The Newborn Infant

A healthy newborn is ready and able to continue the developmental saga in a new environment. The baby begins interacting with that environment right away, exploring and learning about newfound physical and social entities. Newborns’ exploration of this uncharted territory is very much influenced by their state of arousal.

State of Arousal

FIGURE 2.20 Newborn states This figure shows the average proportion of time, in a 24-hour day, that Western newborns spend in each of the six states of arousal. There are substantial individual and cultural differences in how much time babies spend in the different states.

state level of arousal and engagement in the environment, ranging from deep sleep to intense activity

State refers to a continuum of arousal, ranging from deep sleep to intense activity. As you well know, your state dramatically affects your interaction with the environment—with what you notice, do, learn, and think about. It also affects the ability of others to interact with you. State strongly mediates how young infants experience the world around them.

Figure 2.20 depicts the average amount of time in a 24-hour period that Western newborns typically spend in each of six states, ranging from quiet sleep to crying. Within this general pattern, however, there is a great deal of individual variation. Some infants cry relatively rarely, whereas others cry for hours every day; some babies sleep much more, and others much less, than the 16-hour average shown in the figure. Some infants spend more than the average of 2½ hours in the awake-alert state, in which they are fairly inactive but attentive to the environment. To appreciate how these differences might affect parent–infant interactions, imagine yourself as the parent of a newborn who cries more than the average, sleeps little, and spends less time in the awake-alert state. Now imagine yourself with a baby who cries relatively little, sleeps well, and spends an above-average amount of time quietly attending to you and the rest of his or her environment (see Figure 2.21). Clearly, you would have many more opportunities for pleasurable interactions with the second newborn.

FIGURE 2.21 Quiet-alert state The parents of this quiet-alert newborn have a good chance of having a pleasurable interaction with the baby.
KIDSTOCK/GETY IMAGES

The two newborn states that are of particular concern to parents—sleeping and crying—have both been studied extensively.

Sleep

Figure 2.22 summarizes several important facts about sleep and its development, two of which are of particular importance. First, “sleeping like a baby” means, in part, sleeping a lot; on average, newborns sleep twice as much as young adults do. Total sleep time declines regularly during childhood and continues to decrease, although more slowly, throughout life.

FIGURE 2.22 Total sleep and proportion of REM and non-REM sleep across the life span Newborns average a total of 16 hours of sleep, roughly half of it in REM sleep. The total amount of sleep declines sharply throughout early childhood and continues to decline much more slowly throughout life. From adolescence on, REM sleep constitutes only about 20% of total sleep time. (Adapted from Roffwarg et al., 1966, and from a later revision by these authors)

rapid eye movement (REM) sleep an active sleep state characterized by quick, jerky eye movements under closed lids and associated with dreaming in adults

Second, the pattern of two different sleep states—REM sleep and non-REM sleep—changes dramatically with age. Rapid eye movement (REM) sleep is an active sleep state that is associated with dreaming in adults and is characterized by quick, jerky eye movements under closed lids; a distinctive pattern of brain activity; body movements; and irregular heart rate and breathing. Non-REM sleep, in contrast, is a quiet sleep state characterized by the absence of motor activity or eye movements and more regular, slow brain waves, breathing, and heart rate. As you can see in Figure 2.22, REM sleep constitutes fully 50% of a newborn’s total sleep time. The proportion of REM sleep declines quite rapidly to only 20% by 3 or 4 years of age and remains low for the rest of life.

non-REM sleep a quiet or deep sleep state characterized by the absence of motor activity or eye movements and more regular, slow brain waves, breathing, and heart rate

Why do infants spend so much time in REM sleep? Some researchers believe that it helps develop the infant’s visual system. The normal development of the human visual system, including the visual area of the brain, depends on visual stimulation, but relatively little visual stimulation is experienced in the womb (particularly in contrast to fetal auditory stimulation, which, as you will see in the next section, is extensive). In addition, the fact that newborns spend so much time asleep means that they do not have much opportunity to amass waking visual experience. The high level of internally generated brain activity that occurs during REM sleep may help to make up for the natural deprivation of visual stimulation, facilitating the early development of the visual system in both fetus and newborn (Roffwarg, Muzio, & Dement, 1966). This theory is supported by a study showing that newborns who had been given a high level of extra visual stimulation during the day spent less of their subsequent sleep time in REM sleep than did infants exposed to lower levels of visual stimulation (Boismier, 1977).

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Another distinctive feature of sleep in the newborn period is that napping newborns may actually be learning while asleep. In one study that investigated this possibility, infants were exposed to recordings of Finnish vowel sounds while they slumbered in the newborn nursery. When tested in the morning, their brain activity revealed that they recognized the sounds they had heard while asleep (Cheour et al., 2002). In a recent study, researchers trained sleeping neonates to make an eye-movement response to a puff of air toward their closed eyelids (Fifer et al., 2010). During the training phase, the newborns were repeatedly presented with a tone just before each puff of air. Given this experience, they quickly learned to expect the air puff after the tone, as evidenced by their making an eye movement in response to the tone alone. Newborns seem able to learn in their sleep because their slumbering brains do not become disconnected from external stimulation to the same extent that the brains of older individuals do.

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Most American parents want to avoid the 2 a.m. fate of this young father. They regard their baby’s sleeping through the night as a developmental triumph—the sooner, the better.
BUBBLES PHOTOLIBRARY/ALAMY

Another difference between the sleep of young infants and older individuals (not reflected in Figure 2.22) is in sleep–wake cycles. Newborns generally cycle between sleep and waking states several times in a 24-hour period, sleeping slightly more at night than during the day (Whitney & Thoman, 1994). Although newborns are likely to be awake during part of their parents’ normal sleep time, they gradually develop the more mature pattern of sleeping through the night.

The age at which infants’ sleep patterns come to match those of adults depends very much on cultural practices and pressures. For example, many infants in the United States sleep through the night by around 4 months of age—a development actively encouraged by their parents. Indeed, tired parents employ many different strategies to get their infants to sleep through the night—from adopting elaborate, often extended bedtime rituals intended to lull the baby into dreamland to gritting their teeth and letting the baby cry himself or herself to sleep. (Note: one little-known but particularly useful strategy for encouraging longer periods of nighttime sleeping is exposing the infant to bright sunlight during the day [Harrison, 2004].)

In contrast with U.S. parents, Kipsigis parents in rural Kenya are relatively unconcerned about their infants’ sleep patterns. Kipsigis babies are almost always with their mothers. During the day, infants are often carried on their mother’s back as she goes about her daily activities, and at night they sleep with her and are allowed to nurse whenever they awaken. As a consequence, these babies distribute their sleeping throughout the night and day for several months (Harkness & Super, 1995; Super & Harkness, 1986). Thus, cultures vary not only in terms of where babies sleep, as you learned in Chapter 1, but also in terms of how strongly parents attempt to influence when their babies sleep.

Crying

How do you feel when you hear a baby cry? We imagine that, like most people, you find the sound of a crying infant extremely unpleasant. Why is an infant’s cry so aversive?

From an evolutionary point of view, adults’ aversion to infants’ crying could have adaptive value. Infants cry for many reasons—including illness, pain, and hunger—that require the attention of caregivers. Parents are likely to attempt to quiet their crying infant by taking care of the infant’s needs, thereby promoting the infant’s survival. This fact has led some researchers to suggest that in times of hardship, such as famine, cranky babies are more likely to survive than are placid ones, possibly because their distress elicits adult attention and they consequently get more than their share of scarce food resources (DeVries, 1984).

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Parents, especially first-timers, are often puzzled and anxious about why their baby is crying. Indeed, one of the most frequent complaints pediatricians hear from parents concerns crying that the parents think is excessive but is actually common (Barr, 1998; Harkness et al., 1996). With experience, parents become better at interpreting their infants’ crying, identifying characteristics of the cry itself (a sharp, piercing cry usually signals pain, for example) and considering the context (such as when the infant’s last feeding was) (Green, Jones, & Gustafson, 1987).

Do all newborns’ cries sound alike? Parents certainly do not think so. In fact, within the first week after birth, mothers are able to distinguish their own newborn’s cries from those of other infants (e.g., Cismaresco & Montagner, 1990). Newborns’ cries are also differentially shaped by the sounds of the language in their environment. A recent study that compared the crying patterns of French and German newborns found that the infants’ cries followed different acoustic patterns that mimicked the pitch patterns in their home language (Mampe et al., 2009).

After the newborn period, crying behavior typically increases, cresting at about 6 weeks of age, and then declines to about an hour a day for the rest of the first year (St James-Roberts & Halil, 1991). On a daily basis, the peak time for crying is late afternoon or evening, which can be quite disappointing to parents looking forward to interacting with their baby at the end of the workday. Increased crying late in the day may be due to an accumulation of excess stimulation during the daytime hours.

The nature of crying and the reasons for it change with development. Early on, crying reflects discomfort from pain, hunger, cold, or overstimulation, although, from the beginning, infants also cry from frustration (Lewis, Alessandri, & Sullivan, 1990; Stenberg, Campos, & Emde, 1983). Over time, crying becomes more communicative, often seeming geared to “tell” caregivers something and to get them to respond (Gustafson & Green, 1988).

Soothing What are the best ways to console a crying baby? Most of the traditional standbys—rocking, singing lullabies, holding the baby up to the shoulder, giving the baby a pacifier—work reasonably well (R. Campos, 1989; Korner & Thoman, 1970). Many effective soothing techniques involve moderately intense and continuous or repetitive stimulation. The combination of holding, rocking, and talking or singing relieves an infant’s distress better than any one of them alone (Jahromi, Putnam, & Stifter, 2004).

swaddling a soothing technique, used in many cultures, that involves wrapping a baby tightly in cloths or a blanket

One very common soothing technique is swaddling, which involves wrapping a young baby tightly in cloths or a blanket, thereby restricting limb movement. The tight wrapping provides a constant high level of tactile stimulation and warmth. This technique is practiced in cultures as diverse and widespread as those of the Navajo and Hopi in the American Southwest (Chisholm, 1983), the Quechua in Peru (Tronick, Thomas, & Daltabuit, 1994), and rural villagers in Turkey (Delaney, 2000). Another traditional approach, distracting an upset infant with interesting objects or events, can also have a soothing effect, but the distress often resumes as soon as the interesting stimulus is removed (Harman, Rothbart, & Posner, 1997).

Carrying infants close to the parent’s body results in less crying. Many Western parents are now emulating the traditional carrying methods of other societies around the world.
ANDREY BURKOV/DREAMSTIME.COM

Touch can also have a soothing effect on infants. In interactions with an adult, infants fuss and cry less, and they smile and vocalize more, if the adult pats, rubs, or strokes them (Field et al., 1996; Peláez-Nogueras et al., 1996; Stack & Arnold, 1998; Stack & Muir, 1992). Carrying young infants, as is routinely done in many societies around the world, reduces the amount of crying that they do (Hunziker & Barr, 1986). In fact, a recent study found that crying infants showed sharper decreases in heart rate, physical movement, and crying when carried about by their mother than when held in her lap. Similar quieting responses are seen in maternal carrying in other species (think of how still lion cubs become when carried by their mother) and are conjectured to be innate cooperative mechanisms that facilitate the mother’s carrying efforts (Esposito et al., 2013).

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In other laboratory studies, placing a small drop of something sweet on a distressed newborn’s tongue has been shown to have a dramatic calming effect (Barr et al., 1994; Blass & Camp, 2003; Smith & Blass, 1996). A taste of sucrose has an equally dramatic effect on pain sensitivity; newborn boys who are given a sweetened pacifier to suck during circumcision cry much less than babies who do not receive this simple intervention (Blass & Hoffmeyer, 1991).

Response to distress One question that often concerns parents is how to respond to their infant’s signals of distress. They wonder whether quick and consistent supportive responses will reward the infant for fussing and crying, and hence increase these behaviors, or will instead give the infant a sense of security that leads to less fussing and crying. An answer to this question comes from a longitudinal study that found that infants whose cries were ignored during the first 9 weeks actually cried less during the next 9 weeks (Hubbard & van IJzendoorn, 1991). Assessing the severity of the infant’s distress before responding may be the key factor. If a parent responds quickly to severe distress but delays responding to minor upset, the infant may learn to cope with less serious problems on his or her own and hence end up crying less overall.

colic excessive, inconsolable crying by a young infant for no apparent reason

Colic No matter how or how much their parents try to soothe them, some infants are prone to excessive, inconsolable crying for no apparent reason during the first few months of life, a condition referred to as colic. Not only do “colicky” babies cry a lot, but they also tend to have high-pitched, particularly unpleasant cries (Stifter, Bono, & Spinrad, 2003). The causes of colic are unknown, and may include allergic responses to their mothers’ diets (ingested via breast milk), formula intolerance, immature gut development, and/or excessive gassiness. Unfortunately, colic is not a rare condition: more than 1 in 10 young U.S. infants—and their parents—suffer from it. Fortunately, it typically ends by around 3 months of age and leaves no ill effects (Stifter & Braungart, 1992; St James-Roberts, Conroy, & Wilsher, 1998). One of the best things parents with a colicky infant can do is seek social support, which can provide relief from the stress, frustration, and sense of inadequacy and incompetence they may feel because they are unable to relieve their baby’s distress.

Negative Outcomes at Birth

Although most recognized pregnancies in an industrialized society result in the full-term birth of a healthy baby, sometimes the outcome is less positive. The worst result, obviously, is the death of an infant. A much more common negative outcome is low birth weight, which can have long-term consequences.

Infant Mortality

infant mortality death during the first year after birth

Infant mortality—death during the first year after birth—is now relatively rare in the industrialized world, thanks to decades of improvements in public health and general economic levels. In the United States, the 2010 infant mortality rate was 6.14 deaths per 1000 live births, the lowest in U.S. history (Miniño & Murphy, 2012).

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Although the U.S. infant mortality rate is at an all-time low in absolute terms, it is high compared with that of other industrialized nations. (Table 2.3 shows where the United States’ infant mortality rate stood relative to the rates of a selection of developed countries in 2008.) The relative ranking of the United States has generally gotten worse over the past several decades, because the infant mortality rates in many other countries have had a higher rate of improvement.


The rates of infant mortality are starkly different for subsets of the U.S. population. African American infants are more than twice as likely to die before their first birthday as European American infants are. Indeed, the infant mortality rate for African Americans is similar to the rates observed in many underdeveloped countries.

Why do so many babies die in the United States—the richest country in the world? Why are African American infants’ chances of survival so much poorer than those of White American infants? There are many reasons, most having to do with poverty. For example, many low-income mothers-to-be, including a disproportionate number of African Americans, have no health insurance and thus limited access to good medical and prenatal care (Cohen & Martinez, 2006). In contrast, the countries that rank above the United States with respect to infant mortality usually provide government-sponsored health care that guarantees prenatal care at low or minimal cost.

In less developed countries, especially those suffering from a breakdown in social organization due to war, famine, major epidemics, or persistent extreme poverty, the infant mortality rates can be staggering. In countries like Afghanistan, Mali, and Somalia, for example, roughly one of every 10 infants dies before age 1 (Central Intelligence Agency, 2012).

Afghanistan has one of the highest infant mortality rates in the world. Among the causes are extreme poverty, poor nutrition, and poor sanitation. The great majority of the population lacks access to clean water, leading to a great many infant deaths related to dysentery, severe diarrhea, and other illnesses.
AP PHOTO/EMILIO MORENATTI

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Low Birth Weight

Video: Low Birthweight in India

low birth weight (LBW) a birth weight of less than 5½ pounds (2500 grams)

The average newborn in the United States weighs 7½ pounds (most are between 5½ and 10 pounds). Infants who weigh less than 5½ pounds (2500 grams) at birth are considered to be of low birth weight (LBW). Some LBW infants are premature, or preterm; that is, they are born at 35 weeks after conception or earlier, instead of the normal term of 38 weeks. Other LBW infants are referred to as small for gestational age: they may be either preterm or full-term, but they weigh substantially less than is normal for their gestational age, which is based on weeks since conception.

premature any child born at 35 weeks after conception or earlier (as opposed to the normal term of 38 weeks)

Slightly more than 8% of all U.S. newborns are of LBW (Martin et al., 2012). The rate for African American LBW newborns is nearly twice as high (13.6%), and approaches the LBW rate observed in developing countries (16.5%) (United Nations Children’s Fund and World Health Organization, 2004). As a group, LBW newborns have a heightened level of medical complications, as well as higher rates of neurosensory deficits, more frequent illness, lower IQ scores, and lower educational achievement. Very LBW babies (those weighing less than 1500 grams, or 3.3 pounds) are particularly vulnerable; these infants accounted for 1.45% of live births in the United States in 2009 (Martin et al., 2011).

These newborns were among 5503 triplet births in the United States in 2010. That year, there were also 313 quadruplet births and 37 quintuplet and other higher-order births.
INSPIRESTOCK INC./ALAMY

small for gestational age babies who weigh substantially less than is normal for whatever their gestational age

There are numerous causes of LBW and prematurity, including many of the infant-mortality risk factors discussed earlier. Another cause is the skyrocketing rate of twin, triplet, and other multiple births as a result of the development of increasingly successful treatments for infertility. (The use of fertility drugs typically results in multiple eggs being released during ovulation; the use of in vitro fertilization [IVF] usually involves the placement of multiple laboratory-fertilized embryos in the uterus.) In 1980, 1 in every 53 infants born in the United States was a twin; in 2009, 1 in every 30 infants was a twin (Martin, Hamilton, & Osterman, 2012). The numbers for higher-order births (triplets and up) have also increased dramatically in recent years. This is a concern because the rates of LBW among multiples are quite high: 56% for twins and higher than 90% for triplets and above (Martin et al., 2011). (Box 2.5 discusses some of the challenges faced by parents of LBW infants.)

Long-term outcomes What outcome can be expected for LBW newborns who survive? This question becomes increasingly important as newborns of ever lower birth weights—some as low as 800 grams (about 1.76 pounds)—are kept alive by modern medical technology. The answer includes both bad news and good news.

The bad news is that, as a group, children who were LBW infants have a higher incidence of developmental problems: the lower their birth weight, the more likely they are to have persistent difficulties (e.g., Muraskas, Hasson, & Besinger, 2004). They suffer from somewhat higher levels of hearing, language, and cognitive impairments. In preschool and elementary school, they are more likely to be distractible and hyperactive and to have learning disabilities. This group is also more likely to experience a variety of social problems, including poor peer and parent–child relations (Landry et al., 1990). Finally, adolescents who were LBW babies are less likely than their siblings to complete high school (Conley & Bennett, 2002). This result holds even within twin pairs; the twin with higher birth weight is more likely to complete high school than is his or her smaller co-twin (Black et al., 2007).

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The good news is that the majority of LBW children turn out quite well. The negative effects of their birth status gradually diminish, with children who were slightly to moderately underweight as newborns generally ending up within the normal range on most developmental measures (Kopp & Kaler, 1989; Liaw & Brooks-Gunn, 1993; Meisels & Plunkett, 1988; Vohr & Garcia-Coll, 1988). Figure 2.23 depicts a particularly striking example of this fact (Muraskas et al., 2004). Indeed, one recent follow-up study of extremely LBW infants (<1000 grams) found that by 18 to 22 months of age, 16% were unimpaired and 22% were only mildly impaired (Gargus et al., 2009).

FIGURE 2.23 Small miracles Shown here is (a) one of the smallest newborns ever to survive and (b) the same child at 14 years of age. Born in 1989 after just 27 weeks of gestation, Madeline weighed a mere 9.9 ounces—approximately the equivalent of three bars of soap. Extremely LBW infants tend to suffer serious disabilities, but Madeline is remarkably healthy, other than being a bit small for her age and having asthma. She entered high school as an honor student and enjoys playing her violin and rollerblading.
AP PHOTO/A. HAYASHI/LOYOLA UNIVERSITY HEALTH SYSTEM

Intervention programs What can be done to help an LBW infant overcome his or her poor start in life? A variety of intervention programs for LBW newborns offer a prime example of our theme about the role of research in improving the welfare of children. In many of them, parents are active participants, a marked change from past practice. Hospitals formerly did not allow parents to have any contact with their LBW infants, mainly because of fear of infection. Parents are now encouraged to have as much physical contact and social interaction with their hospitalized infant as the baby’s condition allows.

One widely implemented intervention for hospitalized newborns is based on the idea that being touched—cuddled, caressed, and carried—is a vital part of a newborn’s life. Many LBW infants experience little stimulation of this kind because of the precautions that must be taken with them, including keeping them in special isolettes, hooked up to various life-support machines. To compensate for this lack of everyday touching experience, Field and her colleagues (Field, 2001; Field, Hernandez-Reif, & Freedman, 2004) developed a special therapy that involves massaging LBW babies and flexing their arms and legs (Figure 2.24). LBW babies who receive this therapy are more active and alert and gain weight faster than those who are not massaged. As a consequence, they get to go home earlier. Recent results also suggest that having parents sing to their LBW newborns during their stay in the hospital similarly improves the newborns’ health, while also calming parents’ fears (Loewy et al., 2013).

FIGURE 2.24 Infant massage Everybody enjoys a good massage, but hospitalized newborns particularly benefit from extra touching.
PROFIMEDIA.CZ A.S./ALAMY

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Box 2.5: applications: PARENTING A LOW-BIRTH-WEIGHT BABY

Parenthood is challenging under the best of circumstances, but it is especially so for the parents of a preterm or LBW baby. First, they have to accept their disappointment over the fact that they do not have the perfect baby they had hoped for, and they may also have to cope with feelings of guilt (“What did I do wrong?”), inadequacy (“How can I possibly take care of such a tiny, fragile baby?”), and fear (“Will my baby survive?”). In addition, caring for an LBW baby can be especially time-consuming and stressful and, if the infant requires extended treatment, very expensive.

While all new parents have a great deal to learn about caring for their infants, parents of an LBW baby face special challenges from the outset. In the hospital, they need to learn how to interact successfully with their fragile baby, who may be confined to an isolette and hooked up to life-support equipment. When their infant comes home, they may have to cope with a baby who is fairly passive and unresponsive, while being careful not to overstimulate the infant in an effort to elicit some response (Brazelton, Nugent, & Lester, 1987; Patteson & Barnard, 1990). LBW infants also tend to be fussier than the average baby and more difficult to soothe when they become upset (Greene, Fox, & Lewis, 1983). To compound matters, they often have a high-pitched cry that is particularly unpleasant (Lester et al., 1989).

Another problem for parents is the fact that LBW infants have more trouble falling asleep, waking up, and staying alert than do infants of normal birth weight, and their feeding schedules are less regular (DiVitto & Goldberg, 1979; Meisels & Plunkett, 1988). Thus, it takes longer for the baby to get on a predictable schedule, making the parents’ lives more hectic.

Parents of a preterm infant also need to understand that their baby’s early development will not follow the same timetable as a full-term infant’s: developmental milestones will be delayed, often linked more tightly to gestational age at birth than to chronological age after birth. For example, their infant will not begin to smile at them at around 6 weeks of age, the time when full-term infants usually reach this milestone. Instead, they may have to wait several more weeks for their baby to look them in the eye and break into a heart-melting smile. Thus, preterm infants are potentially more challenging to care for while being less rewarding to interact with. One consequence is that children who were born preterm are more likely to be victims of parental child abuse than are full-term infants (e.g., Spencer et al., 2006).

Parents of an LBW baby usually have to wait longer to experience the joy of their child’s first social smile.
THINKSTOCK/GETY IMAGES

One step that can be helpful to parents of an LBW or preterm infant is learning more about infant development. One intervention program trained mothers—in the hospital and after returning home—to interpret their preterm babies’ signals (Achenbach et al., 1990). When tested at age 7 years, their children showed significantly better cognitive skills than those of a comparison group of LBW children whose parents did not receive training.

In a more recent longitudinal study, researchers randomly assigned a group of mothers of preterm infants to either receive an intervention focused on increasing parental self-confidence and responsiveness or to be in a control group that received no intervention (Nordhov et al., 2012). At age 5, a comparison of behavioral outcomes for the children in each group (as rated by parents and preschool teachers) indicated that the children whose mothers experienced the intervention had fewer behavior problems than did the children whose mothers did not experience the intervention. This was particularly the case in the areas of aggressive behavior and attention deficits, which are often associated with preterm birth. This result is especially informative because the study’s randomized control design means that the findings cannot be readily explained by preexisting differences among the infants and their families.

In addition, any parent who is trying to deal with an LBW baby or an infant with other problems would do well to seek social support—from a spouse or partner, other family members, friends, or a formal support group. One of the best-documented phenomena in psychology is that we all cope better with virtually any life problem when we have support from other people. Indeed, one potentially important component of the successful intervention described in the preceding paragraph is that it included support sessions, in the hospital and during home visits, designed to encourage parents to talk about their experiences and express their feelings.

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Many intervention programs for LBW newborns extend beyond their hospital stay, some for several years (e.g., Ramey & Campbell, 1992). The potential of such interventions was highlighted by the Infant Health and Development Project (IHDP), which involved 985 children in eight major U.S. cities. This program was especially well designed. For one thing, the infants were randomly assigned to either the intervention group or the control group. For another, all the children were provided good health care, which ensured that this crucial factor could not affect the outcome of the research. The intervention lasted for 3 years and included an intensive early-childhood education program, as well as home visits that, among other things, encouraged the parents’ continued participation in the program.

Repeated assessments of the children in this study have consistently revealed a positive effect of intervention, at least for infants who weighed more than 2000 grams. At 3 years of age, the intervention group had an advantage of 14 IQ points over the control group, although the difference was larger for the LBW children who had been relatively heavier at birth—2000 to 2500 grams versus less than 2000 grams. In follow-ups at 5 and 8 years of age, the intervention group continued to show advantages, though these were limited to those participants who had weighed more than 2000 grams at birth. In the most recent assessment, when the participants were 18 years old, differences favoring the intervention group—better academic performance and fewer behavior problems—were still observed, but, again, only for those teenagers who had been the heavier LBW newborns (McCormick et al., 2006). The researchers concluded that their results provide support for early intervention to promote the development of at-risk LBW infants, but they also noted that such interventions are less likely to be successful with children who were extremely small newborns.

The IHDP story illustrates three important general points relevant to intervention efforts designed for high-risk infants. First, many intervention programs produce gains, but often those gains are relatively modest and diminish over time. Second, the success of any intervention depends on the initial health status of the infant. Like the IHDP, many programs for LBW babies have been most beneficial to those infants who are less tiny at birth. This fact is cause for concern, as modern medical technology makes it increasingly possible to save the lives of ever-smaller infants who have a high risk of permanent, serious impairment. The third point is the importance of cumulative risk: the more risks the infant endures, the lower the chances of a good outcome. Because this principle is so important for all aspects of development, we examine it in greater detail in the following section.

Multiple-Risk Model

FIGURE 2.25 Multiple risk factors Children who grow up in families with multiple risk factors are more likely to develop psychiatric disorders than are children from families with only one or two problematic characteristics (Rutter, 1979).

Risk factors tend to occur together. For example, a woman who is so addicted to alcohol, cocaine, or heroin that she continues to abuse the substance even though she is pregnant is likely to be under a great deal of stress and unlikely to eat well, take vitamins, earn a good income, seek prenatal care, have a strong social support network, or take good care of herself in other ways. Furthermore, whatever the cumulative effects of these prenatal risk factors, they will likely be compounded after birth by the mother’s continuation of her unhealthy lifestyle and by her resulting inability to provide good care for her child (e.g., Weston et al., 1989).

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As you will see repeatedly throughout this book, a negative developmental outcome—whether in terms of prenatal or later development—is more likely when there are multiple risk factors. In a classic demonstration of this fact, Michael Rutter (1979) reported a heightened incidence of psychiatric problems among English children growing up in families with four or more risk factors (including marital distress, low SES, paternal criminality, and maternal psychiatric disorder) (Figure 2.25). Thus, the likelihood of developing a disorder is slightly elevated for the child of parents who fight a lot; but if the child’s family is also poor, the father engages in criminal behavior, and the mother suffers from emotional problems, the child’s risk is multiplied nearly tenfold. Similar risk patterns have been reported for IQ (Sameroff et al., 1993) and social-emotional competence (Sameroff et al., 1987).

Poverty as a Developmental Hazard

Because it is such an important point, we cannot emphasize enough that the existence of multiple risks is strongly related to SES. Consider some of the factors we have discussed that are known to be dangerous for fetal development: inadequate prenatal care, poor nutrition, illness, emotional stress, cigarette smoking, drug abuse, and exposure to environmental and occupational hazards. All these factors are more likely to be experienced by a woman living below the poverty line than by a middle-class woman. It is no wonder, then, that on the whole, the outcome of pregnancy is less positive for infants of lower-SES parents than for babies born to middle-class parents (Kopp, 1990; Minde, 1993; Sameroff, 1986). Nor should it be surprising that among LBW infants, the eventual developmental outcome is poorer for those in lower-SES families (Drillien, 1964; Gross et al., 1997; Kalmár, 1996; Largo et al., 1989; Lee & Barratt, 1993; McCarton et al., 1997; Meisels & Plunkett, 1988).

An equally sad fact is that in many countries, minority families are overrepresented in the lowest SES levels. According to a study by the National Center for Children in Poverty, in 2011, 22% of all U.S. children lived in families whose income placed them below the poverty line ($22,350 for a family of four in that year). However, among African American and Hispanic children, the percent living in poverty was 39% and 34%, respectively (Addy, Engelhardt, & Skinner, 2013). Thus, their SES places many minority fetuses, newborns, and children at increased risk for developmental difficulties.

Risk and Resilience

developmental resilience successful development in spite of multiple and seemingly overwhelming developmental hazards

There are, of course, individuals who, faced with multiple and seemingly overwhelming developmental hazards, nevertheless do well. In studying such children, researchers employ the concept of developmental resilience (Garmezy, 1983; Masten, Best, & Garmezy, 1990; Sameroff, 1998). Resilient children—like those in the Kauai study discussed in Chapter 1—often have two factors in their favor: (1) certain personal characteristics, especially intelligence, responsiveness to others, and a sense of being capable of achieving their goals; and (2) responsive care from someone.

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In summary, development is highly complex, from the moment of conception to the moment of birth. As you will see throughout this book, that complexity continues over the ensuing years. Although early events and experiences can profoundly affect later development, developmental outcomes are never a foregone conclusion.

review:

The experience of newborn infants is mediated by internal states of arousal, ranging from deep sleep to intense crying, with large individual differences in the amount of time spent in the different states. Newborns spend roughly half their time asleep, but after early infancy, the amount of sleep declines steadily over many years. Researchers believe that the large proportion of sleep time that newborns spend in REM sleep is important for the development of the visual system and brain. Infants’ crying is a particularly salient form of behavior for parents, and it generally elicits attention and caretaking. Effective soothing techniques provide moderately intense, continuous, or repetitive stimulation. How parents respond to their young infant’s distress is related to later crying.

Negative outcomes of pregnancy are higher for minorities and for families living in poverty. The United States has higher rates of infant mortality than do many other developed nations. Just more than 8% of all infants born in the United States are LBW. Although most will suffer few lasting effects, the long-term outcome of extremely LBW babies is often problematic. Several large-scale intervention programs have successfully improved the outcome of LBW infants.

According to the multiple-risk model, the more risks that a fetus or child faces, the more likely the child is to suffer from a variety of developmental problems. Low SES is associated with many developmental hazards. Despite facing multiple risks, many children nevertheless show remarkable resiliency and thrive.