In my last post, I talked about some of the ways that bottlefeeding is a different experience for babies than breastfeeding, and I speculated freely on the possible outcomes of the two kinds of experience. Here are some more differences and POSSIBLE results-still unknown in terms of systematic investigation.
To do a good job of feeding a baby by any method, an adult has to pay attention to the baby's communications: "That's enough!" or "I can't get any milk!" or "My nose is blocked!". This is one reason why propping a baby's bottle is unwise and generally prohibited in infant day care settings. But breast-fed babies also communicate another essential piece of information--- whether they are ready to switch from one breast to the other. (Nursing mothers usually give both breasts at any "meal", to help keep them producing the same amounts of milk.) A nursing mother really can't tell very well how much milk her baby has taken from the breast, although the breast is usually rather firm to the touch when full of milk and softer after the baby has finished. Anyway, as I mentioned in an earlier post, the baby's hunger or thirst may determine when it's time to switch breasts. Only the baby's cues-- letting go the nipple and fussing-- let the mother know when it's time to move from right breast to left breast or vice versa. Even so, the mother has to pay close attention in order to be sure that the baby has not let go for some reason other than wanting to switch. Of course, if the mother is nursing a toddler, the child may speak well enough to say what he or she wants, but few mothers in the United States nurse that long.
Breastfeeding mothers often do other things while they are nursing. They may talk on the phone, eat a sandwich or drink a cup of tea, or read to an older child. However, paying attention to the baby's cues is always an important part of the task, and if the mother is neglectful or distracted things will not go well. This means that nursing mothers and their babies have many important communicative interactions every day, and probably more of them than bottlefed babies, who do not generally switch from one side to the other. Does this improve their communicative skills with each other, or perhaps their confidence that each can make the other understand? Maybe it does, but the evidence would be very hard to establish.
2. Eye contact.
One of the most common myths about breastfeeding is that nursing mothers and their babies gaze into each other's eyes for long periods of time and that this creates emotional attachment. It's certainly true that older babies will look at the feeding person's face and explore it with their hands, poking a finger up your nose, for example. (It's not all romantic, this baby care.) But younger babies do not look around much, whether they are breast- or bottle-fed. They tend to be so hungry and eager to suck that they squeeze their eyes shut, turn red, and even sweat lightly as they go at their meal.
Depending on the mother's anatomy, breastfed babies may have some trouble looking at the mother's face while nursing. They generally have to turn the face toward the breast in order to take the nipple. (The bottle can be moved toward the baby's mouth, but the baby's mouth has to turn toward the breast.) If a mother has round, dome-like breasts, it's impossible to move the nipple more than a little bit, so looking up at the mother's eyes while nursing is hardly possible. A more cone-like breast may be a good deal more movable, and an older baby especially may be able to move the head around while keeping the nipple more or less in the mouth. So, whether the baby can look at the mother's face while suckling can depend entirely on the mother's individual figure.
If eye contact while nursing were so critical to development, it seems that we should be able to tell which mothers had which kinds of breasts by looking at the children's later personalities. In addition to that, we might well predict that bottlefed babies-- who can more easily look up at the caregiver-- should develop in ways that are superior to breastfed babies. Neither of these ideas has ever been tested, so we don't know whether such plausible connections would be supported by empirical evidence.
And... I haven't even mentioned biting yet. Now, there is a big difference between breastfed and bottle-fed babies, and one that deserves some discussion in the future.