All these while, I've only been talking and talking based on my experience and what I've read before. To those who prefer more professional explanations and advise, this is directly extracted from www.askdrsears.com
1. Sling babies cry less. Parents in my practice commonly report, "As long as I wear her, she's content!" Parents of fussy babies who try babywearing relate that their babies seem to forget to fuss. This is more than just my own impression. In 1986, a team of pediatricians in Montreal reported on a study of ninety-nine mother-infant pairs. The first group of parents were provided with a baby carrier and assigned to carry their babies for at least three extra hours a day. They were encouraged to carry their infants throughout the day, regardless of the state of the infant, not just in response to crying or fussing. In the control, or noncarried group, parents were not given any specific instructions about carrying. After six weeks, the infants who received supplemental carrying cried and fussed 43 percent less than the noncarried group.
Anthropologists who travel throughout the world studying infant-care practices in other cultures agree that infants in babywearing cultures cry much less. In Western culture we measure a baby's crying in hours, but in other cultures, crying is measured in minutes. We have been led to believe that it is "normal" for babies to cry a lot, but in other cultures this is not accepted as the norm. In these cultures, babies are normally "up" in arms and are put down only to sleep – next to the mother. When the parent must attend to her own needs, the baby is in someone else's arms.
2. Sling babies learn more. If infants spend less time crying and fussing, what do they do with the free time? They learn! Sling babies spend more time in the state of quiet alertness . This is the behavioral state in which an infant is most content and best able to interact with his environment. It may be called the optimal state of learning for a baby. Researchers have also reported that carried babies show enhanced visual and auditory alertness.
The behavioral state of quiet alertness also gives parents a better opportunity to interact with their baby. Notice how mother and baby position their faces in order to achieve this optimal visually interactive plane. The human face, especially in this position, is a potent stimulator for interpersonal bonding. In the kangaroo carry, baby has a 180-degree view of her environment and is able to scan her world. She learns to choose, picking out what she wishes to look at and shutting out what she doesn't. This ability to make choices enhances learning. A sling baby learns a lot in the arms of a busy caregiver.
3. Sling babies are more organized. It's easier to understand babywearing when you think of a baby's gestation as lasting eighteen months – nine months inside the womb and at least nine more months outside. The womb environment automatically regulates baby's systems. Birth temporarily disrupts this organization. The more quickly, however, baby gets outside help with organizing these systems, the more easily he adapts to the puzzle of life outside the womb. By extending the womb experience, the babywearing mother (and father) provides an external regulating system that balances the irregular and disorganized tendencies of the baby. Picture how these regulating systems work. Mother's rhythmic walk, for example, (which baby has been feeling for nine months) reminds baby of the womb experience. This familiar rhythm, imprinted on baby's mind in the womb, now reappears in the "outside womb" and calms baby. As baby places her ear against her mother's chest, mother's heartbeat, beautifully regular and familiar, reminds baby of the sounds of the womb. As another biological regulator, baby senses mother's rhythmic breathing while worn tummy- to-tummy, chest-to-chest. Simply stated, regular parental rhythms have a balancing effect on the infant's irregular rhythms. Babywearing "reminds" the baby of and continues the motion and balance he enjoyed in the womb.
SLING TIP:The womb lasts eighteen months: Nine months inside mother, and nine months outside.
What may happen if the baby spends most of his time lying horizontally in a crib, attended to only for feeding and comforting, and then again separated from mother? A newborn has an inherent urge to become organized, to fit into his or her new environment. If left to his own resources, without the regulating presence of the mother, the infant may develop disorganized patterns of behavior: colicky cries, jerky movements, disorganized self-rocking behaviors, anxious thumb sucking, irregular breathing, and disturbed sleep. The infant, who is forced to self-calm, wastes valuable energy he could have used to grow and develop.
While there is a variety of child-rearing theories, attachment researchers all agree on one thing: In order for a baby's emotional, intellectual, and physiological systems to function optimally, the continued presence of the mother, as during babywearing, is a necessary regulatory influence.
4. Sling babies get "humanized" earlier. Another reason that babywearing enhances learning is that baby is intimately involved in the caregiver's world. Baby sees what mother or father sees, hears what they hear, and in some ways feels what they feel. Carried babies become more aware of their parents' faces, walking rhythms, and scents. Baby becomes aware of, and learns from, all the subtle facial expressions, body language, voice inflections and tones, breathing patterns, and emotions of the caregiver. A parent will relate to the baby a lot more often, because baby is sitting right under her nose. Proximity increases interaction, and baby can constantly be learning how to be human. Carried babies are intimately involved in their parents' world because they participate in what mother and father are doing. A baby worn while a parent washes dishes, for example, hears, smells, sees, and experiences in depth the adult world. He is more exposed to and involved in what is going on around him. Baby learns much in the arms of a busy person.
5. Sling babies are smarter. Environmental experiences stimulate nerves to branch out and connect with other nerves, which helps the brain grow and develop. Babywearing helps the infant's developing brain make the right connections. Because baby is intimately involved in the mother and father's world, she is exposed to, and participates in, the environmental stimuli that mother selects and is protected from those stimuli that bombard or overload her developing nervous system. She so intimately participates in what mother is doing that her developing brain stores a myriad of experiences, called patterns of behavior. These experiences can be thought of as thousands of tiny short-run movies that are filed in the infant's neurological library to be rerun when baby is exposed to a similar situation that reminds her of the making of the original "movie." For example, mothers often tell me, "As soon as I pick up the sling and put it on, my baby lights up and raises his arms as if in anticipation that he will soon be in my arms and in my world."
I have noticed that sling babies seem more attentive, clicking into adult conversations as if they were part of it. Babywearing enhances speech development. Because baby is up at voice and eye level, he is more involved in conversations. He learns a valuable speech lesson – the ability to listen.
Normal ambient sounds, such as the noises of daily activities, may either have learning value for the infant or disturb him. If baby is alone, sounds may frighten him. If baby is worn, these sounds have learning value. The mother filters out what she perceives as unsuitable for the baby and gives the infant an "It's okay" feeling when he is exposed to unfamiliar sounds and experiences.