Infant feeding

Type of psychology: Biological bases of human behavior; Clinical; Counseling; Cultural; Developmental; Family; Social

Infant feeding has a profound influence on human development and growth, and it is particularly important in the early stages of child development. Some areas that may be related to infant feeding include physical growth, behavioral development, social development, psychosocial development, intellectual development, and cognitive development. The interplay of infant feeding and attachment styles may have long-lasting effects, and potential disparities between breastfeeding and formula feeding may factor into individuals' developmental trajectories across psychological contexts.

Introduction

Soon after the birth of a child, the process of infant feeding plays a central role in his or her development and growth. The practice of infant feeding has been observed across an array of cultures, and records of breastfeeding date early as 2,000 BCE. Researchers Emily Stevens, Thelma Patrick, and Rita Pickler have suggested that around this time wet nurses, or a person who breastfeeds another person's child, began to be used for feeding children. Also, in Israel there are records of breastfeeding dating back to 2,000 BCE, where it was considered a religious obligation. Since this early era, what is understood about breastfeeding, or nursing, and its relatedness to human development has progressed, and the available alternatives to breastfeeding have been developed further. The most prominent alternative to breastfeeding is formula feeding, and this may be a method of infant feeding used by parents who may be unable to breastfeed or may not prefer to breastfeed their child. In addition, an infant may be fed by exclusively pumping, which is a type of breastfeeding in which the breastfeeding parent expresses breast milk to give to the child using a bottle, rather than nursing at the breast. Whether breastfed or formula-fed, it is important to discern that infant feeding plays a crucial function in children's earliest stages of development. Infant feeding relates to the physical growth, intellectual growth, and attachment style of the child, and the observed differences between infants who are breastfed and infants who are formula-fed vary across these different contexts.

Physical, Behavioral, Social, and Psychosocial Development

In terms of physical growth, infant feeding is critical because it directly relates to the infant's caloric intake, and more broadly it may be related to the infant's behavior and day-to-day functioning. Peter Wright has suggested that breastfeeding may minimize the risk of rapid weight gain as compared to formula feeding, and this may be due to the nature of the infant pacing their feeding during breastfeeding as opposed to the faster flow of bottle nipples, whether the infant is fed with formula or expressed breast milk. Many medical organizations have suggested that parents and caregivers who bottle-feed their infant should use low-flow nipples to prevent the infant from being fed too quickly. Behaviorally, infants may differ in their ability to breastfeed, and R. F. Drewett has suggested that low intake may be a result of a child's motor problem or a problem with the parent's production of breast milk.

Drewett highlighted the notion that the energy derived from infant feeding is largely used for expenditure and not actual physical growth. Infants' crying and sleeping patterns may be closely tied to feeding, and Drewett cited that breastfed infants are less likely to sleep through the night as compared to bottle-fed infants. Interestingly, Peter Wright argued that infant feeding is one of the earliest examples of the zone of proximal development (ZPD), a Vygotskian theory that emphasizes the importance of scaffolding and pursuing potentially challenging behaviors or tasks with the support of those who are better equipped. Additionally, ZPD as it is related to infant feeding may be influential of how the child begins to organize his or her world, and the interaction of infant cues and parent's responsiveness may be another integral part of this construct.

Intellectual and Cognitive Development

Somewhat controversially, it has been posited that intellectual and cognitive development differs for breastfed infants as compared to formula-fed infants. In a meta-analysis investigating breastfed infants and cognitive outcomes, James Anderson, Bryan Johnstone, and Daniel Remley found that across twenty studies infants who were breastfed had enhanced cognitive development as compared to those who were formula-fed, and these differences were seen through childhood and adolescence. Echoing these findings, Jean Golding, Imogen Rogers, and Pauline Emmett discussed findings that may detail an association between breastfed infants and mental abilities, specifically that breastfed infants may have higher IQs than infants who are formula-fed. Research conducted by Ruth Feldman and Arthur Eidelman found that low-birth-weight and premature infants who received an abundance of breast milk had better neurodevelopmental gains than those who did not receive a significant amount of breast milk. At six months old (corrected age) these premature infants had higher mental skills than premature infants who did not receive as much breast milk.

Ann Reynolds alludes to research which has suggested breastfed children have better neurodevelopmental outcomes and higher IQs than infants who are formula-fed, warning that the causality of these findings must be scrutinized. Due to the inability to test these questions experimentally, confounding factors including socioeconomic status, parental IQ, bonding and attachment styles, maternal well-being, gestational age, and birth weight may be influencing these outcomes more than the differences arising between breastfeeding and formula-feeding infants. One major confounding question is whether the nutrients in breast milk themselves may be related to these beneficial gains or whether the physical closeness, tactile intimacy, and positional changes that occur during breastfeeding may be more influential on later intellectual and cognitive development. This aspect of infant feeding is an ongoing debate, and research continues to yield new findings that contribute to the understanding of how different approaches to infant feeding may be related to different intellectual and cognitive development.

Attachment

There is a storied history of psychoanalytic research interested in love and dependency as it relates to breastfeeding; however, most of this research has been discounted in favor of work pioneered by Mary Ainsworth and John Bowlby. As mentioned previously, infant feeding and caregivers' responsiveness to infant cues, especially when an infant is signaling for the need to be fed, may impact the development of the child's attachment style. Famed psychologist Mary Ainsworth argued that an infant's behavior, and the responsiveness of caregivers to these behavioral cues, may influence an infant's perception of control over environment. The attachment behaviors resulting from these types of feeding interactions may have long-lasting implications. Forming a close and intimate bond between mother and child is not unique to mothers who choose to nurse, as Marshall Klaus, John Kennell, and Phyllis Klaus have reasoned that physical and emotional closeness may be accomplished through bottle-feeding. This relationship is bidirectional, and as the infant's hunger is satiated, the mother may also feel personally fulfilled or satisfied for being able to provide for her child. John Bowlby reiterated this sentiment when expressing the importance of face-to-face time for the caregiver and infant which can occur during feeding. Although fathers or male caregivers may be unable to breastfeed their child, a similar intimacy between father and infant may be achieved through kangaroo care. This practice of having skin-to-skin contact with an infant may be beneficial for the well-being of infants, and this practice may be utilized during periods of feeding.

Problems with Feeding

Despite the positive characteristics and outcomes of infant feeding, there are some instances in which infant feeding may be problematic or harmful for the child or parent. Gillian Harris mentioned that negative feeding behaviors or refusal to feed may stem from problems within the interaction between caregiver and infant, or it may also be the result of a cognitive model in which infants' understanding of the feeding process may be inadequate. In the interaction model, an emphasis on improving the caregiver-infant relationship may improve these feeding problems. For the cognitive model, imitative processes may be especially salient for success, and classical conditioning could be one method to circumvent these issues. One other problem that may arise from infant feeding and the consumption of breast milk is the transmitting of teratogens. Some teratogens and harmful toxic agents, including mercury, may be passed through breast milk. Although the risk of mercury is low, breast milk may carry other teratogens that may be harmful to the infant's growth and development, and instances where the mother may be at risk for having breast milk containing teratogens should consult a professional about using formula in place of breastfeeding. Similarly, certain viral infections, including the human immunodeficiency virus (HIV), can be pass from the mother to child through breast milk.

Breastfeeding and challenges to breastfeeding may also impact the parent. Several studies from the 2020s showed that parents who struggle to breastfeed may have negative psychological impacts, including unhappiness, frustration, depression, and anxiousness. Other studies showed that there were links between the ability to breastfeed and postpartum depression, specifically wanting to breastfeed but struggling to do so could contribute to postpartum depression, while postpartum depression could contribute to a parent's decision to stop breastfeeding early.

Introduction of Solid Foods

The American Academy of Pediatrics (AAP), the UK National Health Service (NHS), and the World Health Organization (WHO) recommend that the introduction of solid foods to infants be delayed until the baby is about six months old. Prior to the introduction of solids, a baby should be able to sit in a high chair or feeding seat with good head control, show interest in food; be able to move food to the back of his or her mouth to swallow; and weight at least thirteen pounds or more.

At that age it is recommended to continue with breastfeeding or formula feeding in addition to introducing solid foods. Many parents begin the transition away from infant formula or breast milk around the age of one. In addition to solid food, some parents may introduce toddler formula or toddler milk as a nutritional supplement, however, pediatricians explain that while infant formula is highly regulated by the FDA to ensure nutritional levels, there are no regulations for nutrient levels for toddler formula.

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