Monday, March 26, 2012

Senses: Smell and Taste

In my last blog post I talked about three of the five senses. Today I am going to focus on the other two senses, Smell and Taste. 

Even before your baby was born, her senses were working. As early as week 25 of gestation, fetuses can hear their mothers' voices resonate from within the womb, and they hear voices on the outside: could be Daddy, Grandma, siblings, even Mom's coworkers. By four weeks old, your baby's sense of taste is well-developed; he's able to differentiate among what limited tastes he's been offered up to this point. 
And amazingly, your baby's nose develops right around the beginning of the second trimester. (Can you imagine how teeny it was then?) But at birth, it's not just that your baby can hear and smell that's impressive, but that he knows one person's voice and scent from another's—namely, yours. Here's how we know so much about infants' senses. 

  • Smell: To determine babies' abilities to discern among scents, researchers placed a pad on each side of the babies in the study. One held the scent of the mother and the other the scent of an unfamiliar person. They found that baby after baby turned her head toward the pad holding the mother's scent. 
We now know that Baby can literally sniff you out, and that he is comforted by familiar voices and smells. He knows, instinctively, "The person behind this voice and scent will do whatever it takes to meet my needs. Phew!"

  • Taste: Researchers presented newborn babies safe solutions that respectively tasted (even to adults) sweet, sour, and bitter. They did so in the first hours after the babies were born, before they had ever tasted milk from a bottle or from their mother's breasts. The newborns exhibited the same reactive facial expressions as a grown-up would:
  • When a tiny amount of the sweet solution was put on each baby's tongue, their facial expression looked like a smile. Plus, the newborns would lick their upper lip, making loud, happy, sucking sounds.
  • When tasting the sour solution, the babies pursed their lips, scrunched their noses, and blinked their eyes.
  • The response to the bitter taste was quick and dramatic: Upon it touching their tongues, the infants would retch or spit, clearly rejecting it. (Interestingly, it appears that nature equipped babies with this dramatic response to bitter tastes as a survival technique. By welcoming the sweet taste of their mother's milk (or formula), a baby grows and thrives. Conversely, by naturally rejecting anything that tastes bitter, they're more apt to survive—as nothing bitter will benefit their heath and development at this young age and actually could be poisonous. Sour tastes don't evoke quite the same rejection as bitter ones, but those pursed lips indicate that Baby wants to keep that taste away from her tongue.)
From these three distinct resulting expressions, researchers surmised that babies from birth arrive equipped to distinguish sweet, sour, and bitter tastes. 
Information found here

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