Week2
GEMENI80
04CH_Mossler_Child.pdf
4Birth and the Newborn
©Randy Faris/Corbis
Learning Objectives
After completing this module, you should be able to:
ሁ Describe various birth processes including the techniques used and the role of different kinds of professionals.
ሁ Explain the process of labor, including vaginal deliveries and cesarean sections. ሁ Identify appropriate markers used for assessing the newborn infant. ሁ Differentiate between preterm and low-birth-weight infants; identify potential consequences. ሁ Understand variability in infant care, including cultural differences and psychosocial and
nutritional issues. ሁ Summarize controversies regarding cosleeping, SIDS, and infant nutrition. ሁ Describe initial infant responses, including reflexes and perceptual abilities.
Section 4.1Variations in Birthing Practices
Prologue When my wife went into labor with our first-born child, we were in a parking lot ready to go into a home improvement store—neither of us remembers what we were going to buy. The first contraction was painful, so what did we do? We went to an electronics store 15 minutes away to buy a backup battery to make sure that we could record the events at the hospital! (The salesperson asked my wife when she was due. When she replied, “I just started labor,” we moved quickly to the front of the checkout line.) We then went home so that my wife could take a shower and I could call my 30 clients to let them know that my three-week break would be starting the next day. We left for the 40-minute ride to the hospital about 90 minutes after the first contraction, fully confident that my wife would not be delivering in our car on the freeway.
Labor is very different in reality than it often appears on television, where the amniotic sac (“the water”) breaks, there is a mind-numbing contraction, and 22 minutes later out pops a clean baby. It is more complicated than that, but at the same time it is usually a lot less chaotic than the media often depict. This module provides a more scientific view, while also maintaining an applied perspective. It begins with potential birthing options, the choices in birthing professionals, and the process of labor. Then, it discusses global issues that affect newborns and their parents, before examining the many built-in competencies that enable newborn infants to explore their world.
4.1 Variations in Birthing Practices In 1900, nearly every baby was born away from a hospital. By the beginning of the twenty- first century, the proportion of out-of-hospital births had dropped to below 1%. Not only have experience and technology changed the outcome of pregnancies, but birthing options have continued to evolve as well. In a recent 5-year span, the number of women in the United States who gave birth at home increased by over 20%. Though a substantial increase, this proportion still represents only 1.36% of all births. Trends may be changing, but nearly 99% of all U.S. births occur in hospitals, usually supervised by physicians (MacDorman, Declercq, & Mathews, 2011; MacDorman, Mathews, & Declercq, 2014).
This pattern is not the same throughout the world. For instance, the Netherlands has the high- est rate of at-home births in the developed world, at 23% (Brouwers et al., 2013). However, in contrast to the United States, at-home births declined steeply, by 35%, in the Netherlands during the decade that ended in 2010. In developing nations, where medical professionals are rare, birthing practices have not changed much over many generations; women rely almost exclusively on assistants who lack any formal training. “Hospitals” are little more than ordinary community buildings that are held in reserve for unsophisticated emergency medical care.
Even though the vast majority of births in the United States continue to occur in hospitals, other circumstances of deliveries have slowly begun to change. Two generations ago, women were mostly isolated in the delivery room; it is now common for supportive partners, and even multiple friends and family members, to witness a delivery. Active participation by part- ners and spouses has become routine. In addition, nurses and certified midwives who are trained in the care of pregnant women are gradually increasing their presence in the hospital delivery room. Uncomplicated vaginal births attended by certified midwives recently reached an all-time high in the United States, at 11%. And in technologically advanced Asian and Euro- pean countries, midwifery occurs at three to four times that rate (Declercq, 2012).
Section 4.1Variations in Birthing Practices
Research on the effectiveness of midwifery offers seemingly contradictory findings. A large Dutch study that compared a combined 529,688 planned home versus planned hospital births found no increased risks for midwifery; a follow-up study of nearly two million births even found some medical advantages, like a reduced chance of internal bleeding (de Jonge, Mesman et al., 2013; de Jonge, van der Goes et al., 2009). In contrast, a different analysis of 549,607 women found that home birth with a midwife tripled the risk of early infant death (Wax et al., 2010). Conclusions in these large-scale studies are therefore beset by contro- versy, mostly involving the matching of the comparison groups. That is, factors related to health or education may contribute to more variation than the location of the birth. Despite the controversies, midwifery appears to be an important bridge in providing skilled ser- vices in poorer countries, where a severe shortage of birthing professionals exists (Fauveau, 2011).
As a kind of compromise between home and hospital births, a newer model includes spe- cialized birthing centers, sometimes as an annex to a hospital. They appear as a blend of a hotel and a community health clinic. Well-trained staff are usually present, but immediate access to emergency medical treatment often is not. These kinds of alternatives forecast greater acceptance of doulas. Whereas midwives function primarily as medical professionals to assist during the birthing pro- cess, doulas provide supplementary educational, emo- tional, and physical support throughout the pregnancy as well as the postpartum period. In many ways, dou- las act like a “best friend” and coach for new mothers, though some (in lieu of a midwife or doctor) provide assistance during birth as well. Histori- cally, doulas were the norm until 20th-century medicine began to isolate births in hospitals (Dundek, 2006). However, the tide has begun to turn back toward less traditional medicine in the United States, partly because of the influx of immigrants and the resulting melt- ing pot of cultures.
One such example comes from Minnesota. Because of the civil unrest in Somalia begin- ning in 1991, a large number of refugees settled in the Twin Cities area. Pregnant Somali women are traditionally attended to by doulas, so in 2002 a pilot program was implemented in order to meet their differ- ent cultural needs. Outcomes among those who were attended by a doula were com- pared to those who were not. Among 123 women, the support provided by doulas during and after the birth process led to fewer medical interventions during deliv- ery and higher overall satisfaction with the birth experience (Dundek, 2006). The find- ings in Minnesota are consistent with other studies (e.g., Campbell, Lake, Falk, & Backstrand, 2006; Kozhimannil, Hardeman, Attanasio, Blauer-Peterson, & O’Brien, 2013; Simkin & O’Hara, 2002). The emotional and financial benefits of including doulas as part of the professional health care team may become an attractive option in the United States.
Critical Thinking Investigate and then compare and contrast midwives and doulas. What are the advantages for each?
Ruth Jenkinson/MIDIRS/Science Source ሁ Outside the United States, midwives and
doulas are very common. Here a midwife checks on a woman in labor who opted for a home birth.
Section 4.1Variations in Birthing Practices
Birthing Methods and Delivery Options Throughout the world, women use vastly different nonpharmacological pain management procedures, even when there is similar knowledge of techniques (Robertson & Johansson, 2010). Women squat and often sit upright when giving birth. These positions allow women to visually confirm the infant’s emergence and adjust the birthing process accordingly. In addi- tion, women who are supported by a partner in an upright position report less pain than those who give birth lying on their backs (Eberhard, Stein, & Geissbuehler, 2005).
In the Lamaze method, which receives the most attention in the United States, women attend classes with partners, usually the father, who serves as coach. The idea of Lamaze is to make delivery as natural and as comfortable as possible, regardless of circumstances. The coach learns to guide breathing and muscle relaxation exercises during labor and delivery. The techniques and support initiated by the Lamaze method are associated with less medication, easier labor, and a more positive birth experience (Lothian, 2011).
Other, less commonly publicized birthing methods include water births (sometimes referred to as the LeBoyer method) and self-hypnosis. These methods are intended to reduce pain and to be less traumatic for the infant. However, some research indicates that infants born in water are actually less healthy immediately after birth, though there is no difference at 5 minutes postpartum (Menakaya, Albayati, Vella, Fenwick, & Angstetra, 2013). Recently, more women have begun to use hypnosis during labor. This technique is sometimes called the Mon- gan method but is formally referred to as HypnoBirthing (Mongan, 1989). The goal in this method is to relax during the birth process instead of engaging in the huffing and puffing, grunting, and pushing associated with other delivery methods.
F O C U S O N B E H A V I O R : P a r e n t E d u c a t i o n Psychologists and other health care professionals are frequently asked about the “best” baby and childcare books. It is a gargantuan task to comb through the thousands of avail- able books and online materials. My advice for expectant parents is to find one book— two at the most—that they really like and stick with it. Websites and blogs are easier to browse, but parents may get caught up in looking for too much information. Parents-to-be are stressed enough, and free time will be at even more of a premium after birth. They do not need to overwhelm themselves with excessive opinions and information from multiple sources. If you are expecting a child, ask your friends what they read, visit some online sources including those that have book reviews, and then decide for yourself what materials you will depend on, knowing that there is usually more than one approach to every issue.
S E C T I O N R E V I E W Construct a short lecture about various birthing practices.
Section 4.2Stages of Childbirth
4.2 Stages of Childbirth There are three distinct stages of labor and childbirth: dilation and effacement of the cervix, delivery of the baby, and delivery of the placenta. The first physical sign that birth is approach- ing often occurs when the baby “drops” lower into the uterus (sometimes called lightening) up to 3 weeks before labor begins. With the guidance of hormones, labor nears and the mucus plug that sealed the cervix may be discharged (the bloody show), especially if the cervix has begun to dilate. When the amniotic sac ruptures (the “water breaks”), the fetus is left without the protection provided by the amniotic fluid. At that point, the birthing process is imminent. If labor does not begin at this time, it is usually medically induced with synthetic hormones.
Stage 1: Dilation and Effacement of the Cervix The first stage of childbirth occurs when contractions begin. The muscles of the uterus lit- erally begin to contract in order to push the baby out. Contractions start out 10–20 minutes apart and last 10–20 seconds; the contractions get closer and closer together, last longer, and usually become more painful. Just before birth, contractions might be 2 minutes apart and last up to a minute. Uterine contractions cause dilation (enlargement of the cervical opening) and effacement (a thinning of the cervix) so that the baby can pass through the birth canal. On average, stage 1 of labor lasts about 8 hours for a first birth and about 4 hours for subse- quent births (Zhang, Troendle, & Yancey, 2002). When contractions are at their peak and the cervix opens completely to 10 centimeters (cm), or about 4 inches, transition has occurred, signaling the next stage of labor (Figure 4.1).
Figure 4.1: Effacement and dilation of the cervix during stage 1 of labor
ሁ When the cervix is fully dilated to 10 cm and effaced (thinned), the baby is ready to pass through the birth canal.
Alila Medical Media/Shutterstock.com
Section 4.2Stages of Childbirth
Stage 2: Delivery of the Baby After the cervix is fully dilated, the baby’s head appears (crowning) at the vaginal opening. This period may last up to an hour, but like stage 1 it is shorter with subsequent births. Pow- erful contractions push the baby through the birth canal.
Stage 3: Placenta The last stage of labor includes the final contractions that dislodge the placenta from the uterus. This stage is the shortest of the three, lasting between 5 and 30 minutes. In a full- term pregnancy, the placenta may be 1.5 inches (3.8 cm) thick and weigh up to 2 pounds (907 grams).
Cesarean Section When the fetus is in a position that makes a vaginal delivery difficult or impossible, surgery is necessary to remove the baby. For instance, when the baby is in a breech position, its buttocks or feet are positioned first. In this case, a vaginal delivery can prevent the baby from breathing normally and may therefore be dangerous. Sometimes the umbilical cord is wrapped around the baby’s neck or is in a position where contractions cut off blood flow to the cord. When
oxygen or blood flow is restricted, the baby can experi- ence anoxia, or oxygen deprivation. Anoxia can result in brain damage or death, but immediate surgical interven- tion often prevents permanent damage.
When vaginal deliveries put either the mother or the baby in danger, the baby is delivered by an incision through the abdomen and uterus, called a cesarean sec- tion (C-section). Though these surgeries have become somewhat routine in the United States and many other countries, cesarean deliveries are nevertheless major surgical procedures that require many weeks from which to recover fully. Mothers remain hospitalized for 4 or more days and cannot easily care for their newborns without substantial assistance.
From a medical standpoint, there are potentially fewer birth complications from cesarean section as opposed to vaginal delivery. That is, it is more difficult to legally attribute birth defects to a cesarean delivery than to a vaginal delivery. Consequently, the increased threat of lawsuits following vaginal deliveries has contributed to the current record-high rate of full-term cesarean deliv- eries in the United States, of 30.1% (Osterman & Martin, 2013). By contrast, the rate of early-term C-sections has been declining among all racial and ethnic groups. It is
suggested that this trend is due mostly to a decrease in labor induction, since women who are induced are nearly twice as likely to have C-sections, compared with women who begin spontaneous labor (Zhang et al., 2010). Moreover, delivery method may be influenced more by a doctor’s specialty (e.g., surgery) rather than clear medical necessity (Aliaga et al., 2013; Reddy et al., 2012).
asiseeit/Vetta/Getty Images ሁ Although cesarean sections are
quite common, there is still extensive surgical involvement.
Section 4.3Newborn Assessment
S E C T I O N R E V I E W Explain the stages of childbirth. Make sure to describe distinct processes.
4.3 Newborn Assessment Regardless of delivery method, a quick evaluation of the newborn’s health is typically assessed using the Apgar scale, devised by Dr. Virginia Apgar in 1953. According to the Apgar scoring system, infants are assessed on five objective signs: appearance, pulse, gri- mace, activity, and respiration (APGAR), as outlined in Table 4.1 (Apgar, 1953). Measuring the same five dimensions, modern health care professionals also refer to the mnemonic “How Ready Is This Child” (heart rate, respiration, irritability, tone, color). A score of 7 to 10 indicates a healthy condition, 4–6 indicates some medical intervention is necessary, and a score of 3 or lower indicates the possibility of long-term neurological consequences if imme- diate medical interventions are postponed. Infants are assessed at 1 minute and at 5 minutes after birth. A score of 10 is relatively rare at 1 minute, so new parents should not be alarmed with a less-than-perfect score.
Table 4.1: Apgar scale ሁ The key terms of the Apgar scale can also be recalled by the mnemonic “How Ready Is This Child”
(heart rate, respiration, irritability, tone, color)
Observation Score
0 1 2
Heart rate Absent < 100 beats per minute > 100 beats per minute
Respiratory effort No breathing Slow, shallow breathing; weak cry
Regular breathing; good cry
(Reflex) irritability None Some response Vigorous response
(Muscle) tone Limp Some flexion of arms and legs Active motion of arms and legs
Color Blue or pale Pink body, blue arms or legs Completely pink
Source: Adapted from Apgar, 1953.
The Apgar scale is also frequently used in research to compare variables like obstetric practices, the stress- ors of anesthesia, or different delivery outcomes. For instance, in Apgar’s original research, when mothers were under general anesthesia (rarely administered now), their infants had an average Apgar score of 5.0; when mothers were given a spinal anesthetic, the Apgar average was 8.0. Further, cesarean deliveries in general are associated with lower Apgar scores, even when vaginal deliveries become complicated by instrument delivery or the fetus’s turning to a breech position (Atanasova, Slavkova, Yonov, & Valkova, 2012).
Critical Thinking Other than the procedure itself, offer an alterna- tive explanation for why C-sections are associ- ated with lower Apgar scores.
Section 4.4Preterm, Low-Birth-Weight, and Small-for-Date Infants
4.4 Preterm, Low-Birth-Weight, and Small-for-Date Infants Full-term infants in the United States and other developed countries weigh, on average, more than 7 pounds (3,200 grams) and are about 20 inches (51 cm) long. Infants who are born underweight or more than 3 weeks before their due date have greater risks for short- and long-term complications. In order to compare research outcomes that lead to consistent, opti- mal treatment, we differentiate among infants born to typical circumstances and those who are born with less-than-ideal size.
Low-Birth-Weight and Small- for-Date Infants Babies that weigh less than about 5.5 pounds (2,500 grams) are classified as low-birth- weight infants. Most, but not all low-birth- weight infants are born before 37 weeks gestation and are therefore also classified as preterm infants (preemies). However, not all low-birth-weight infants are premature. Babies are classified as small-for-date (or small for gestational age) when they weigh less than 90% of infants of the same gesta- tional age (i.e., they are at the 10th percen- tile for weight). In a comprehensive study of 2,764 infants in Israel, Regev et al. (2003) found that the chance of death for small-for-
date infants was 4.5 times greater than for average-size infants, their risk of chronic lung diseases of infancy increased by a factor of 3.5, and incidence of permanent damage to the visual system doubled.
Very-Low-Birth-Weight and Extremely-Low-Birth-Weight Infants Newborns who weigh less than 3.31 pounds (1,500 grams) are defined as very-low-birth- weight infants. These infants are at highest risk for birth defects and lifelong disabilities. Most very-low-birth-weight infants are preterm, but others simply do not grow sufficiently in the uterus. They are more susceptible to digestive tract and blood infections, are at higher risk for developmental and learning disabilities, and are especially vulnerable to heart and respiratory disorders (Boghossian et al., 2010).
Those born with a weight of between 14.1 ounces and 2.2 pounds (400–1,000 grams) are susceptible to additional complications. Compared to others, these extremely-low-birth- weight infants have a markedly higher risk of dying or developing a disability (Wadhawan et al., 2011).
Despite a recent overall decline, preterm deliveries that result in low birth weights vary greatly among racial and ethnic groups (Figure 4.2). For instance, preterm births occur 60% more often among black infants than white infants, a disparity that has remained somewhat consistent for more than a decade. Differences in education and access to health care (especially prenatal care) among blacks, Hispanics, and whites account for a significant proportion of the variation. Cultural attitudes and traditions toward pregnancy and childbirth may play a role as well.
©Annie Griffiths Belt/Corbis ሁ Low-birth-weight infants usually spend
significant time in infant intensive care, often receiving respiratory assistance.
Section 4.4Preterm, Low-Birth-Weight, and Small-for-Date Infants
Figure 4.2: Delivery outcomes among various racial and ethnic groups
ሁ In the United States, preterm deliveries rose more than one-third over a recent 25-year period. However, new data show four straight years of decline, to 12% of all births. The percentage of preterm deliveries has declined among Hispanics, blacks, and whites and in all age groups (Martin et al., 2013). Despite these gains, there is a high probability that socioeconomic status contributes significantly to group differences.
f04.02_PSY104.ai
1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012 2013
1990 0
8
12
16
20
P e rc e n t
Non-Hispanic black
Non-Hispanic white
Total
Hispanic
Source: Hamilton, B. E., Martin, J. A., Osterman, M. J. K., & Curtin, S. C. (2014). Births: Preliminary data for 2013. National vital statistics reports, 63, No 2. Hyattsville, MD: National Center for Health Statistics.
Causes Notably, although babies born before 32 weeks gestation account for only 2% of live births, they account for over 68% of all infant mortality. Though up to half of premature births and low birth weights are unexplained, the increase in maternal health problems related to obe- sity and diabetes account for a significant proportion of these births (Crane, White, Murphy, Burrage, & Hutchens, 2009; Denison et al., 2013; Harder, Dudenhausen, & Plagemann, 2012). In addition, more frequent use of assisted reproductive technology has led to large increases in multiple births, which in turn produces more preterm births. The risk of low birth weight among triplets and higher-order multiples is more than 30 times the rate of single births (Wad- hawan et al., 2011).
As Figure 4.3 shows, there are distinct distributions for length of gestation among single- tons, twins, and triplets (Alexander, Kogan, Martin, & Papiernik, 1998). On average, twins are delivered 3 weeks earlier than singletons and weigh 2.1 pounds (968 grams) less; triplets are delivered more than 6 weeks earlier and weigh 3.6 pounds (1,622 grams) less, a deficit of more than half of normal birth weight. More than 50% of twins and 90% of triplets are both preterm and low birth weight, compared to about 9% of singletons who are preterm and 6% who are low birth weight.
Section 4.4Preterm, Low-Birth-Weight, and Small-for-Date Infants
Figure 4.3: Birth weight characteristics of singletons, twins, and triplets, by gestational age
ሁ There are distinct distributions for length of gestation among singletons, twins, and triplets. On average, twins are delivered 3 weeks earlier than singletons and weigh 2.1 pounds (968 grams) less; triplets are delivered more than 6 weeks earlier and weigh 3.6 pounds (1,622 grams) less. More than 50% of twins and 90% of triplets are both preterm and low birth weight, compared to about 9% of singletons who are preterm and 6% who are low birth weight.
P e rc
e n
t d
is tr
ib u
ti o
n
0
5
10
15
20
25
Gestational age in weeks 22 23 24 25 27 28 29 30 3126 32 33 34 36 37 38 39 4035 41 42
Singletons, 1995
Twins, 1991–1995
Triplets, 1991–1995
Source: From G. Alexander, et al., “What Are the Fetal Growth Patterns of Singletons, Twins, and Triplets in the United States?” Clinical Obstetrics and Gynecology, 41(1). Copyright © 1998, Wolters Kluwer Health.
These multiple births seem to add another dimension of risk. A recent study analyzed the birth and growth records of over 11,000 extremely-low-birth-weight infants, those born with a weight of between 14.1 ounces and 2.2 pounds (400–1,000 grams). Among infants of com- parable size and gestational age, triplets are markedly more at risk of dying or developing a disability compared to single births and twins. Given the more than 400% increase in triplets and higher multiples beginning in the early 1980s, this evidence supports the need to find ways to increase gestational age and birth weight, especially among the increasing numbers of multiple births (Wadhawan et al., 2011).
When low-birth-weight and preterm children enter school, they remain at much higher risk for a number of developmental problems. Overall, there is a higher incidence of behavioral problems and general cognitive deficits (Olivieri et al. 2012). These children have a higher than expected rate of placement into special education classes and exhibit a wide range of motor impairments and math and language learning disabilities (Wocadlo & Rieger, 2006, 2008). In addition, the severity and complexity of the learning disabilities is associated with the degree of motor impairment. Not unexpectedly, the severity of these deficits is also posi- tively correlated with the amount of respiratory support a child received as a neonate (the period between birth and 1 month of age)—more respiratory support during the neonatal period is associated with the likelihood of impairments.
Section 4.5Early Infant Care
Intervention Strategies The news on infants who are of low birth weight is not all bad. In particular, new technolo- gies have significantly reduced the death rate among low-birth-weight infants, though trends have slowed more recently (Kalkan et al., 2007; C. Lau, Ambalavanan, Chakraborty, Wingate, & Carlo, 2013). Early intervention programs that include emotional support of the infants (holding and stroking), massage therapy, parental support, and educational support have been found to be successful for the majority of low-birth-weight babies who were not small- for-date (Field, Hernandez-Reif, & Freedman, 2004; Hill, Brooks-Gunn, & Waldfogel, 2003; Watson, 2013). Evidence shows that skin-to-skin contact (“kangaroo care”) should be an inte- gral part of treatment as well. It has been a valuable strategy in reducing crying, regulating heat and body rhythms, improving cognitive and motor growth, and promoting overall sur- vival and development (Feldman & Eidelman, 2003; Kostandy et al., 2008; Salimi, Khodayar- ian, Bokaie, Antikchi, & Javadi, 2014; Shrivastava, Shrivastava, & Ramasamy, 2013).
We now know that nearly every baby benefits from physical stimulation, even the most frag- ile. But due to the especially delicate nature of small infants, they are often housed in isolated, protective chambers. To compensate for the largely sterile environment, Field and her col- leagues have been instrumental in developing specific interventions strategies (see, e.g., Field, Diego, & Hernandez-Reif, 2010). Techniques involve specific kinds of limb flexing, touching, and massage. As a result, low-birth-weight babies become generally more alert, show greater motor development, and go home earlier. Many hospitals now include vol- unteers whose sole job is to hold and massage these children. More recently, music therapy has joined the list of possible intervention strategies. Recent results have sug- gested that, rather than being a source of overstimulation, intentional use of lullabies and other live sounds can have a positive effect on a premature infant’s heart rate, sucking behavior, sleep patterns, and calorie intake (Loewy, Stewart, Dassler, Telsey, & Homel, 2013).
S E C T I O N R E V I E W Differentiate among preterm, low-birth-weight, and small-for-date infants. Describe conse- quences and treatments for preterm infants.
4.5 Early Infant Care Like preterm infants, full-term infants also need a tremendous amount of care and attention. Initial thoughts about infant care usually revolve around diapering, feeding, and other physi- cal aspects of behavior. But early care encompasses a whole range of cognitive and psychoso- cial aspects, too. This section explores factors related to the health and well-being of infants that affect all developmental domains.
Section 4.5Early Infant Care
Bonding In contrast to the beliefs of many child developmentalists and psychologists of the early to mid-1900s, ethologists like Konrad Lorenz argued in the latter half of the century that the moments after birth were essential to proper psychosocial development. According to Lorenz and oth- ers, there is a critical period of only a few hours right after birth that initiates bonding, the close physical and emotional contact between parent and child. Remember, though, that Lorenz studied geese and other bird species, so his views were often dismissed. Therefore, even as late as the 1960s, women were routinely drugged during childbirth and were not conscious enough to connect immediately with their children. Infants were usually separated from their mothers after delivery (and fathers were generally excluded from the process altogether!).
Many childcare professionals argue that newborn infants need to feel emotionally close in order for optimal devel- opment to take place. However, researchers have found that it is not critical for that period to begin immediately after birth. For example, parents of adoptive children and neonates who are separated from their parents for medi- cal reasons show patterns of psychosocial development similar to those who are immediately placed with their parents (Myers, 1984). For adoptive children and their parents, it is probably reassuring to know that research has not supported the ethological view. Although infants benefit tremendously from touch and emotional close- ness, immediate postnatal moments do not appear to have a lifelong impact on emotional development. Nev- ertheless, bonding is thought of as an important time for
new parents. And like the therapy strategies mentioned previously, early contact can reduce stress for parents as well as infants (e.g., Loewy et al., 2013).
Postpartum Depression Stress is only one byproduct of having a new child. The excitement of birth sometimes gives way to a letdown as hormones and emotions adjust to normal levels. Both mothers and fathers may suffer from “baby blues” as they settle in to sleepless nights and stressful days. Mothers especially may suddenly be overcome with emotion and experience temporary mood swings. For the vast majority of mothers, these feelings go away a few weeks after delivering. How- ever, about 10% of mothers suffer from a more serious condition called postpartum depres- sion. It is characterized by crying fits, changes in appetite, changes in sleep (a lot more or a lot less), a lack of joy, and a feeling of hopelessness.
Consequently, infant care and nutrition are affected by the mother’s mental state (Hurley, Black, Papas, & Caulfield, 2008). And infants respond in kind. Evidence suggests they expe- rience more emotional problems, including sadness and anger, and delays in cognitive
Graham Monro/gm photographics/ Photolibrary/Getty Images
ሁ There is some controversy about whether bonding is critical to development. For the vast majority of infants and parents, an emotional connection will eventually occur even if it does not in the first moments after delivery.
Critical Thinking Can bonding be a one-way relationship, or does it need to be reciprocal?
Section 4.6Infant Nutrition and Health
development (American College of Obstetricians and Gynecologists, 2006; Patel et al., 2012; Tran et al., 2013). Early intervention for postpartum depression is therefore essential. Medi- cal treatment (antidepressant medication) is often prescribed in conjunction with psycho- logical counseling. Although there are not enough studies to make definitive conclusions, preliminary analyses point to the advantage of drug therapy over the moderate psychologi- cal benefits of counseling (Cuijpers, Brännmark, & Annemieke, 2008; Fitelson, Kim, Baker, & Leight, 2011; O’Mahena et al., 2012). However, the addition of counseling is necessary so that families can learn coping strategies, such as fathers and other adults providing emotional warmth to the baby. In most cases, short-term treatment is successful.
S E C T I O N R E V I E W Describe how the initial parent-child relationship and each domain of development may be affected by postpartum depression.
4.6 Infant Nutrition and Health As nature probably supplies the backdrop for initial infant experiences, the environment also provides an immediate force in early infant care. For instance, a common discussion among new parents in the United States concerns sleeping habits and when infants should be expected to sleep through the night. Nutrition is another area where considerable overlap exists between nature’s early demands and the potential variation that the environment may offer. In considering the effect of early experiences on health, this section examines issues related to initial sleep habits, feeding infants formula versus breast milk, and the conse- quences of good versus poor nutrition.
Cosleeping Most parents in the United States almost immediately begin preparing their children to sleep through the night. They try to ensure that their infants are well fed right before beginning their extensive, often stressful nighttime routine. By contrast, many cultures manage chil- dren’s sleeping arrangements by cosleeping, that is, sharing a bed. Cosleeping is described as the norm throughout the world, including both less developed countries and those that are technologically advanced, like South Korea (McKenna & McDade, 2005; Mindell, Sadeh, Kohyama, & How, 2010). Because of the relative lack of nighttime stress, rates of full-time bed sharing in the United States have risen from 6.5% to 13.5%, but a substantial number of parents cosleep at least part time (Colson et al., 2013; Krouse et al., 2012).
The biggest killer of postneonatal infants is sudden infant death syndrome (SIDS). It is characterized by the sudden “crib death” of seemingly healthy infants during sleep. For centuries, its cause has remained a
Critical Thinking The best argument for cosleeping is that it takes the stress out of bedtime routines. Cosleeping advocates argue that children will eventually move to their own rooms voluntarily, but many children do not express this need until adoles- cence. Therefore, in some ways it may remain less stressful to allow children to sleep with their parents and in other ways it may be more stressful. Use this information to decide when, if at all, you think cosleeping should end.
Section 4.6Infant Nutrition and Health
mystery. It is likely related to the infant’s inability to wake up when there is a buildup of carbon dioxide in the blood. This condition may result from a combination of genetic and environmental factors, including exposure to secondhand smoke and a baby’s sleep position (Athanasakis, Karavasiliadou, & Styliadis, 2011).
The most important factor in the reduction of SIDS risk is attributed to the recommendation that infants be put “back to sleep.” That is, the American Academy of Pediatrics (AAP) recom- mends that infants be placed on their backs when put down to bed rather than on their stom- achs or sides (AAP, 2011). Since the original recommendation in 1992, the incidence of SIDS has declined dramatically, as shown in Figure 4.4. (Note, however, that the incidence of SIDS had been dropping prior to the original AAP recommendation.)
Figure 4.4: SIDS rate and sleep position, 1989–2006 ሁ From 1989 to 2006, as back sleeping increased, SIDS rates decreased.
M o
rt a li ty
r a te
p e r
1 ,0
0 0 l iv
e b
ir th
s
0
0.5
1
1.5
19 88
19 89
19 90
19 91
19 92
19 93
19 94
19 95
Year
19 96
19 97
19 98
19 99
20 00
20 01
20 02
20 03
20 04
20 05
20 06
20 07
P e rc
e n
t b
a c k s
le e p
in g
0
19 92
19 93
19 91
19 94
19 95
19 96
19 97
19 98
19 99
20 00
20 01
20 02
20 03
20 04
20 05
20 06
20 07
Year
20
40
60
80
13 17
26.9
38.6
35.3
53.1
55.7
64.4
66.6
71.6
71.1
72.8
70.1
72.2 75.7
76.1
Source: Adapted from Colson et al. (2009) and Centers for Disease Control and Prevention (2014e).
Section 4.6Infant Nutrition and Health
Cosleeping and SIDS Because studies have found the incidence of SIDS to be higher when parents cosleep, the fed- eral Consumer Product Safety Commission says, “The only safe place for babies to sleep is a crib [with] a tight-fitting mattress” (p. 134). The AAP Task Force on Sudden Infant Death Syn- drome (2011) agrees. They have twice reaffirmed the need for back sleeping and avoiding soft bedding. On the other hand, the well-known authors of Sleeping with Your Baby: A Parent’s Guide to Co-sleeping suggest that in order to reduce the incidence of SIDS, “babies should never sleep alone” (McKenna & McDade, 2005, p. 134). They attribute the reduced incidence of SIDS in part to the tandem effect of increased breast- feeding and mother-infant cosleeping.
New, multinational research across Europe epitomizes the bed-sharing controversy. Research- ers suggested that 90% of SIDS deaths that involved a shared bed would not have occurred if children were in their own beds, stating that “professionals and the literature should take a more definite stand against bed sharing” (Carpenter et al., 2013). However, part of the reason for professionals to take a more definitive stand is because parents who smoke, drink, or take drugs are not heeding professional advice. Therefore, if everyone adhered to a unified mes- sage to avoid cosleeping, it would prevent SIDS among those infants who are at highest risk. The recommendations of the AAP Task Force, the U.K. Department of Health, and the recent UNICEF-UK Baby Friendly Initiative statement are all available to download at no cost.
Breast versus Formula Feeding Though much less impassioned, another bit of a controversy remains with regard to feed- ing by breast or formula. The adage “breast is best” has received renewed emphasis as more mothers in the United States have committed to breastfeeding. At the same time, millions have grown up on formula without any apparent disadvantages, which has also allowed fathers to play a larger role. Beginning around the time of the baby boom in the late 1940s, it was
Critical Thinking What advice would you give parents who are concerned about SIDS?
Jupiter images/photos.com/Thinkstock Photodisc/Thinkstock ሁ Though “breast is best,” children who are formula-fed will still develop
normally.
Section 4.6Infant Nutrition and Health
thought that formula feeding was in many ways superior to breastfeeding. The leading argu- ment in favor of formula was that parents could control the amount and timing of nutrition. Parents could be assured that their children were well fed by giving them premeasured amounts of formula. The trend toward replacing breast milk with formula continued in the United States until the early 1970s, when it began to reverse.
Today there is consensus among doctors and developmentalists that breastfeeding should be pursued whenever possible. Breastfeeding is correlated with significant reductions in the prevalence of asthma; some forms of cancer; and respiratory, diarrheal, and ear infections. There is reduced incidence of obesity throughout the lifespan and a lowered risk of diabetes (AAP, 2012; McNiel et al., 2010). And, after several key forums and research colloquia, the SIDS and Kids National Scientific Advisory Group of Australia concluded that evidence had reached a “critical threshold” to support breastfeeding as a specific measure for SIDS risk-reduction (Young, Watson, Ellis, & Raven, 2012). Research also suggests breastfeeding can lead to cog- nitive advances, perhaps due to the concentration of compounds found specifically in breast milk (AAP, 2012; Ryan & Nelson, 2008; Tanaka, Kon, Ohkawa, Yoshikawa, & Shimizu, 2009).
In accordance with these findings, the AAP states that the exclusive consumption of breast milk during the first six months or longer should be the “normative standard” and not sim- ply a lifestyle choice (AAP, 2012). The World Health Organization states that optimal feeding entails “exclusive breastfeeding” without any additional nutrition, including water (World Health Organization, 2013). In the United States though, exclusive breastfeeding in the first 3 months is the norm for only about 38% of infants (see Figure 4.5). Although the number of mothers who breastfeed has risen dramatically since the 1970s, gains have slowed consider- ably since the early 1990s (National Immunization Survey, 2014; Ryan, 1997).
Figure 4.5: Percentage of U.S. infants who are ever breastfed and those who are exclusively breastfed through 6 months
ሁ The number of mothers who breastfeed their infants has risen dramatically since the 1970s. However, the number of mothers who follow APA recommendations and breastfeed exclusively for at least 6 months remains at 16%, well below the target rate of 50%.
Early postpartum At 6 months
At 12 months
Exclusively through 3 months
Exclusively through 6 months
0
10
20
30
40
50
60
70
80
90
100
19 99
20 00
20 02
20 03
20 01
Year of birth 20
04 20
05 20
06 20
07 20
10
P e rc
e n
ta g
e
0
10
20
30
40
50
60
70
80
90
100
20 03
Year of birth 20
04 20
05 20
06 20
07 20
10
P e rc
e n
ta g
e
Source: National Immunization Survey (2014).
Section 4.6Infant Nutrition and Health
One major confounding variable in this research is how much of the breastfeeding advan- tage is due to human milk consumption and how much to the type of parent who chooses to breastfeed. Among women who breastfeed, there are significant differences in SES, the home environment, and parental intelligence. It follows that SES has an effect on how parents treat potential illnesses, including their identification and treatment, and how well their chil- dren perform cognitively. As Figure 4.6 shows, breastfeeding varies as a function of income level, education, and age, which are associated with developmental outcomes independent of breast versus formula.
Figure 4.6: Percentage of infants who are breastfed, by maternal age, race/ethnicity, and income level
ሁ Breastfeeding varies with maternal age, race/ethnicity, and income.
0
20
40
60
80
10
30
50
70
P e rc
e n
ta g
e P
e rc
e n
ta g
e
Total Non-Hispanic white
Non-Hispanic black
Mexican American
Total Non-Hispanic white
Non-Hispanic black
Mexican American
0
20
40
60
80
10
30
50
70
Lower income
Higher Income
Under 20 years
30 years and older
20–29 years
Source: Breastfeeding among U.S. Children Born 1999–2007, CDC National Immunization Survey.
Section 4.6Infant Nutrition and Health
In developing countries, the issue of breast milk versus formula takes on a different tone, as described in Focus on Behavior: Encouraging Healthy Infants.
F O C U S O N B E H A V I O R : E n c o u r a g i n g H e a l t h y I n f a n t s Due largely to the lobbying efforts of the formula makers, many parents in developing countries have erroneously believed that formula is superior to human milk. In addition, due to poor economic conditions, families will often dilute formula, which means it pro- vides less than optimal nutrition. This problem leads to an estimated 1.5 million deaths annually among formula-fed infants in developing countries (UNICEF, 2013). In response, the World Health Organization (WHO) adopted a code in 1981 calling for a ban on the pro- motion of formula, especially in the form of free samples given to new mothers in hospitals.
In the 1990s, WHO and UNICEF collaborated on the Baby-Friendly Hospital Initiative (BFHI) to encourage hospitals and birthing centers to provide a plan for mothers to gain the confidence and skills needed to breastfeed exclusively. Hospitals and birthing centers receive a “Baby-Friendly” designation by following the BFHI guidelines.
According to UNICEF (2009), after implementing BFHI in China, exclusive breastfeeding rates increased in urban areas from 10% to 47% over 2 years. In Zambia, rates doubled over 5 years; and in Nicaragua breastfeeding rates increased from 47% to nearly 100%, including 39% at the 20-month mark. Unfortunately, however, mothers do not always fol- low through. Though an alarming 10% of Nicaraguan babies are malnourished, only 31% of them were exclusively breastfed through 6 months. Nevertheless, in the United States and throughout the world, these data suggest a strong relationship between BFHI and an increase in breastfeeding, especially in high-risk populations (Parker et al., 2013).
Finally, there are many circumstances when breastfeeding either cannot take place or is not indicated. Mothers should not breastfeed when they carry infectious diseases like AIDS or tuberculosis or when they are taking medication that can be ingested through breast milk. In addition, adoptive parents and those who have physical difficulties or insufficient breast milk also do not breastfeed. On the other hand, many fathers and others cherish the opportunity to share these new joys. Fathers of bottle-fed babies have the advantage of increased participa- tion in feeding, which also allows new parents to decrease the stress associated with having a new infant.
Psychosocial Factors: Nonorganic Failure to Thrive Sometimes children who receive sufficient nutrition nevertheless cease to grow; they behave as if they are starving. Their symptoms mimic the listlessness and underdevelopment of those suffering from marasmus, a severe form of malnutrition. These children do not present any biological cause for growth failure but begin to starve because they have been denied appropriate affection, emotional support, and stimulation. These cases usually occur before 18 months and are known as nonorganic failure to thrive.
In a series of famous experiments with monkeys, Harry Harlow demonstrated dramatically what would happen when infant monkeys were socially isolated or were denied affection. In
Section 4.7Infant States of Arousal and Sensory Capacities
one experiment, Harlow separated baby rhesus monkeys from their mothers soon after birth and provided nutrition only from a bottle. He soon noticed that the infant monkeys formed an attachment to the soft material that lined their cages. When the material was removed, the monkeys threw violent temper tantrums.
In a series of follow-up experiments, he first raised monkeys in a cage with a bare floor. Those monkeys struggled even to survive. Next, Harlow supplied wire-mesh cones and the babies did better. Finally, he covered the wire cones with soft terry cloth to form “surrogate” moth- ers and discovered that “husky, healthy, happy babies” emerged. Rather than mothers simply providing sustenance through the breast, as Freud may have theorized, Harlow demonstrated that affection is necessary for infants to survive and he provided insight into the process of nonorganic failure to thrive. “Above and beyond the bubbling fountain of breast or bottle, contact comfort might be a very important variable in the development of the infant’s affec- tion for the mother” (Harlow, 1958, emphasis added). That is, the physical contact was an important factor in an infant’s sense of contentment. Although early failure to thrive puts chil- dren at higher risk for slower physical growth and lower cognitive functioning, intervention programs that include home visits and behavioral therapy for parents have been found to be successful (Black, Dubowitz, Krishnakumar, & Starr, 2007).
S E C T I O N R E V I E W Analyze the effects of early experiences on health and development, including sleeping and eating practices.
4.7 Infant States of Arousal and Sensory Capacities Whereas decisions related to nutrition have lifelong consequences, typical characteristics of initial infant behavior are less variable. Young children are hardly the tabula rasa described by John Locke. We are programmed even from conception for certain behaviors and charac- teristics, such as walking, babbling, and expressing emotions. At least some senses operate at a high level beginning right at birth. This section explores the behaviors that are universal to infancy as well as the emergent sensory systems.
Infant States of Arousal Neonates cycle through different states of arousal, just like adults. States range from active alertness to quiet, restful sleep (see Table 4.2). But infants also have states of quiet alertness and active sleep. Actively sleeping infants may make faces and appear distressed, but they regularly sequence through these actions. The nervous system becomes increasingly inte- grated with behavior as internal forces like hunger and sleep cause changes in activity levels. Infants use internal and external cues to organize behavior. For instance, they use internal hunger cues to modify external behaviors like crying or latching to a nipple. As brain growth becomes more complex, states of sleep and wakefulness change as well.
Section 4.7Infant States of Arousal and Sensory Capacities
Table 4.2: Infant states State Characteristics
Alert activity Infant shows movement, often with rhythmic activity. Eyes are open and bright, with a shining quality.
Quiet alert Eyes are open but not necessarily focused. Motor activity is varied.
Drowsiness Infant is relatively inactive. Breathing is regular but more rapid than during sleep. Eyes may open and close intermittently.
Active (irregular) sleep Eyes are closed, and breathing is uneven. Infant makes frequent faces, which may include smiles, frowns, grimaces, sucking, and sighs.
Regular (quiet) sleep Eyes are closed, and face appears relaxed. Breathing is slow and regular.
Crying Baby vocalizes in response to hunger or discomfort, and makes varied motor movements.
In general, parents guide their infants from one state to another. For example, a crying infant initiates a response from parents, who attempt to transition the child from crying to the quiet alert state. At other times, the infant’s normal cycling through states is disrupted. For instance, parents who want to delay sleep for one reason or another may attempt to keep their babies awake when they observe them becoming drowsy. These states occur at regular intervals and for regular amounts of time, again indicating a biological basis for their occurrence.
Reflexes Though completely dependent on others for care, children are born with many capabilities. They have a number of well-developed reflexes and organized sensory responses that are
From left to right: iStockphoto/Thinkstock; Ami Parikh/iStock/Thinkstock; ©Gavriel Jecan/Corbis ሁ Infants cycle through five states of arousal, including crying, alert activity, and regular sleep,
shown here.
Section 4.7Infant States of Arousal and Sensory Capacities
present at birth (and even before). A reflex is an involuntary response to the environment. For instance, the rooting, sucking, and swallowing reflexes are related to feeding and survival. When a newborn’s cheek is stroked, it will turn its head in the direction of the stimulus, open its mouth and search for a nipple. It wants to find a secure “root” to become stable and secure. When an object like a finger or a nipple is placed into the mouth of the infant, the reflexive response is to suck, with surprisingly sustained force. Infants are also born with a reflex that allows them to swallow the liquid they received from the nipple. It is clear that these reflexes are survival mechanisms. There are others, like the Babinski and Moro (startle) reflexes, that may be evolutionary leftovers and are less understood (see Table 4.3).
Table 4.3: Examples of newborn reflexes ሁ Most reflexes will eventually fade and become voluntary behaviors.
Reflex Stimulation Response Function Development
Rooting Stroke cheek near the mouth
Baby orients to source of stimulation and makes feeding movements
An adaptive func- tion to find the nipple and aid survival
Disappears at 3 weeks when baby’s head turns voluntarily
Sucking Place finger or nipple in mouth
Strong, rhythmic sucking
An adaptive func- tion to permit feeding
Disappears at 4 months and becomes voluntary
Swallowing Place liquid in mouth
Swallow To gain nutrition Disappears at 4 months and becomes voluntary
Eye blink Expose eyes to bright light or puff of air
Baby quickly blinks or closes eyes
Protects eyes from damaging stimulation
Permanent
Moro (startle reaction)
Expose infant to a sudden “drop- ping” motion or a loud sound
Arms and legs are extended outward, then are pulled back toward body
Perhaps a “left- over,” primitive response to help infant cling to its mother
Fades at 6 months
Grasping (palmar grasp)
Place finger or object in hand
Baby makes fist around object
Probably pre- pares infant for grasping
Weakens at 3 months; disap- pears by 1 year
Stepping Hold baby upright with some tilt and move forward
Walking-like motions with legs
Thought to prepare infant for voluntary walking movements
Fades at 2 months; disap- pears at 4 months
Babinski Stroke the sole of the foot from heel to toes
Big toe curves and others fan out
Unknown Fades at 9–12 months
Section 4.7Infant States of Arousal and Sensory Capacities
Infant Sensation and Perception Infants begin to learn and adapt to the environment right away. The rooting reflex is an exam- ple of a response that is learned quickly. After less than a month, an infant actively moves to search for the nipple instead of waiting to be stimulated. Visual, auditory (hearing), olfac- tory (smell), and other sensations are already well developed by this age, meaning that the nerves activated by light, sound waves, or odor molecules are responsive. In addition, the infant brain is able to interpret what those sensations mean. This interpretation or awareness of the sensations is called perception.
Since infants cannot verbally communicate, the most common method of testing what infants can perceive is through the process of habituation (see Figure 4.7). Like anybody else, infants stop paying attention when they get bored with particular stimuli. At first, they attend to a novel stimulus and then their response reduces gradually, or they habituate. For instance, the first time newborns are presented with a rattle, they will turn their heads curiously. As the rattle continues to make noise, they will begin to lose interest until further shakes no longer bring a response. They have become habituated to the sound and sight of that particular toy. If infants then pay attention to a different rattle that makes a new sound or looks different, we know that they can discriminate among different sounds, colors, or shapes of rattles. Since they habituated to the first rattle but pay attention to the second, we know that they have per- ceived a change. Therefore, psychologists and developmentalists use the process of habitua- tion to understand and explore an infant’s sensory and perceptual capabilities.
Figure 4.7: Habituation and dishabituation ሁ In phase 1, the experimenter waits until the infant becomes habituated to the pattern
(uninterested in the stimulus). In phase 2, the experimenter presents either the original stimulus or one that is novel. Infants who have habituated in phase 1 attend to the original stimulus for a shorter period of time compared to the novel one. Infants who did not participate in phase 1 will attend equally to both stimuli. Habituation allows us to know when infants can discriminate between two stimuli.
Phase 1
Pha se 2
Section 4.7Infant States of Arousal and Sensory Capacities
F O C U S O N B E H A V I O R : H a b i t u a t i o n If you have children, you know that the coolest toys, the ones children really like, are those that are at someone else’s house. So you go out and purchase one of those cool toys, only to find your child is bored with it. When you go back to the other house, your child again finds that there are cooler toys there. Buying one of those new toys will once again leave you dis- appointed. Understanding habituation can save you money and some frustration. Like any- one else, children are attracted to novel stimuli. Children become habituated to their own toys, whereas toys that someone else has are new and exciting. So how can you combat this natural process?
One way is to use different containers for toys and activities. When every toy is always available, children habituate to all of them. If, instead, containers of toys are rotated every few weeks, they remain fresh and novel whenever they appear (dishabituation). Many parents make the mistake of constantly buying toys to keep their children stimulated, when they may have enough already.
Touch We know that touch is important for infants. It stimulates growth and showcases the begin- ning of psychosocial development. Because many reflexes depend on a sense of touch, we know that this sense is well developed at birth. One demonstration of touch occurred when French researchers used the process of habituation to see if 45 full-term neonates could tell the difference between a prism and a cylinder (Streri, Lhote, & Dutilleul, 2000). The objects were first placed into the children’s palms; the grasping reflex caused the neonates to reflex- ively grab on to them. Approximately half the neonates were given prisms, and the others were given cylinders. The children would eventually drop the object, but the research team would place it back into the palm. This pattern was repeated through nine trials. By the ninth trial, the children held the object, on average, for less than half the time of the first trial. They had begun to habituate.
The second part of the experiment involved placing the other object in the palm after the ninth trial. That is, if the neonate was in the cylinder group, he or she was given a prism, and vice versa. On average, the children held on to the novel stimuli more than twice as long as on the ninth trial with the habituated object, demonstrating a somewhat sophisticated sense of touch. According to the authors, this study provided the first experimental evidence of the ability of neonates to discriminate by touch between two different objects.
Smell and Taste When newborns turn in the direction of one smell over another, it indicates that they can discriminate between the two odors. Although the sense of smell is not as well developed in humans as in other mammals, it appears that neonates can discriminate among odors quite well. If 2- to 4-day-old neonates are exposed to their own or another baby’s amniotic fluid, they prefer their own (Marlier, Schaal, & Soussignan, 1998). And there is convincing evidence that neonates prefer their mother’s smell to that of strangers, including many studies that show breastfed infants are attracted to both the smell of their own mother and the smell of her milk (e.g., Cernoch & Porter, 1985; Makin & Porter, 1989). A more recent study found that
Section 4.7Infant States of Arousal and Sensory Capacities
neonates who experienced pain were calmed when they smelled their own mother’s milk compared to another mother’s milk or formula (Nishitani et al., 2009).
Experiments on odors mimic the way that infants orient toward familiar taste. For instance, parents who feed their children soy-based formula (because of allergies to animal-based for- mulas) are often concerned when their children initially reject the formula. However, infants readily begin to associate the new formula with hunger relief and soon learn to prefer its taste to other formulas. And Zhang and Li (2007) showed that newborns as young as 90 minutes can discriminate among four primary tastes. Neonates were exposed to sweet, salty, sour, and bitter tastes and then graded on intensity of expression and mouth actions. Over 93% of infants showed no distinct mouth expression when introduced to a sugar solution, compared to only 27% for a salt solution, 3% for a sour solution, and 21% for a bitter solution. For each taste, infants showed a different range of expressions, as shown in Figure 4.8.
Figure 4.8: Infant discrimination of taste ሁ By administering different taste solutions to 90-minute-old babies, Zhang and Li (2007) showed
that infants can discriminate among a number of different tastes. Facial changes in response to taste stimuli could be categorized among nine different expressions: Row A represents no distinct mouth action, B is a pursing action, and C is a gaping action. Whereas over 93% of newborns showed no distinct mouth or facial action (A1) when exposed to a sweet solution, nearly 70% exhibited one of the B responses when given the sour solution. Studies like this one show that even newborns have well-developed taste sensitivity.
Source: Used with permission of Zhang & Li (2007).
Section 4.7Infant States of Arousal and Sensory Capacities
Hearing The structure of the ear is nearly complete in the 4-month-old fetus. Perhaps that is why audi- tory processing of newborns appears to be similar to that of adults. Recall from an earlier dis- cussion that fetuses remember voices, language, rhymes, and melodies. However, in general, sounds need to be louder and higher in pitch than is necessary for adults (Olsho & Gillenwa- ter, 1989; Werner & Gillenwater, 1990). The tendency of adults—and even older siblings—to use the higher pitched, sing-song intonation of infant-directed speech might be nature’s way of responding to infant needs.
Though newborns are able to perceive sounds well, they are not yet experts at localizing them. Because ears are on opposite sides of the head, any sound waves that do not originate from a source equidistant from each ear (called the “midline”) will reach the auditory receptors in the ears at different times. At birth, infants are good at localizing sounds that are far from the midline (i.e., clearly to the left or the right side of the head). New parents easily observe this skill when they enter a room and they notice their child’s head turn in their direction. However, the closer a sound originates from the midline, the more difficult it is for an infant to localize the sound.
Vision Even though sight is highly developed in humans, it is the least developed of the senses at birth. Despite some controversy, infant vision is thought to become similar to that of an adult at as early as 6 months (Cavallini et al., 2002). The overall structure of the eye is mostly com- plete when the fetus is 4 months old, but the retinas (where the visual receptors are located) are not fully developed. The retina is not yet dense with the visual receptors for color (the cones) at birth, though they are present, which implies that newborns perceive color. In addi- tion, color perception may be so well developed by 12 weeks that infants begin to show pref- erences for certain colors over others; by 30 weeks, they can discriminate between the slight variations of gold and yellow (Yang, Kanazawa, & Yamaguchi, 2013; Zemach & Teller, 2007).
Though newborn vision is not sharp, infants can perceive shapes and patterns. Robert Fantz (1961) famously demonstrated that even 2-week-old babies prefer to look at patterns rather than plain stimuli. Infants are initially interested in simple contrasts like a bull’s eye, and by their third month, they begin to prefer more complex patterns (Brennan, Ames, & Moore, 1966). When given a choice among a number of objects, infants will stare longest at a human face (see Figure 4.9). Evolutionary psychology suggests that a built-in preference for faces is a survival mechanism that allows infants to read the environment, increasing their chances for survival.
Figure 4.9: Infant visual perception ሁ Robert Fantz famously demonstrated that infants prefer to look at more complex patterns, with
human faces being most preferred.
most preferred least preferred
Summary and Resources
Depth Perception In another famous experiment, Eleanor Gibson and Richard Walk (1960) constructed a “visual cliff ” to investigate whether or not infants had depth perception, or the ability to perceive distance and see in three dimensions. They built an elevated glass table, with one side consist-
ing of a checkerboard pattern and the other a sheet of clear glass that gave the illusion of a cliff. Infants aged 6–12 months were placed on the edge of the “cliff ” between the checkerboard and the perceived drop. Then their mothers tried to coax them over the cliff. If the infants refused to crawl over the clear glass, it was hypothesized that they could see that the “drop” was danger- ous because they perceived depth. With few exceptions, the infants would not crawl over to their mothers, indicating that infants do indeed have depth perception. Developmen- talists do not know the precise age at which infants acquire this skill, but the visual cliff demonstrated that humans attain the abil- ity before they are able to crawl.
S E C T I O N R E V I E W Describe the development of initial infant behaviors, including ref lexes and perceptual abilities.
Wrapping Up and Moving On Delivery complications, early parental involvement, and nutritional variations all have the potential to have lasting effects on development. Although there is considerable variation in infant health worldwide, nearly all infants follow similar patterns of reflexes and early development of senses. These gains form the basis for more sophisticated physical processes, which are explored next.
Summary and Resources • Unlike in other parts of the world, in the United States most babies are delivered in
hospitals under the supervision of doctors. Expectant mothers and their partners may use various birthing methods and classes, such as Lamaze.
• Doulas and midwives, which are common outside of the United States, decreased in popularity during the advent of modern medicine, but are gradually becoming more common.
Science Source ሁ Experiments using a “visual cliff ” show that
infants experience depth perception before they begin to crawl.
Summary and Resources
• The first stage of childbirth includes dilation and effacement of the cervix. The stage culminates with transition, when the cervix opens completely and contractions peak. The involuntary contractions and the urge to push result in the delivery of the baby in the second stage. The delivery of the placenta indicates the third and final stage.
• The developmental importance of bonding just after birth is not supported by research. However, there appears to be no question that both the physical health of pregnant mothers and their emotional health during the postpartum period can have a significant effect on childhood development.
• SIDS, the biggest killer of postneonatal infants, occurs during the sleep state. Some research suggests that cosleeping may reduce the incidence of SIDS as well as pro- vide a more nurturing environment for infants. However, some organizations are concerned about the potential pitfalls of cosleeping.
• The debate over breast versus formula feeding has received more attention in recent years as WHO and AAP have issued definitive recommendations that mothers should breastfeed whenever possible.
• Fairly regular infant states of arousal give clues to researchers about how the behav- ior and nervious system of infants become increasingly integrated.
• Infants are born with a number of automatic responses (reflexes), which transition to become voluntary within the first year of life.
• Most sensations and perceptions are quite well developed at birth, and others, like vision, progress rapidly.
Key Terms anoxia Oxygen deprivation.
Apgar scale A scale used to assess the ini- tial responses of newborns.
bonding The connection that occurs when one human feels emotionally close to another.
breech position When the baby is posi- tioned feet or buttocks first, making a vagi- nal delivery dangerous.
cesarean section (C-section) A surgical procedure for removing a baby through an incision in the abdomen.
contractions The contractions of the muscles of the uterus that force the fetus through the birth canal.
cosleeping Sharing a bed.
crowning The appearance of the baby’s head through the birth canal.
depth perception The ability to perceive distance and see in three dimensions.
dilation The enlargement of the cer- vix to allow the fetus to pass through the birth canal.
dishabituation An increase in the arousal to a stimulus that previously showed habituation.
doulas Caregivers who provide educational and emotional support for pregnant women.
effacement A thinning of the cervix prior to birth that allows the baby to pass through the birth canal.
extremely-low-birth-weight infants Infants who weigh less than 2.2 pounds (1,000 grams) at birth.
habituation A decrease in response to a stimulus after its repeated presentation.
low-birth-weight infants Infants who weigh less than 5.5 pounds (2,500 grams) at birth.
Summary and Resources
midwives Birthing assistants who are trained to take care of pregnant women throughout pregnancy and the birth process.
neonate The term for an infant up to 1-month postpartum.
nonorganic failure to thrive Infants who stop growing for reasons other than bio- logical (organic) ones; often due to lack of emotional support and stimulation.
perception The interpretation of stimuli through the senses.
postpartum depression A potentially serious mental disorder characterized by symptoms of clinical depression after having a child.
preterm infants Infants born prior to 37 weeks gestation; also known as preemies.
reflex An automatic physical response.
sensations The activation of nerves by certain stimuli.
small-for-date infants Infants who weigh less than 90% of infants of the same gesta- tional age.
states of arousal Physiological and psycho- logical states of awareness.
sudden infant death syndrome (SIDS) The sudden unexplained death of a healthy infant that occurs while the infant is sleep- ing. Also known as crib death.
transition The end of the first stage of labor, when the cervix is fully dilated.
very-low-birth-weight infants Infants who weigh less than 3.31 pounds (1,500 grams) at birth.
Web Resources HypnoBirthing
http://www.youtube.com/watch?v=O7kA3PMJwA8
SIDS Prevention
• AAP Task Force http://pediatrics.aappublications.org/content/early/2011/10/12/peds.2011-2284. full.pdf+html
• U.K. Department of Health http://www.patient.co.uk/health/reducing-the-risk-of-cot-death
• UNICEF UK Baby Friendly Initiative Statement http://www.unicef.org.uk/BabyFriendly/News-and-Research/News/ UNICEF-UK-Baby-Friendly-Initiative-statement-on-new-bed-sharing-research/
Visual Cliff
http://www.youtube.com/watch?v=1VPaBcT1KdY&feature=related
