But while infants like it when anyone sings to them, researchers say they tend to focus more on their mom's voice, possibly because that's the one they heard in utero. This preference for the female voice may be one reason why babies are so responsive to the high-pitched tone that many adults instinctively use when talking to them. Budding Tastes Babies, even newborns, have a sweet tooth. Research suggests that infants may reject some bitter and very sour flavors but will suck longer and stronger and show a relaxed facial response when they're given sweet drinks. If your baby must undergo a painful procedure, such as a circumcision, ask your doctor if, along with any anesthesia, he can give your baby a pacifier dipped in sugar solution to help ease your child's discomfort.
Experts believe that infants' preference for sugar is a primitive survival mechanism.
Other research suggests that sweets stimulate production of endorphins, chemicals that activate the brain's pleasure-response system. An hours-old newborn can locate his mother's nipple by smell and can distinguish her scent from other mothers' within his first week of life. And babies as young as 2 weeks also learn other maternal odors, such as her perfume or shampoo, says Gary Beauchamp, Ph.D., director of the Monell Chemical Senses Center, in Philadelphia. That may be why older babies often prefer that their security objects remain unwashed. Similarly, even though babies are able to distinguish their mother's face from others at 1 month of age, they aren't soothed just by seeing their mom walk into the room until they're about 5 or 6 months old, when they begin to understand that her appearance means their needs will soon be met.