." Which sounded like a totally fair deal to me at the time.
Mama bear instincts? Hmm, maybe—but as researchers have recently discovered, there may be something even more primal at play when we hear a baby cry. That's because the very specific sound qualities of screaming set off the amygdala, or the region of the brain that generates a fear response. (Alarm clocks and car alarms also trigger it.) This helps explain our very physical response to baby's fussing: racing heartbeat, rising blood pressure, twinges of panic or discomfort.
To reach that conclusion, researchers first analyzed a database of recorded screams to pinpoint what exactly sets that sound apart from the rest (#worstjobever). The answer: a proper yell can change loudness up to 100 times each second, compared to the average four or five changes per second that occur when someone is talking. Then researchers hooked up volunteers to a functional MRI and mapped their brain activity as they listened to a variety of sounds, including screams. That's when they discovered the connection with the amygdala.
The findings were published Thursday in Cell Biology.
Of course, the question is, does knowing all of this make hearing babies cry any easier? Nah, probably not—but at least it can help explain your reaction to it.
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