12: Development
Chapter Outline
Welcome to the story of your life. In this chapter we explore the fascinating tale of how you have grown and developed into the person you are today. We also look at some ideas about who you will grow into tomorrow.
The process of human growth and development is more obvious in infancy and childhood, yet your development is happening this moment and will continue, minute by minute, for the rest of your life. Who you are today and who you will be in the future depends on a blend of genetics, environment, culture, relationships, and more, as you continue through each phase of life. You have experienced firsthand much of what is discussed in this chapter. Did you know when you were developing? What is development, and how is it different from other types of psychological change? How did you come to know what you know and think like you think? How did you form the kinds of relationships that you have or come to have your personality?
Exploring Development
By the end of this section, you will be able to:
- Define and distinguish between the three domains of development: physical, cognitive and psychosocial
- Appreciate the different approaches to developmental psychology: child psychology, lifespan psychology, and the study of systemic change
- Discuss the normative approach to development
- Understand the three major issues in development: continuity and discontinuity, one common course of development or many unique courses of development, and nature versus nurture
My heart leaps up when I behold
A rainbow in the sky:
So was it when my life began;
So is it now I am a man;
So be it when I shall grow old,
Or let me die!
The Child is father of the Man;
I could wish my days to be
Bound each to each by natural piety. (Wordsworth, 1802)
In this poem, William Wordsworth writes, “the child is father of the man.” What does this seemingly incongruous statement mean, and what does it have to do with developmental psychology? Wordsworth might be suggesting that the person he is as an adult depends largely on the experiences he had in childhood. Consider the following questions: To what extent is the adult you are today influenced by the child you once were? To what extent is a child fundamentally different from the adult he grows up to be? In what ways to we stay the same? And how do we continue changing even into old age?
Developmental psychology focuses on some of the questions that have stimulated philosophical debate since ancient times, and any field of psychological study can take a developmental perspective. Some questions will be considered later as evolutionary psychology and comparative psychology focus on what make humans similar and different from other animals and the role of language as a specifically human ability is examined. Often, child psychology is the focus as we consider how children are different from adults and what is normal for different ages. Lifespan development gained greater recognition as Erik Erikson and others focused on what was normal change for adults. A third approach also exists that considers developmental change more broadly with questions about when systematic change is and is not possible, how different psychological trajectories unfold, and what supports can facilitate meaningful change, regardless of age. Development can refer to normal, age-related thinking and behavior and to questions about the process of change that leads to systemic differences in thinking and behaving. Once upon a time, you did not know that 2 + 2 = 4, but can you ever not know it now?
These are the types of questions developmental psychologists try to answer, by studying how humans change and grow from conception through childhood, adolescence, adulthood, and death. They view development as a lifelong process that can be studied scientifically across three developmental domains—physical, cognitive, and psychosocial development. Physical development involves growth and changes in the body and brain, the senses, motor skills, and health and wellness. Cognitive development involves learning, attention, memory, language, thinking, reasoning, and creativity. Psychosocial development involves emotions, personality, and social relationships. We refer to these domains throughout the chapter.
CONNECT THE CONCEPTS: Research Methods in Developmental Psychology
You’ve learned about a variety of research methods used by psychologists. Developmental psychologists use many of these approaches in order to better understand how individuals change mentally and physically over time. These methods include naturalistic observations, case studies, surveys, and experiments, among others.
Naturalistic observations involve observing behavior in its natural context. A developmental psychologist might observe how children behave on a playground, at a daycare center, or in the child’s own home. While this research approach provides a glimpse into how children behave in their natural settings, researchers have very little control over the types and/or frequencies of displayed behavior.
In a case study, developmental psychologists collect a great deal of information from one individual in order to better understand physical and psychological changes over the lifespan. This particular approach is an excellent way to better understand individuals, who are exceptional in some way, but it is especially prone to researcher bias in interpretation, and it is difficult to generalize conclusions to the larger population. In one classic example of this research method being applied to a study of lifespan development Sigmund Freud analyzed the development of a child known as “Little Hans” (Freud, 1909/1949). Freud’s findings helped inform his theories of psychosexual development in children, which you will learn about later in this chapter.
The survey method asks individuals to self-report important information about their thoughts, experiences, and beliefs. This particular method can provide large amounts of information in relatively short amounts of time; however, validity of data collected in this way relies on honest self-reporting, and the data is relatively shallow when compared to the depth of information collected in a case study. An example of comprehensive survey was the research done by Ruth W. Howard. In 1947, she obtained her doctorate by surveying 229 sets of triplets, the most comprehensive research of triplets completed at the time. This pioneering woman was also the first African-American woman to earn a PhD in psychology (American Psychological Association, 2019).
Experiments involve significant control over extraneous variables and manipulation of the independent variable. As such, experimental research allows developmental psychologists to make causal statements about certain variables that are important for the developmental process. Because experimental research must occur in a controlled environment, researchers must be cautious about whether behaviors observed in the laboratory translate to an individual’s natural environment.
The way time influences the design of a study is particular to developmental psychology. As described in the Psychological Research Chapter, longitudinal studies follow participants over time, sometimes many years, to collect data to show how they change. By contrast, cross-sectional studies collect data from participants from different ages or stages. Because both designs can have problems with cohort effects, a cross-sequential design selects participants at different times to follow across the relevant age span. There are additional combinations of longitudinal and cross-sectional methods in an effort to reduce cohort effects as well as the problems of time, cost, and loss of participants.
Later in this chapter, you will learn about several experiments in which toddlers and young children observe scenes or actions so that researchers can determine at what age specific cognitive abilities develop. For example, children may observe a quantity of liquid poured from a short, fat glass into a tall, skinny glass. As the experimenters question the children about what occurred, the subjects’ answers help psychologists understand at what age a child begins to comprehend that the volume of liquid remained the same although the shapes of the containers differs.
Across these three domains—physical, cognitive, and psychosocial—the normative approach to development is also discussed. This approach asks, “What is normal development?” In the early decades of the 20th century, normative psychologists studied large numbers of children at various ages to determine norms (i.e., average ages) of when most children reach specific developmental milestones in each of the three domains (Gesell, 1933, 1939, 1940; Gesell & Ilg, 1946; Hall, 1904). Although children develop at slightly different rates, we can use these age-related averages as general guidelines to compare children with same-age peers to determine the approximate ages they should reach specific normative events called developmental milestones (e.g., crawling, walking, writing, dressing, naming colors, speaking in sentences, and starting puberty).
Not all normative events are universal, meaning they are not experienced by all individuals across all cultures. Biological milestones, such as puberty, tend to be universal, but social milestones, such as the age when children begin formal schooling, are not necessarily universal; instead, they affect most individuals in a particular culture (Gesell & Ilg, 1946). For example, in developed countries children begin school around 5 or 6 years old, but in developing countries, like Nigeria, children often enter school at an advanced age, if at all (Huebler, 2005; United Nations Educational, Scientific, and Cultural Organization [UNESCO], 2013).
To better understand the normative approach, imagine two new mothers, Louisa and Kimberly, who are close friends and have children around the same age. Louisa’s daughter is 14 months old, and Kimberly’s son is 12 months old. According to the normative approach, the average age a child starts to walk is 12 months. However, at 14 months Louisa’s daughter still isn’t walking. She tells Kimberly she is worried that something might be wrong with her baby. Kimberly is surprised because her son started walking when he was only 10 months old. Should Louisa be worried? Should she be concerned if her daughter is not walking by 15 months or 18 months?
Issues in Developmental Psychology
There are many different theoretical approaches regarding human development. As we evaluate them in this chapter, recall that developmental psychology focuses on how people change, and keep in mind that all the approaches that we present in this chapter address questions of change: Is the change smooth or uneven (continuous versus discontinuous)? Is this pattern of change the same for everyone, or are there many different patterns of change (one course of development versus many courses)? How do genetics and environment interact to influence development (nature versus nurture)?
Is Development Continuous or Discontinuous?
Continuous development views development as a cumulative process, gradually improving on existing skills (Figure 12.2). With this type of development, there is gradual change. Consider, for example, a child’s physical growth: adding inches to height year by year. In contrast, theorists who view development as discontinuous believe that development takes place in unique stages: It occurs at specific times or ages. With this type of development, the change is more sudden, such as an infant’s ability to conceive object permanence.
Is development essentially the same, or universal, for all children (i.e., there is one course of development) or does development follow a different course for each child, depending on the child’s specific genetics and environment (i.e., there are many courses of development)? Do people across the world share more similarities or more differences in their development? How much do culture and genetics influence a child’s behavior?
Stage theories hold that the sequence of development is universal. For example, in cross-cultural studies of language development, children from around the world reach language milestones in a similar sequence (Gleitman & Newport, 1995). Infants in all cultures coo before they babble. They begin babbling at about the same age and utter their first word around 12 months old. Yet we live in diverse contexts that have a unique effect on each of us. For example, researchers once believed that motor development follows one course for all children regardless of culture. However, child care practices vary by culture, and different practices have been found to accelerate or inhibit achievement of developmental milestones such as sitting, crawling, and walking (Karasik, Adolph, Tamis-LeMonda, & Bornstein, 2010).
For instance, let’s look at the Aché society in Paraguay. They spend a significant amount of time foraging in forests. While foraging, Aché mothers carry their young children, rarely putting them down in order to protect them from getting hurt in the forest. Consequently, their children walk much later: They walk around 23–25 months old, in comparison to infants in Western cultures who begin to walk around 12 months old. However, as Aché children become older, they are allowed more freedom to move about, and by about age 9, their motor skills surpass those of U.S. children of the same age: Aché children are able to climb trees up to 25 feet tall and use machetes to chop their way through the forest (Kaplan & Dove, 1987). As you can see, our development is influenced by multiple contexts, so the timing of basic motor functions may vary across cultures. However, the functions themselves are present in all societies (Figure 12.3).
Are we who we are because of nature (biology and genetics), or are we who we are because of nurture (our environment and culture)? This longstanding question is known in psychology as the nature versus nurture debate. It seeks to understand how our personalities and traits are the product of our genetic makeup and biological factors, and how they are shaped by our environment, including our parents, peers, and culture. For instance, why do biological children sometimes act like their parents—is it because of genetics or because of early childhood environment and what the child has learned from the parents? What about children who are adopted—are they more like their biological families or more like their adoptive families? And how can siblings from the same family be so different?
We are all born with specific genetic traits inherited from our parents, such as eye color, height, and certain personality traits. Beyond our basic genotype, however, there is a deep interaction between our genes and our environment: Our unique experiences in our environment influence whether and how particular traits are expressed, and at the same time, our genes influence how we interact with our environment (Diamond, 2009; Lobo, 2008). This chapter will show that there is a reciprocal interaction between nature and nurture as they both shape who we become, but the debate continues as to the relative contributions of each.
DIG DEEPER: The Achievement Gap: How Does Socioeconomic Status Affect Development?
The achievement gap refers to the persistent difference in grades, test scores, and graduation rates that exist among students of different ethnicities, races, and—in certain subjects—sexes (Winerman, 2011). Research suggests that these achievement gaps are strongly influenced by differences in socioeconomic factors that exist among the families of these children. While the researchers acknowledge that programs aimed at reducing such socioeconomic discrepancies would likely aid in equalizing the aptitude and performance of children from different backgrounds, they recognize that such large-scale interventions would be difficult to achieve. Therefore, it is recommended that programs aimed at fostering aptitude and achievement among disadvantaged children may be the best option for dealing with issues related to academic achievement gaps (Duncan & Magnuson, 2005).
Low-income children perform significantly more poorly than their middle- and high-income peers on a number of educational variables: They have significantly lower standardized test scores, graduation rates, and college entrance rates, and they have much higher school dropout rates. There have been attempts to correct the achievement gap through state and federal legislation, but what if the problems start before the children even enter school?
Psychologists Betty Hart and Todd Risley (2006) spent their careers looking at early language ability and progression of children in various income levels. In one longitudinal study, they found that although all the parents in the study engaged and interacted with their children, middle- and high-income parents interacted with their children differently than low-income parents. After analyzing 1,300 hours of parent-child interactions, the researchers found that middle- and high-income parents talk to their children significantly more, starting when the children are infants. By 3 years old, high-income children knew almost double the number of words known by their low-income counterparts, and they had heard an estimated total of 30 million more words than the low-income counterparts (Hart & Risley, 2003). And the gaps only become more pronounced. Before entering kindergarten, high-income children score 60% higher on achievement tests than their low-income peers (Lee & Burkam, 2002).
There are solutions to this problem. At the University of Chicago, experts are working with low-income families, visiting them at their homes, and encouraging them to speak more to their children on a daily and hourly basis. Other experts are designing preschools in which students from diverse economic backgrounds are placed in the same classroom. In this research, low-income children made significant gains in their language development, likely as a result of attending the specialized preschool (Schechter & Byeb, 2007). What other methods or interventions could be used to decrease the achievement gap? What types of activities could be implemented to help the children of your community or a neighboring community?
Genetics & the Nature-Nurture Debate
By the end of this section, you will be able to:
- Explain the basic principles of the theory of evolution by natural selection
- Describe the differences between genotype and phenotype
- Discuss how gene-environment interactions are critical for expression of physical and psychological characteristics
Psychological researchers study genetics in order to better understand the biological factors that contribute to certain behaviors. While all humans share certain biological mechanisms, we are each unique. And while our bodies have many of the same parts—brains and hormones and cells with genetic codes—these are expressed in a wide variety of behaviors, thoughts, and reactions.
Why do two people infected by the same disease have different outcomes: one surviving and one succumbing to the ailment? How are genetic diseases passed through family lines? Are there genetic components to psychological disorders, such as depression or schizophrenia? To what extent might there be a psychological basis to health conditions such as childhood obesity?
To explore these questions, let’s start by focusing on a specific genetic disorder, sickle cell anemia, and how it might manifest in two affected sisters. Sickle-cell anemia is a genetic condition in which red blood cells, which are normally round, take on a crescent-like shape (Figure 12.4). The changed shape of these cells affects how they function: sickle-shaped cells can clog blood vessels and block blood flow, leading to high fever, severe pain, swelling, and tissue damage.
Imagine two young women—Luwi and Sena—sisters in rural Zambia, Africa. Luwi carries the gene for sickle-cell anemia; Sena does not carry the gene. Sickle-cell carriers have one copy of the sickle-cell gene but do not have full-blown sickle-cell anemia. They experience symptoms only if they are severely dehydrated or are deprived of oxygen (as in mountain climbing). Carriers are thought to be immune from malaria (an often deadly disease that is widespread in tropical climates) because changes in their blood chemistry and immune functioning prevent the malaria parasite from having its effects (Gong, Parikh, Rosenthal, & Greenhouse, 2013). However, full-blown sickle-cell anemia, with two copies of the sickle-cell gene, does not provide immunity to malaria.
While walking home from school, both sisters are bitten by mosquitos carrying the malaria parasite. Luwi is protected against malaria because she carries the sickle-cell mutation. Sena, on the other hand, develops malaria and dies just two weeks later. Luwi survives and eventually has children, to whom she may pass on the sickle-cell mutation.
Malaria is rare in the United States, so the sickle-cell gene benefits nobody: the gene manifests primarily in minor health problems for carriers with one copy, or a severe full-blown disease with no health benefits for carriers with two copies. However, the situation is quite different in other parts of the world. In parts of Africa where malaria is prevalent, having the sickle-cell mutation does provide health benefits for carriers (protection from malaria).
The story of malaria fits with Charles Darwin’s theory of evolution by natural selection (Figure 12.5). In simple terms, the theory states that organisms that are better suited for their environment will survive and reproduce, while those that are poorly suited for their environment will die off. In our example, we can see that, as a carrier, Luwi’s mutation is highly adaptive in her African homeland; however, if she resided in the United States (where malaria is rare), her mutation could prove costly—with a high probability of the disease in her descendants and minor health problems of her own.
DIG DEEPER: Two Perspectives on Genetics and Behavior
It’s easy to get confused about two fields that study the interaction of genes and the environment, such as the fields of evolutionary psychology and behavioral genetics. How can we tell them apart?
In both fields, it is understood that genes not only code for particular traits, but also contribute to certain patterns of cognition and behavior. Evolutionary psychology focuses on how universal patterns of behavior and cognitive processes have evolved over time. Therefore, variations in cognition and behavior would make individuals more or less successful in reproducing and passing those genes on to their offspring. Evolutionary psychologists study a variety of psychological phenomena that may have evolved as adaptations, including fear response, food preferences, mate selection, and cooperative behaviors (Confer et al., 2010).
Whereas evolutionary psychologists focus on universal patterns that evolved over millions of years, behavioral geneticists study how individual differences arise, in the present, through the interaction of genes and the environment. When studying human behavior, behavioral geneticists often employ twin and adoption studies to research questions of interest. Twin studies compare the likelihood that a given behavioral trait is shared among identical and fraternal twins; adoption studies compare those rates among biologically related relatives and adopted relatives. Both approaches provide some insight into the relative importance of genes and environment for the expression of a given trait.
Genetic variation, the genetic difference between individuals, is what contributes to a species’ adaptation to its environment. In humans, genetic variation begins with an egg, about 100 million sperm, and fertilization. Fertile women ovulate roughly once per month, releasing an egg from follicles in the ovary. During the egg’s journey from the ovary through the fallopian tubes, to the uterus, a sperm may fertilize the egg.
The egg and the sperm each contain 23 chromosomes. Chromosomes are long strings of genetic material known as deoxyribonucleic acid (DNA). DNA is a helix-shaped molecule made up of nucleotide base pairs. In each chromosome, sequences of DNA make up genes that control or partially control a number of visible characteristics, known as traits, such as eye color, hair color, and so on. A single gene may have multiple possible variations, or alleles. An allele is a specific version of a gene. So, a given gene may code for the trait of hair color, and the different alleles of that gene affect which hair color an individual has.
When a sperm and egg fuse, their 23 chromosomes combine to create a zygote with 46 chromosomes (23 pairs). Therefore, each parent contributes half the genetic information carried by the offspring; the resulting physical characteristics of the offspring (called the phenotype) are determined by the interaction of genetic material supplied by the parents (called the genotype). A person’s genotype is the genetic makeup of that individual. Phenotype, on the other hand, refers to the individual’s inherited physical characteristics, which are a combination of genetic and environmental influences (Figure 12.6).
Imagine that a woman with a cleft chin mates with a man with a smooth chin. What type of chin will their child have? The answer to that depends on which alleles each parent carries. If the woman is homozygous for cleft chin (BB), her offspring will always have cleft chin. It gets a little more complicated, however, if the mother is heterozygous for this gene (Bb). Since the father has a smooth chin—therefore homozygous for the recessive allele (bb)—we can expect the offspring to have a 50% chance of having a cleft chin and a 50% chance of having a smooth chin (Figure 12.7).
So far, we have discussed traits that involve just one gene, but few human characteristics are controlled by a single gene. Most traits are polygenic: controlled by more than one gene. Height is one example of a polygenic trait, as are skin color and weight.
Where do harmful genes that contribute to diseases like PKU come from? Gene mutations provide one source of harmful genes. A mutation is a sudden, permanent change in a gene. While many mutations can be harmful or lethal, once in a while, a mutation benefits an individual by giving that person an advantage over those who do not have the mutation. Recall that the theory of evolution asserts that individuals best adapted to their particular environments are more likely to reproduce and pass on their genes to future generations. In order for this process to occur, there must be competition—more technically, there must be variability in genes (and resultant traits) that allow for variation in adaptability to the environment. If a population consisted of identical individuals, then any dramatic changes in the environment would affect everyone in the same way, and there would be no variation in selection. In contrast, diversity in genes and associated traits allows some individuals to perform slightly better than others when faced with environmental change. This creates a distinct advantage for individuals best suited for their environments in terms of successful reproduction and genetic transmission.
DIG DEEPER: Human Diversity
When we focus strictly on biology, race becomes a weak construct. After the sequencing of the human genome at the turn of the millennium, many scientists began to argue that race was not a useful variable in genetic research and that its continued use represents a potential source of confusion and harm. The racial categories that some believed to be helpful in studying genetic diversity in humans are largely irrelevant. A person’s skin tone, eye color, and hair texture are functions of their genetic makeups, but there is actually more genetic variation within a given racial category than there is between racial categories. In some cases, focus on race has led to difficulties with misdiagnoses and/or under-diagnoses of diseases ranging from sickle cell anemia to cystic fibrosis. Some argue that we need to distinguish between ancestry and race and then focus on ancestry. This approach would facilitate greater understanding of human genetic diversity (Yudell, Roberts, DeSalle, & Tishkoff, 2016). In the end, we should recognize that race is a social construct without out any scientific basis, even as it continues to have social meaning.
Gene-Environment Interactions
Genes do not exist in a vacuum. Although we are all biological organisms, we also exist in an environment that is incredibly important in determining not only when and how our genes express themselves, but also in what combination. Each of us represents a unique interaction between our genetic makeup and our environment; range of reaction is one way to describe this interaction. Range of reaction asserts that our genes set the boundaries within which we can operate, and our environment interacts with the genes to determine where in that range we will fall. For example, if an individual’s genetic makeup predisposes her to high levels of intellectual potential and she is reared in a rich, stimulating environment, then she will be more likely to achieve her full potential than if she were raised under conditions of significant deprivation. According to the concept of range of reaction, genes set definite limits on potential, and environment determines how much of that potential is achieved. Some disagree with this theory and argue that genes do not set a limit on a person’s potential with reaction norms being determined by the environment. For example, when individuals experience neglect or abuse early in life, they are more likely to exhibit adverse psychological and/or physical conditions that can last throughout their lives. These conditions may develop as a function of the negative environmental experiences in individuals from dissimilar genetic backgrounds (Miguel, Pereira, Silveira, & Meaney, 2019; Short & Baram, 2019).
Another perspective on the interaction between genes and the environment is the concept of genetic environmental correlation. Stated simply, our genes influence our environment, and our environment influences the expression of our genes (Figure 12.9). Not only do our genes and environment interact, as in range of reaction, but they also influence one another bidirectionally. For example, the child of an NBA player would probably be exposed to basketball from an early age. Such exposure might allow the child to realize his or her full genetic, athletic potential. Thus, the parents’ genes, which the child shares, influence the child’s environment, and that environment, in turn, is well suited to support the child’s genetic potential.
Genes affect more than our physical characteristics. Indeed, scientists have found genetic linkages to a number of behavioral characteristics, ranging from basic personality traits to sexual orientation to spirituality (for examples, see Mustanski et al., 2005; Comings, Gonzales, Saucier, Johnson, & MacMurray, 2000). Genes are also associated with temperament and a number of psychological disorders, such as depression and schizophrenia. So while it is true that genes provide the biological blueprints for our cells, tissues, organs, and body, they also have a significant impact on our experiences and our behaviors.
Let’s look at the following findings regarding schizophrenia in light of our three views of gene-environment interactions. Which view do you think best explains this evidence?
In a 2004 study by Tienari and colleagues, of people who were given up for adoption, adoptees whose biological mothers had schizophrenia and who had been raised in a disturbed family environment were much more likely to develop schizophrenia or another psychotic disorder than were any of the other groups in the study:
- Of adoptees whose biological mothers had schizophrenia (high genetic risk) and who were raised in disturbed family environments, 36.8% were likely to develop schizophrenia.
- Of adoptees whose biological mothers had schizophrenia (high genetic risk) and who were raised in healthy family environments, 5.8% were likely to develop schizophrenia.
- Of adoptees with a low genetic risk (whose mothers did not have schizophrenia) and who were raised in disturbed family environments, 5.3% were likely to develop schizophrenia.
- Of adoptees with a low genetic risk (whose mothers did not have schizophrenia) and who were raised in healthy family environments, 4.8% were likely to develop schizophrenia.
The study shows that adoptees with high genetic risk were most likely to develop schizophrenia if they were raised in disturbed home environments. This research lends credibility to the notion that both genetic vulnerability and environmental stress are necessary for schizophrenia to develop, and that genes alone do not tell the full tale.
Lifespan Development
By the end of this section, you will be able to:
- Describe the stages of prenatal development and recognize the importance of prenatal care
- Appraise physical, cognitive, and emotional development that occurs from infancy through childhood
- Compare and contrast physical, cognitive, and emotional development that occurs during adolescence
- Examine physical, cognitive, and emotional development that occurs in adulthood
From the moment we are born until the moment we die, we continue to develop. By approaching psychological development with a lifespan perspective, psychologists attempt to understand how particular developmental changes are associated with particular times of life. Mirroring Erikson’s stages, lifespan development is divided into different stages that are based on age. We will discuss a broad range of physical, cognitive, and socioemotional issues associated with prenatal, infant, child, adolescent, and adult development. In the following two sections, we will specifically consider theories that focus on discontinuous development or stages and then continuous development to focus on some theoretical differences.
Prenatal Development
How did you come to be who you are? From beginning as a one-cell structure to your birth, your prenatal development occurred in an orderly and delicate sequence. There are three stages of prenatal development: germinal, embryonic, and fetal. Let’s take a look at what happens to the developing baby in each of these stages.
Germinal Stage (Weeks 1–2)
In the discussion of biopsychology earlier in the book, you learned about genetics and DNA. A mother and father’s DNA is passed on to the child at the moment of conception. Conception occurs when sperm fertilizes an egg and forms a zygote (Figure 12.10). A zygote begins as a one-cell structure that is created when a sperm and egg merge. The genetic makeup and sex of the baby are set at this point. During the first week after conception, the zygote divides and multiplies, going from a one-cell structure to two cells, then four cells, then eight cells, and so on. This process of cell division is called mitosis. Mitosis is a fragile process, and fewer than one-half of all zygotes survive beyond the first two weeks (Hall, 2004). After 5 days of mitosis there are 100 cells, and after 9 months there are billions of cells. As the cells divide, they become more specialized, forming different organs and body parts. In the germinal stage, the mass of cells has yet to attach itself to the lining of the mother’s uterus. Once it does, the next stage begins.
Embryonic Stage (Weeks 3–8)
After the zygote divides for about 7–10 days and has 150 cells, it travels down the fallopian tubes and implants itself in the lining of the uterus. Upon implantation, this multi-cellular organism is called an embryo. Now blood vessels grow, forming the placenta. The placenta is a structure connected to the uterus that provides nourishment and oxygen from the mother to the developing embryo via the umbilical cord. Basic structures of the embryo start to develop into areas that will become the head, chest, and abdomen. During the embryonic stage, the heart begins to beat and organs form and begin to function. The neural tube forms along the back of the embryo, developing into the spinal cord and brain.
Fetal Stage (Weeks 9–40)
When the organism is about nine weeks old, the embryo is called a fetus. At this stage, the fetus is about the size of a kidney bean and begins to take on the recognizable form of a human being as the “tail” begins to disappear.
From 9–12 weeks, the sex organs begin to differentiate. At about 16 weeks, the fetus is approximately 4.5 inches long. Fingers and toes are fully developed, and fingerprints are visible. By the time the fetus reaches the sixth month of development (24 weeks), it weighs up to 1.4 pounds. Hearing has developed, so the fetus can respond to sounds. The internal organs, such as the lungs, heart, stomach, and intestines, have formed enough that a fetus born prematurely at this point has a chance to survive outside of the mother’s womb. Throughout the fetal stage the brain continues to grow and develop, nearly doubling in size from weeks 16 to 28. Around 36 weeks, the fetus is almost ready for birth. It weighs about 6 pounds and is about 18.5 inches long, and by week 37 all of the fetus’s organ systems are developed enough that it could survive outside the mother’s uterus without many of the risks associated with premature birth. The fetus continues to gain weight and grow in length until approximately 40 weeks. By then, the fetus has very little room to move around and birth becomes imminent. The progression through the stages is shown in Figure 12.11.
Prenatal Influences
During each prenatal stage, genetic and environmental factors can affect development. The developing fetus is completely dependent on the mother for life. It is important that the mother takes good care of herself and receives prenatal care, which is medical care during pregnancy that monitors the health of both the mother and the fetus (Figure 12.12). According to the National Institutes of Health ([NIH], 2013), routine prenatal care is important because it can reduce the risk of complications to the mother and fetus during pregnancy. In fact, women who are trying to become pregnant or who may become pregnant should discuss pregnancy planning with their doctor. They may be advised, for example, to take a vitamin containing folic acid, which helps prevent certain birth defects, or to monitor aspects of their diet or exercise routines.
A teratogen is any environmental agent—biological, chemical, or physical—that causes damage to the developing embryo or fetus. There are different types of teratogens. Alcohol and most drugs cross the placenta and affect the fetus. Alcohol is not safe to drink in any amount during pregnancy. Alcohol use during pregnancy has been found to be the leading preventable cause of mental retardation in children in the United States (Maier & West, 2001). Excessive maternal drinking while pregnant can cause fetal alcohol spectrum disorders with life-long consequences for the child ranging in severity from minor to major (Table 12.1). Fetal alcohol spectrum disorders (FASD) are a collection of birth defects associated with heavy consumption of alcohol during pregnancy. Physically, children with FASD may have a small head size and abnormal facial features. Cognitively, these children may have poor judgment, poor impulse control, higher rates of ADHD, learning issues, and lower IQ scores. These developmental problems and delays persist into adulthood (Streissguth et al., 2004). Based on studies conducted on animals, it also has been suggested that a mother’s alcohol consumption during pregnancy may predispose her child to like alcohol (Youngentob et al., 2007).
| Table 12.1: Fetal Alcohol Syndrome Facial Features | |
|---|---|
| Facial Feature | Potential Effect of Fetal Alcohol Syndrome |
| Head size | Below-average head circumference |
| Eyes | Smaller than average eye opening, skin folds at corners of eyes |
| Nose | Low nasal bridge, short nose |
| Midface | Smaller than average midface size |
| Lip and philtrum | Thin upper lip, indistinct philtrum |
Heroin, cocaine, methamphetamine, almost all prescription medicines, and most over-the counter medications are also considered teratogens. Babies born with a heroin addiction need heroin just like an adult addict. The child will need to be gradually weaned from the heroin under medical supervision; otherwise, the child could have seizures and die. Other teratogens include radiation, viruses such as HIV and herpes, and rubella (German measles). Women in the United States are much less likely to be afflicted with rubella because most women received childhood immunizations or vaccinations that protect the body from disease.
Each organ of the fetus develops during a specific period in the pregnancy, called the critical or sensitive period (Figure 12.11). For example, research with primate models of FASD has demonstrated that the time during which a developing fetus is exposed to alcohol can dramatically affect the appearance of facial characteristics associated with fetal alcohol syndrome. Specifically, this research suggests that alcohol exposure that is limited to day 19 or 20 of gestation can lead to significant facial abnormalities in the offspring (Ashley, Magnuson, Omnell, & Clarren, 1999). Given regions of the brain also show sensitive periods during which they are most susceptible to the teratogenic effects of alcohol (Tran & Kelly, 2003).
WHAT DO YOU THINK? Should Women Who Use Drugs During Pregnancy Be Arrested and Jailed?
As you now know, women who use drugs or alcohol during pregnancy can cause serious lifelong harm to their child. Some people have advocated mandatory screenings for women who are pregnant and have a history of drug abuse, and if the women continue using, to arrest, prosecute, and incarcerate them (Figdor & Kaeser, 1998). This policy was tried in Charleston, South Carolina, as recently as 20 years ago. The policy was called the Interagency Policy on Management of Substance Abuse During Pregnancy, and had disastrous results.
The Interagency Policy applied to patients attending the obstetrics clinic at MUSC, which primarily serves patients who are indigent or on Medicaid. It did not apply to private obstetrical patients. The policy required patient education about the harmful effects of substance abuse during pregnancy. . . . [A] statement also warned patients that protection of unborn and newborn children from the harms of illegal drug abuse could involve the Charleston police, the Solicitor of the Ninth Judicial Court, and the Protective Services Division of the Department of Social Services (DSS). (Jos, Marshall, & Perlmutter, 1995, pp. 120–121)
This policy seemed to deter women from seeking prenatal care, deterred them from seeking other social services, and was applied solely to low-income women, resulting in lawsuits. The program was canceled after 5 years, during which 42 women were arrested. A federal agency later determined that the program involved human experimentation without the approval and oversight of an institutional review board (IRB). What were the flaws in the program and how would you correct them? What are the ethical implications of charging pregnant women with child abuse?
Infancy Through Childhood
The average newborn weighs approximately 7.5 pounds. Although small, a newborn is not completely helpless because his reflexes and sensory capacities help him interact with the environment from the moment of birth. All healthy babies are born with newborn reflexes: inborn automatic responses to particular forms of stimulation. Reflexes help the newborn survive until it is capable of more complex behaviors—these reflexes are crucial to survival. They are present in babies whose brains are developing normally and usually disappear around 4–5 months old. Let’s take a look at some of these newborn reflexes. The rooting reflex is the newborn’s response to anything that touches her cheek: When you stroke a baby’s cheek, she naturally turns her head in that direction and begins to suck. The sucking reflex is the automatic, unlearned, sucking motions that infants do with their mouths. Several other interesting newborn reflexes can be observed. For instance, if you put your finger into a newborn’s hand, you will witness the grasping reflex, in which a baby automatically grasps anything that touches his palms. The Moro reflex is the newborn’s response when she feels like she is falling. The baby spreads her arms, pulls them back in, and then (usually) cries. How do you think these reflexes promote survival in the first months of life?
What can young infants see, hear, and smell? Newborn infants’ sensory abilities are significant, but their senses are not yet fully developed. Many of a newborn’s innate preferences facilitate interaction with caregivers and other humans. Although vision is their least developed sense, newborns already show a preference for faces. Babies who are just a few days old also prefer human voices, they will listen to voices longer than sounds that do not involve speech (Vouloumanos & Werker, 2004), and they seem to prefer their mother’s voice over a stranger’s voice (Mills & Melhuish, 1974). In an interesting experiment, 3-week-old babies were given pacifiers that played a recording of the infant’s mother’s voice and of a stranger’s voice. When the infants heard their mother’s voice, they sucked more strongly at the pacifier (Mills & Melhuish, 1974). Newborns also have a strong sense of smell. For instance, newborn babies can distinguish the smell of their own mother from that of others. In a study by MacFarlane (1978), 1-week-old babies who were being breastfed were placed between two gauze pads. One gauze pad was from the bra of a nursing mother who was a stranger, and the other gauze pad was from the bra of the infant’s own mother. More than two-thirds of the week-old babies turned toward the gauze pad with their mother’s scent.
In infancy, toddlerhood, and early childhood, the body’s physical development is rapid (Figure 12.13). On average, newborns weigh between 5 and 10 pounds, and a newborn’s weight typically doubles in six months and triples in one year. By 2 years old the weight will have quadrupled, so we can expect that a 2 year old should weigh between 20 and 40 pounds. The average length of a newborn is 19.5 inches, increasing to 29.5 inches by 12 months and 34.4 inches by 2 years old (WHO Multicentre Growth Reference Study Group, 2006).
There has been debate about whether or not new neurons come into being after birth, called neurogenesis; researchers were certain that there was no neurogenesis, but evidence in non-human animals suggests that new neurons arise in the hippocampus at least during childhood (Weiler, 2018). It is clear that new neurons are relatively rare, yet the nervous system continues to grow and develop. Each neural pathway forms thousands of new connections during infancy and toddlerhood. This period of rapid neural growth is called blooming. Neural pathways continue to develop through puberty. The blooming period of neural growth is then followed by a period of pruning, where neural connections are reduced. It is thought that pruning causes the brain to function more efficiently, allowing for mastery of more complex skills (Hutchinson, 2011). Blooming occurs during the first few years of life, and pruning continues through childhood and into adolescence in various areas of the brain.
The size of our brains increases rapidly. For example, the brain of a 2-year-old is 55% of its adult size, and by 6 years old the brain is about 90% of its adult size (Tanner, 1978). During early childhood (ages 3–6), the frontal lobes grow rapidly. Recalling our discussion of the 4 lobes of the brain earlier in this book, the frontal lobes are associated with planning, reasoning, memory, and impulse control. Therefore, by the time children reach school age, they are developmentally capable of controlling their attention and behavior. Through the elementary school years, the frontal, temporal, occipital, and parietal lobes all grow in size. The brain growth spurts experienced in childhood tend to follow Piaget’s sequence of cognitive development, so that significant changes in neural functioning account for cognitive advances (Kolb & Whishaw, 2009; Overman, Bachevalier, Turner, & Peuster, 1992).
Motor development occurs in an orderly sequence as infants move from reflexive reactions (e.g., sucking and rooting) to more advanced motor functioning. For instance, babies first learn to hold their heads up, then to sit with assistance, and then to sit unassisted, followed later by crawling and then walking.
Motor skills refer to our ability to move our bodies and manipulate objects. Fine motor skills focus on the muscles in our fingers, toes, and eyes, and enable coordination of small actions (e.g., grasping a toy, writing with a pencil, and using a spoon). Gross motor skills focus on large muscle groups that control our arms and legs and involve larger movements (e.g., balancing, running, and jumping).
As motor skills develop, there are certain developmental milestones that young children should achieve (Table 12.2). For each milestone there is an average age, as well as a range of ages in which the milestone should be reached. An example of a developmental milestone is sitting. On average, most babies sit alone at 7 months old. Sitting involves both coordination and muscle strength, and 90% of babies achieve this milestone between 5 and 9 months old. In another example, babies on average are able to hold up their head at 6 weeks old, and 90% of babies achieve this between 3 weeks and 4 months old. If a baby is not holding up his head by 4 months old, he is showing a delay. If the child is displaying delays on several milestones, that is reason for concern, and the parent or caregiver should discuss this with the child’s pediatrician. Some developmental delays can be identified and addressed through early intervention.
| Table 12.2: Developmental Milestones, Ages 2–5 Years | ||||
|---|---|---|---|---|
| Age (years) | Physical | Personal/Social | Language | Cognitive |
| 2 | Kicks a ball; walks up and down stairs | Plays alongside other children; copies adults | Points to objects when named; puts 2–4 words together in a sentence | Sorts shapes and colors; follows 2-step instructions |
| 3 | Climbs and runs; pedals tricycle | Takes turns; expresses many emotions; dresses self | Names familiar things; uses pronouns | Plays make believe; works toys with parts (levers, handles) |
| 4 | Catches balls; uses scissors | Prefers social play to solo play; knows likes and interests | Knows songs and rhymes by memory | Names colors and numbers; begins writing letters |
| 5 | Hops and swings; uses fork and spoon | Distinguishes real from pretend; likes to please friends | Speaks clearly; uses full sentences | Counts to 10 or higher; prints some letters and copies basic shapes |
Attachment
Psychosocial development occurs as children form relationships, interact with others, and understand and manage their feelings. In social and emotional development, forming healthy attachments is very important and is the major social milestone of infancy. Attachment is a long-standing connection or bond with others. Developmental psychologists are interested in how infants reach this milestone. They ask such questions as: How do parent and infant attachment bonds form? How does neglect affect these bonds? What accounts for children’s attachment differences?
Researchers Harry Harlow, John Bowlby, and Mary Ainsworth conducted studies designed to answer these questions. In the 1950s, Harlow conducted a series of experiments on monkeys. He separated newborn monkeys from their mothers. Each monkey was presented with two surrogate mothers. One surrogate monkey was made out of wire mesh, and she could dispense milk. The other monkey was softer and made from cloth: This monkey did not dispense milk. Research shows that the monkeys preferred the soft, cuddly cloth monkey, even though she did not provide any nourishment. The baby monkeys spent their time clinging to the cloth monkey and only went to the wire monkey when they needed to be fed. Prior to this study, the medical and scientific communities generally thought that babies become attached to the people who provide their nourishment. However, Harlow (1958) concluded that there was more to the mother-child bond than nourishment. Feelings of comfort and security are the critical components to maternal-infant bonding, which leads to healthy psychosocial development.
Building on the work of Harlow and others, John Bowlby developed the concept of attachment theory. He defined attachment as the affectional bond or tie that an infant forms with the mother (Bowlby, 1969). An infant must form this bond with a primary caregiver in order to have normal social and emotional development. In addition, Bowlby proposed that this attachment bond is very powerful and continues throughout life. He used the concept of secure base to define a healthy attachment between parent and child (1988). A secure base is a parental presence that gives the child a sense of safety as he explores his surroundings. Bowlby said that two things are needed for a healthy attachment: The caregiver must be responsive to the child’s physical, social, and emotional needs; and the caregiver and child must engage in mutually enjoyable interactions (Bowlby, 1969) (Figure 12.14).
Based on how the infants/toddlers responded to the separation and reunion, Ainsworth identified three types of parent-child attachments: secure, avoidant, and resistant (Ainsworth & Bell, 1970). A fourth style, known as disorganized attachment, was later described (Main & Solomon, 1990). The most common type of attachment—also considered the healthiest—is called secure attachment (Figure 12.15). In this type of attachment, the toddler prefers his parent over a stranger. The attachment figure is used as a secure base to explore the environment and is sought out in times of stress. Securely attached children were distressed when their caregivers left the room in the Strange Situation experiment, but when their caregivers returned, the securely attached children were happy to see them. Securely attached children have caregivers who are sensitive and responsive to their needs.
In cases of resistant attachment, children tend to show clingy behavior, but then they reject the attachment figure’s attempts to interact with them (Ainsworth & Bell, 1970). These children do not explore the toys in the room, as they are too fearful. During separation in the Strange Situation, they became extremely disturbed and angry with the parent. When the parent returns, the children are difficult to comfort. Resistant attachment is the result of the caregivers’ inconsistent level of response to their child.
Finally, children with disorganized attachment behaved oddly in the Strange Situation. They freeze, run around the room in an erratic manner, or try to run away when the caregiver returns (Main & Solomon, 1990). This type of attachment is seen most often in kids who have been abused. Research has shown that abuse disrupts a child’s ability to regulate their emotions.
While Ainsworth’s research has found support in subsequent studies, it has also met criticism. Some researchers have pointed out that a child’s temperament may have a strong influence on attachment (Gervai, 2009; Harris, 2009), and others have noted that attachment varies from culture to culture, a factor not accounted for in Ainsworth’s research (Rothbaum, Weisz, Pott, Miyake, & Morelli, 2000; van Ijzendoorn & Sagi-Schwartz, 2008).
Adolescence
Adolescence is a socially constructed concept. In pre-industrial society, children were considered adults when they reached physical maturity, but today we have an extended time between childhood and adulthood called adolescence. Adolescence is the period of development that begins at puberty and ends at emerging adulthood, which is discussed later. In the United States, adolescence is seen as a time to develop independence from parents while remaining connected to them (Figure 12.16). The typical age range of adolescence is from 12 to 18 years, and this stage of development also has some predictable physical, cognitive, and psychosocial milestones.
During puberty, both sexes experience a rapid increase in height (i.e., growth spurt). For girls this begins between 8 and 13 years old, with adult height reached between 10 and 16 years old. Boys begin their growth spurt slightly later, usually between 10 and 16 years old, and reach their adult height between 13 and 17 years old. Both nature (i.e., genes) and nurture (e.g., nutrition, medications, and medical conditions) can influence height.
Because rates of physical development vary so widely among teenagers, puberty can be a source of pride or embarrassment. Early maturing boys tend to be stronger, taller, and more athletic than their later maturing peers. They are usually more popular, confident, and independent, but they are also at a greater risk for substance abuse and early sexual activity (Flannery, Rowe, & Gulley, 1993; Kaltiala-Heino, Rimpela, Rissanen, & Rantanen, 2001). Early maturing girls may be teased or overtly admired, which can cause them to feel self-conscious about their developing bodies. These girls are at a higher risk for depression, substance abuse, and eating disorders (Ge, Conger, & Elder, 2001; Graber, Lewinsohn, Seeley, & Brooks-Gunn, 1997; Striegel-Moore & Cachelin, 1999). Late blooming boys and girls (i.e., they develop more slowly than their peers) may feel self-conscious about their lack of physical development. Negative feelings are particularly a problem for late maturing boys, who are at a higher risk for depression and conflict with parents (Graber et al., 1997) and more likely to be bullied (Pollack & Shuster, 2000).
The adolescent brain also remains under development. Up until puberty, brain cells continue to bloom in the frontal region. Adolescents engage in increased risk-taking behaviors and emotional outbursts possibly because the frontal lobes of their brains are still developing (Figure 12.17). Recall that this area is responsible for judgment, impulse control, and planning, and it is still maturing into early adulthood (Casey, Tottenham, Liston, & Durston, 2005).
It appears that most teens don’t experience adolescent storm and stress to the degree once famously suggested by G. Stanley Hall, a pioneer in the study of adolescent development. Only small numbers of teens have major conflicts with their parents (Steinberg & Morris, 2001), and most disagreements are minor. For example, in a study of over 1,800 parents of adolescents from various cultural and ethnic groups, Barber (1994) found that conflicts occurred over day-to-day issues such as homework, money, curfews, clothing, chores, and friends. These types of arguments tend to decrease as teens develop (Galambos & Almeida, 1992). There is emerging research on the adolescent brain. Galvan, Hare, Voss, Glover and Casey (2007) examined its role in risk-taking behavior. They used fMRI to assess the readings’ relationship to risk-taking, risk perception, and impulsivity. The researchers found that there was no correlation between brain activity in the neural reward center and impulsivity and risk perception. However, activity in that part of the brain was correlated to risk taking. In other words, risk-taking adolescents experienced brain activity in the reward center. The idea that adolescents, however, are more impulsive than other demographics was challenged in their research, which included children and adults.
Emerging Adulthood
The next stage of development is emerging adulthood. This is a relatively newly defined period of lifespan development spanning from 18 years old to the mid-20s, characterized as an in-between time where identity exploration is focused on work and love.
When does a person become an adult? There are many ways to answer this question. In the United States, you are legally considered an adult at 18 years old. But other definitions of adulthood vary widely; in sociology, for example, a person may be considered an adult when she becomes self-supporting, chooses a career, gets married, or starts a family. The ages at which we achieve these milestones vary from person to person as well as from culture to culture. For example, in the African country of Malawi, 15-year-old Njemile was married at 14 years old and had her first child at 15 years old. In her culture she is considered an adult. Children in Malawi take on adult responsibilities such as marriage and work (e.g., carrying water, tending babies, and working fields) as early as 10 years old. In stark contrast, independence in Western cultures is taking longer and longer, effectively delaying the onset of adult life.
Why is it taking twenty-somethings so long to grow up? It seems that emerging adulthood is a product of both Western culture and our current times (Arnett, 2000). People in developed countries are living longer, allowing the freedom to take an extra decade to start a career and family. Changes in the workforce also play a role. For example, 50 years ago, a young adult with a high school diploma could immediately enter the work force and climb the corporate ladder. That is no longer the case. Bachelor’s and even graduate degrees are required more and more often—even for entry-level jobs (Arnett, 2000). In addition, many students are taking longer (five or six years) to complete a college degree as a result of working and going to school at the same time. After graduation, many young adults return to the family home because they have difficulty finding a job. Changing cultural expectations may be the most important reason for the delay in entering adult roles. Young people are spending more time exploring their options, so they are delaying marriage and work as they change majors and jobs multiple times, putting them on a much later timetable than their parents (Arnett, 2000).
Adulthood
Adulthood begins around 20 years old and has three distinct stages: early, middle, and late. Each stage brings its own set of rewards and challenges.
By the time we reach early adulthood (20 to early 40s), our physical maturation is complete, although our height and weight may increase slightly. In young adulthood, our physical abilities are at their peak, including muscle strength, reaction time, sensory abilities, and cardiac functioning. Most professional athletes are at the top of their game during this stage. Many women have children in the young adulthood years, so they may see additional weight gain and breast changes. Brain development is estimated to be complete at 25 years of age.
Middle adulthood extends from the 40s to the 60s (Figure 12.19). Physical decline is gradual. The skin loses some elasticity, and wrinkles are among the first signs of aging. Visual acuity decreases during this time. Women experience a gradual decline in fertility as they approach the onset of menopause, the end of the menstrual cycle, around 50 years old. Both men and women tend to gain weight: in the abdominal area for men and in the hips and thighs for women. Hair begins to thin and turn gray.
Late adulthood is considered to extend from the 60s on. This is the last stage of physical change. The skin continues to lose elasticity, reaction time slows further, and muscle strength diminishes. Smell, taste, hearing, and vision, so sharp in our twenties, decline significantly. The brain may also no longer function at optimal levels, leading to problems like memory loss, dementia, and Alzheimer’s disease in later years.
Because we spend so many years in adulthood (more than any other stage), cognitive changes are numerous. In fact, research suggests that adult cognitive development is a complex, ever changing process that may be even more active than cognitive development in infancy and early childhood (Fischer, Yan, & Stewart, 2003).
Unlike our physical abilities, which peak in our mid-20s and then begin a slow decline, our cognitive abilities remain steady throughout early and middle adulthood. Our crystallized intelligence (information, skills, and strategies we have gathered through a lifetime of experience) tends to hold steady as we age—it may even improve. For example, adults show relatively stable to increasing scores on intelligence tests until their mid-30s to mid-50s (Bayley & Oden, 1955). However, in late adulthood we begin to experience a decline in another area of our cognitive abilities—fluid intelligence (information processing abilities, reasoning, and memory). These processes become slower. How can we delay the onset of cognitive decline? Mental and physical activity seems to play a part (Figure 12.20). Research has found adults who engage in mentally and physically stimulating activities experience less cognitive decline and have a reduced incidence of mild cognitive impairment and dementia (Hertzog, Kramer, Wilson, & Lindenberger, 2009; Larson et al., 2006; Podewils et al., 2005).
Many elderly people experience dementia, changes in the brain that negatively affect cognition. Alzheimer’s disease is one type of dementia, initially studied by medical researcher Solomon Carter Fuller. Alzheimer’s disease has a genetic basis. Plaques in the brain are due to cell death, which then causes those affected with the disease severe forgetfulness. A person can forget how to walk, talk, and eventually eat. The disease can be mitigated by assessing environmental factors (exposure to lead, iron, and zinc increase risk) and nutritional factors (the Mediterranean diet lowers risk) (Arora, Mittal, & Kakkar, 2015). Although there is no cure, there is hope. Cognitive rehabilitation can offset mild cognitive impairment, as it can evolve into dementia. Garcia-Betances, Jimenez-Mixco, Arredondo, and Cabrera-Umpierrez (2015) examined the use of virtual reality as a possible cognitive rehabilitative method. They suggested that virtual reality technology should involve daily living activities, memory, and language, among other considerations.
There are many theories about the social and emotional aspects of aging. Some aspects of healthy aging include activities, social connectedness, and the role of a person’s culture. According to many theorists, including George Vaillant (2002), who studied and analyzed over 50 years of data, we need to have and continue to find meaning throughout our lives. For those in early and middle adulthood, meaning is found through work (Sterns & Huyck, 2001) and family life (Markus, Ryff, Curan, & Palmersheim, 2004). These areas relate to the tasks that Erikson referred to as generativity and intimacy. As mentioned previously, adults tend to define themselves by what they do—their careers. Earnings peak during this time, yet job satisfaction is more closely tied to work that involves contact with other people, is interesting, provides opportunities for advancement, and allows some independence (Mohr & Zoghi, 2006) than it is to salary (Iyengar, Wells, & Schwartz, 2006). How might being unemployed or being in a dead-end job challenge adult well-being?
Positive relationships with significant others in our adult years have been found to contribute to a state of well-being (Ryff & Singer, 2009). Most adults in the United States identify themselves through their relationships with family—particularly with spouses, children, and parents (Markus et al., 2004). While raising children can be stressful, especially when they are young, research suggests that parents reap the rewards down the road, as adult children tend to have a positive effect on parental well-being (Umberson, Pudrovska, & Reczek, 2010). Having a stable marriage has also been found to contribute to well-being throughout adulthood (Vaillant, 2002).
Another aspect of positive aging is believed to be social connectedness and social support. As we get older, socioemotional selectivity theory suggests that our social support and friendships dwindle in number, but remain as close, if not more close than in our earlier years (Carstensen, 1992) (Figure 12.21).
Stage Models of Development
By the end of this section, you will be able to:
- Describe the major tasks of psychosocial development according to Erikson
- Discuss Piaget’s view of cognitive development and apply the stages to understanding childhood cognition
- Describe Kohlberg’s theory of moral development
Erik Erikson’s Psychosocial Theory of Development
Erik Erikson (1902–1994) (Figure 12.22), took Freud’s psychosexual theory and modified it as psychosocial theory. While Freud focused on the id for driving development, Erikson focused on the ego as having a central role. Erikson’s psychosocial development theory emphasizes the social nature of our development rather than its sexual nature. While Freud believed that personality is shaped only in childhood, Erikson proposed that personality development takes place all through the lifespan, suggesting that how we interact with others within our culture is what affects our sense of self, or what he called the ego identity.
Erikson proposed that we are motivated by a need to achieve competence in certain areas of our lives. According to psychosocial theory, we experience eight stages of development over our lifespan, from infancy through late adulthood. At each stage there is a conflict, or task, that we need to resolve. Successful completion of each developmental task results in a sense of competence and a healthy personality. Failure to master these tasks leads to feelings of inadequacy and, similar to Freud’s idea of being fixated on a stage, can leave a person continue to struggle with that conflict.
According to Erikson (1963), trust is the basis of our development during infancy (birth to 12 months). Therefore, the primary tension of this stage is trust versus mistrust. Infants are dependent upon their caregivers, so caregivers who are responsive and sensitive to their infant’s needs help their baby to develop a sense of trust; their baby will see the world as a safe, predictable place. Unresponsive caregivers who do not meet their baby’s needs can engender feelings of anxiety, fear, and mistrust; their baby may see the world as unpredictable. The task is to find a balance, and the balance is shaped by culture. Erikson spent time with Sioux, a Native American tribe, and wrote about how breastfeeding reflect the generosity of the people; babies were never denied access to breastfeeding and allowed to wean themselves. Freud focused on the oral pleasure of breastfeed while Erikson saw the values of a culture being passed on in how breastfeeding and weaning were managed. A balance is sought in infancy between trusting too much and not enough that is line with their cultures and experiences.
As toddlers (ages 1–3 years) begin to explore their world, they learn that they can control their actions and act on the environment to get results. They begin to show clear preferences for certain elements of the environment, such as food, toys, and clothing. A toddler’s main task is to resolve the issue of autonomy versus shame and doubt, by working to establish independence. This is the “me do it” stage. For example, we might observe a budding sense of autonomy in a 2-year-old child who wants to choose her clothes and dress herself. Although her outfits might not be appropriate for the situation, her input in such basic decisions has an effect on her sense of independence. If denied the opportunity to act on her environment, she may begin to doubt her abilities, which could lead to low self-esteem and feelings of shame. Autonomy is often expressed with “no” as away to assert children’s sense of being different. When children are not permitted by parent to assert some autonomy, they may be overwhelmed by feelings of shame and doubt. While Freud focused on potty training, Erikson also would consider the child’s sense of autonomy in successfully learning to use the toilet and the shame and doubt stirred by parents who condemned accidents to be an important part of how the conflict is resolved.
Once children reach the preschool stage (ages 3–6 years), they are capable of initiating activities and asserting control over their world through social interactions and play. According to Erikson, preschool children must resolve the task of initiative versus guilt. Children tend to be more social during stage, and the conflict is about who they are in relation to the people around them. By learning to plan and achieve goals while interacting with others, preschool children can develop initiative. Those who do will develop self-confidence and feel a sense of purpose. Those who tend to be unsuccessful at this stage—with their initiative misfiring or stifled—may develop feelings of guilt. Parents who do not allow children to take some initiative may struggle with ever feeling they can. It should be noted that the guilt a child feels in response to problems in this stage is about the struggle to “make it right” with other people while the shame and doubt of the previous stage is about the child’s sense of self.
During the elementary school stage (ages 7–11), Freud argued children had a quiet period without much sexual energy driving relationship, but for Erikson, children face the task of industry versus inferiority. Children begin to compare themselves to their peers to see how they measure up. They either develop a sense of pride and accomplishment in their schoolwork, sports, social activities, and family life, or they feel inferior and inadequate when they don’t measure up. What are some things parents and teachers can do to help children develop a sense of competence and a belief in themselves and their abilities?
In adolescence (ages 12–18), youth face the task of identity versus role confusion or diffusion. Freud focused on the adolescent directing libido to a socially acceptable target. According to Erikson, an adolescent’s main task is developing a sense of identity. Adolescents struggle with questions such as “Who am I?” and “What do I want to do with my life?” Along the way, most adolescents try on many different selves to see which ones fit. Adolescents who are successful at this stage have a strong sense of identity and are able to remain true to their beliefs and values in the face of problems and other people’s perspectives. What happens to apathetic adolescents, who do not make a conscious search for identity, or those who are pressured to conform to their parents’ ideas for the future? These teens will have a weak sense of identity and experience role confusion. They are unsure of their identity and confused about the future, lacking commitment. Some adolescents adopt the values and roles that their parents expect for them. Other teens develop identities that are in opposition to their parents but align with a peer group. This is common as peer relationships become a central focus in adolescents’ lives.
As adolescents work to form their identities, they pull away from their parents, and the peer group becomes very important (Shanahan, McHale, Osgood, & Crouter, 2007). Despite spending less time with their parents, most teens report positive feelings toward them (Moore, Guzman, Hair, Lippman, & Garrett, 2004). Warm and healthy parent-child relationships have been associated with positive child outcomes, such as better grades and fewer school behavior problems, in the United States as well as in other countries (Hair et al., 2005).
People in early adulthood (i.e., 20s through early 40s) are concerned with intimacy versus isolation. After we have developed a sense of identity in adolescence, we are ready to share our life with others. Erikson said that we must have a strong sense of identity before developing intimate relationships with others. By contrast, Harry Stack Sullivan (Rychlak, 1981, p. 351) argued that an ability to be intimate was needed before identity could truly form. Erikson focused on the problem of early adulthood as one of creating one’s own family with satisfying intimacy or facing potential isolation throughout one’s remaining days.
When people reach their 40s, they enter the time known as middle adulthood, which extends to the mid-60s. The social task of middle adulthood is generativity versus stagnation. Generativity involves finding your life’s work and contributing to the development of others, through activities such as volunteering, mentoring, and raising children. Initially, Erikson focused solely on having children as the way to develop productivity but later saw that art and scholarship and other aspects of work could also provide a sense of contributing the next generations. Those who do not find some generative fulfillment may experience stagnation, having little connection with others and little interest in productivity and self-improvement. The reality is that, as with all stages, some feelings of stagnation are inevitable.
From the mid-60s to the end of life, we are in the period of development known as late adulthood. Erikson’s task at this stage is called integrity versus despair. He said that people in late adulthood reflect on their lives and feel either a sense of satisfaction or a sense of failure. People who feel proud of their accomplishments feel a sense of integrity, and they can look back on their lives with few regrets. However, people who are not successful at this stage may feel as if their life has been wasted. They focus on what “would have,” “should have,” and “could have” been. They face the end of their lives with feelings of bitterness, depression, and despair. Table 12.3 summarizes the stages of Erikson’s theory.
| Table 12.3: Erikson’s Psychosocial Stages of Development | |||
|---|---|---|---|
| Stage | Age (years) | Developmental Task | Description |
| 1 | 0–1 | Trust vs. mistrust | Trust (or mistrust) that basic needs, such as nourishment and affection, will be met |
| 2 | 1–3 | Autonomy vs. shame/doubt | Develop a sense of independence in many tasks |
| 3 | 3–6 | Initiative vs. guilt | Take initiative on some activities—may develop guilt when unsuccessful or boundaries overstepped |
| 4 | 7–11 | Industry vs. inferiority | Develop self-confidence in abilities when competent or sense of inferiority when not |
| 5 | 12–18 | Identity vs. confusion | Experiment with and develop identity and roles |
| 6 | 19–29 | Intimacy vs. isolation | Establish intimacy and relationships with others |
| 7 | 30–64 | Generativity vs. stagnation | Contribute to society and be part of a family |
| 8 | 65– | Integrity vs. despair | Assess and make sense of life and meaning of contributions |
Piaget’s Cognitive Theory of Development
Jean Piaget (1896–1980) is another stage theorist who studied childhood development (Figure 12.23). Instead of approaching development from a psychoanalytical or psychosocial perspective, Piaget focused on children’s cognitive growth, seeking to explain the development of rational thought. He believed that thinking is a central aspect of development and that children are naturally inquisitive. However, he said that children do not think and reason like adults (Piaget, 1930, 1932). His theory of cognitive development holds that our cognitive abilities develop through specific stages, which exemplifies the discontinuity approach to development. As we progress to a new stage, there is a distinct shift in how we think and reason.
For example, 2-year-old Abdul learned the schema for dogs because his family has a Labrador retriever. When Abdul sees other dogs in his picture books, he says, “Look mommy, dog!” Thus, he has assimilated them into his schema for dogs. One day, Abdul sees a sheep for the first time and says, “Look mommy, dog!” Having a basic schema that a dog is an animal with four legs and fur, Abdul thinks all furry, four-legged creatures are dogs. When Abdul’s mom tells him that the animal he sees is a sheep, not a dog, Abdul must accommodate his schema for dogs to include more information based on his new experiences. Abdul’s schema for dog was too broad, since not all furry, four-legged creatures are dogs. He now modifies his schema for dogs and forms a new one for sheep.
Like Freud and Erikson, Piaget thought development unfolds in a series of stages approximately associated with age ranges. He proposed a theory of cognitive development that unfolds in four stages: sensorimotor, preoperational, concrete operational, and formal operational (Table 12.4).
| Table 12.4: Piaget’s Stages of Cognitive Development | |||
|---|---|---|---|
| Age (years) | Stage | Description | Developmental issues |
| 0–2 | Sensorimotor | World experienced through senses and actions | Object permanence Stranger anxiety |
| 2–6 | Preoperational | Use words and images to represent things, but lack logical reasoning | Pretend play Egocentrism Language development |
| 7–11 | Concrete operational | Understand concrete events and analogies logically; perform arithmetical operations | Conservation Mathematical transformations |
| 12– | Formal operational | Formal operations Utilize abstract reasoning |
Abstract logic Moral reasoning |
In Piaget’s view, around the same time children develop object permanence (around 8 months old), they also begin to exhibit stranger anxiety, which is a fear of unfamiliar people. Babies may demonstrate this by crying and turning away from a stranger, by clinging to a caregiver, or by attempting to reach their arms toward familiar faces such as parents. Stranger anxiety results when a child is unable to assimilate the stranger into an existing schema; therefore, she can’t predict what her experience with that stranger will be like, which results in a fear response. Children also may exhibit separation anxiety, crying when their caregivers leave because now they understand that their caregiver still exists when they cannot see them.
Piaget’s second stage is the preoperational stage, which is from approximately 2 to 7 years old. In this stage, children can use symbols to represent words, images, and ideas, which is why children in this stage engage in pretend play. A child’s arms might become airplane wings as he zooms around the room, or a child with a stick might become a brave knight with a sword. Children also begin to use language in the preoperational stage, but they cannot understand adult logic or mentally manipulate information (the term operational refers to logical manipulation of information, so children at this stage are considered to be pre-operational). Children’s logic is based on their own personal knowledge of the world so far, rather than on conventional knowledge. For example, dad gave a slice of pizza to 10-year-old Keiko and another slice to her 3-year-old brother, Kenny. Kenny’s pizza slice was cut into five pieces, so Kenny told his sister that he got more pizza than she did. Children in this stage has a sense of number, but they cannot reconcile both their understanding of number and mass. They cannot perform logical operations because they have not developed an understanding of conservation, which is the idea that even if you change the appearance of something, it has not changed in other ways as long as nothing has been removed or added. Piaget developed a range of conservation tasks to explore how children made sense of different kinds of change.
During this stage, we also expect children to display egocentrism, which means that the child is not able to take the perspective of others. A child at this stage thinks that everyone sees, thinks, and feels just as they do. Let’s look at Kenny and Keiko again. Keiko’s birthday is coming up, so their mom takes Kenny to the toy store to choose a present for his sister. He selects an Iron Man action figure for her, thinking that if he likes the toy, his sister will too. An egocentric child is not able to infer the perspective of other people and instead attributes his own perspective.
Piaget’s third stage is the concrete operational stage, which occurs from about 7 to 11 years old. In this stage, children can think logically about real (concrete) events; they have a firm grasp on the use of numbers and start to employ memory strategies. They can perform mathematical operations and understand transformations, such as addition is the opposite of subtraction, and multiplication is the opposite of division. In this stage, children also master the concept of conservation: Even if something changes shape, its mass, volume, and number stay the same. For example, if you pour water from a tall, thin glass to a short, fat glass, you still have the same amount of water. Remember Keiko and Kenny and the pizza? How did Keiko know that Kenny was wrong when he said that he had more pizza?
Children in the concrete operational stage also understand the principle of reversibility, which means that objects can be changed and then returned back to their original form or condition. Take, for example, water that you poured into the short, fat glass: You can pour water from the fat glass back to the thin glass and still have the same amount (minus a couple of drops).
The fourth, and last, stage in Piaget’s theory is the formal operational stage, which is from about age 11 to adulthood. Whereas children in the concrete operational stage are able to think logically only about concrete events, children in the formal operational stage can also deal with abstract ideas and hypothetical situations. Children in this stage can use abstract thinking to problem solve, look at alternative solutions, and test these solutions. In adolescence, a renewed egocentrism occurs. For example, a 15-year-old with a very small pimple on her face might think it is huge and incredibly visible, under the mistaken impression that others must share her perceptions.
According to Piaget, the highest level of cognitive development is formal operational thought, which develops between 11 and 20 years old. However, many developmental psychologists disagree with Piaget, suggesting a fifth stage of cognitive development, known as the postformal stage (Basseches, 1984; Commons & Bresette, 2006; Sinnott, 1998). In postformal thinking, decisions are made based on situations and circumstances, and logic is integrated with emotion as adults develop principles that depend on contexts. One way that we can see the difference between an adult in postformal thought and an adolescent in formal operations is in terms of how they handle emotionally charged issues.
It seems that once we reach adulthood our problem solving abilities change: As we attempt to solve problems, we tend to think more deeply about many areas of our lives, such as relationships, work, and politics (Labouvie-Vief & Diehl, 1999). Because of this, postformal thinkers are able to draw on past experiences to help them solve new problems. Problem-solving strategies using postformal thought vary, depending on the situation. What does this mean? Adults can recognize, for example, that what seems to be an ideal solution to a problem at work involving a disagreement with a colleague may not be the best solution to a disagreement with a significant other.
Moral Theory Of Development
A major task beginning in childhood and continuing into adolescence is discerning right from wrong. Psychologist Lawrence Kohlberg (1927–1987) extended upon the foundation that Piaget built regarding cognitive development. Kohlberg believed that moral development, like cognitive development, follows a series of stages. To develop this theory, Kohlberg posed moral dilemmas to people of all ages, and then he analyzed their answers to find evidence of their particular stage of moral development. Before reading about the stages, take a minute to consider how you would answer one of Kohlberg’s best-known moral dilemmas, commonly known as the Heinz dilemma:
In Europe, a woman was near death from a special kind of cancer. There was one drug that the doctors thought might save her. It was a form of radium that a druggist in the same town had recently discovered. The drug was expensive to make, but the druggist was charging ten times what the drug cost him to make. He paid $200 for the radium and charged $2,000 for a small dose of the drug. The sick woman’s husband, Heinz, went to everyone he knew to borrow the money, but he could only get together about $1,000, which is half of what it cost. He told the druggist that his wife was dying and asked him to sell it cheaper or let him pay later. But the druggist said: “No, I discovered the drug and I’m going to make money from it.” So Heinz got desperate and broke into the man’s store to steal the drug for his wife. Should the husband have done that? (Kohlberg, 1969, p. 379)
How would you answer this dilemma? Kohlberg was not interested in whether you answer yes or no to the dilemma: Instead, he was interested in the reasoning behind your answer.
After presenting people with this and various other moral dilemmas, Kohlberg reviewed people’s responses and placed them in different stages of moral reasoning (Figure 12.24). According to Kohlberg, an individual progresses from the capacity for pre-conventional morality (before age 9) to the capacity for conventional morality (early adolescence), and toward attaining post-conventional morality (once formal operational thought is attained), which only a few fully achieve. Kohlberg placed in the highest stage responses that reflected the reasoning that Heinz should steal the drug because his wife’s life is more important than the pharmacist making money. The value of a human life overrides the pharmacist’s greed.
How does this theory apply to males and females? Kohlberg (1969) felt that more males than females move past stage four in their moral development. He went on to note that women seem to be deficient in their moral reasoning abilities. These ideas were not well received by Carol Gilligan, a research assistant of Kohlberg, who consequently developed her own ideas of moral development. In her groundbreaking book, In a Different Voice: Psychological Theory and Women’s Development, Gilligan (1982) criticized her former mentor’s theory because it was based only on upper class White men and boys. She argued that women are not deficient in their moral reasoning—she proposed that males and females reason differently. Kohlberg’s theory emphasizes the rule of law and a rational approach to resolving dilemmas, which represents a typically male approach, but girls and women focus more on staying connected and the importance of interpersonal relationships. Therefore, in the Heinz dilemma, many girls and women respond that Heinz should not steal the medicine. Their reasoning is that if he steals the medicine, is arrested, and is put in jail, then he and his wife will be separated, and she could die while he is still in prison.
CONNECT THE CONCEPTS: Neuroconstructivism
The genetic environmental correlation you’ve learned about concerning the bidirectional influence of genes and the environment has been explored in more recent theories (Newcombe, 2011). One such theory, neuroconstructivism, suggests that neural brain development influences cognitive development. Experiences that a child encounters can impact or change the way that neural pathways develop in response to the environment. An individual’s behavior is based on how one understands the world. There is interaction between neural and cognitive networks at and between each level, consisting of these:
- genes
- neurons
- brain
- body
- social environment
These interactions shape mental representations in the brain and are dependent on context that individuals actively explore throughout their lifetimes (Westermann, Mareschal, Johnson, Sirois, Spratling, & Thomas, 2007).
An example of this would be a child who may be genetically predisposed to a difficult temperament. They may have parents who provide a social environment in which they are encouraged to express themselves in an optimal manner. The child’s brain would form neural connections enhanced by that environment, thus influencing the brain. The brain gives information to the body about how it will experience the environment. Thus, neural and cognitive networks work together to influence genes (i.e., attenuating temperament), body (i.e., may be less prone to high blood pressure), and social environment (i.e., may seek people who are similar to them).
Models of Continuous Development
By the end of this section, you will be able to:
- Explain how information processing theorists have reorganized Piaget’s theory as a model with continuous development
- Understand different ways sociocultural contexts can shape development
- Compare and contrast the strengths and weaknesses of major developmental theories
Stage theories have been an important part of developmental psychology, but multiple theories argue that development does not happen in relatively sudden, universal shifts but are more gradual or context-dependent. Stage theories predict shifts between qualitatively different stages: Freud’s stages were shaped by the orifice or body part that he believed was central, and once a child moved from one stage to another, there was no going back (though the idea of fixation explained how someone could be stuck in a stage). Erikson’s theory focused a different conflict to resolve for each stage, and Piaget argued for leaps in the ability to be rational as children grew. By contrast, theories with a continuous model of development focus on the little changes that accumulate in bigger changes.
Several of Piaget’s ideas about stages have come under criticism by researchers taking an information processing perspective. Several contemporary studies support a model of development that is more continuous, showing that children can perform simplified versions of the tasks Piaget developed younger than his research had found (Courage & Howe, 2002; Siegler, 2005, 2006; Baillargeon, 2004; de Hevia & Spelke, 2010). Piaget thought that children’s ability to understand objects—such as learning that a rattle makes a noise when shaken—was a cognitive skill that develops slowly as a child matures and interacts with the environment. Researchers have found, however, that even very young children understand objects and how they work long before they have experience with those objects (Baillargeon, 1987; Baillargeon, Li, Gertner, & Wu, 2011). For example, children as young as 3 months old demonstrated knowledge of the properties of objects that they had only viewed and did not have prior experience with them. In one study, 3-month-old infants were shown a truck rolling down a track and behind a screen. The box, which appeared solid but was actually hollow, was placed next to the track. The truck rolled past the box as would be expected. Then the box was placed on the track to block the path of the truck. When the truck was rolled down the track this time, it continued unimpeded. The infants spent significantly more time looking at this impossible event (Figure 12.25). Baillargeon (1987) concluded that they knew solid objects cannot pass through each other. Baillargeon’s findings suggest that very young children have an understanding of objects and how they work, which Piaget (1954) would have said is beyond their cognitive abilities due to their limited experiences in the world. Piaget argued, however, that the task is significantly different, not requiring the level of organization necessary to look for a toy under a blanket, and therefore was not evidence of an organized understanding of object permanence but was capturing early sign of what was developing.
Similarly in middle and late childhood (6–11 years old), information processing theorists argue that thought processes become gradually more logical and organized when dealing with concrete information (Figure 12.26). Children at this age begin to understand concepts such as the past, present, and future, giving them the ability to plan and work toward goals. Additionally, they can process complex ideas such as addition and subtraction and cause-and-effect relationships. However, children’s attention spans tend to be very limited until they are around 11 years old. After that point, it begins to improve through adulthood. In these ways, information processing acknowledged the milestones Piaget observed, but through a process of simplifying the tasks, demonstrated that there is gradual change. The question is about whether these simplified tasks show that development is continuous or show that small changes lead to a reorganization in thinking that is stage-like.
EVERYDAY CONNECTION: The Importance of Play and Recess
According to the American Academy of Pediatrics (2007), unstructured play is an integral part of a child’s development. It builds creativity, problem solving skills, and social relationships. Play also allows children to develop a theory-of-mind as they imaginatively take on the perspective of others.
Outdoor play allows children the opportunity to directly experience and sense the world around them. While doing so, they may collect objects that they come across and develop lifelong interests and hobbies. They also benefit from increased exercise, and engaging in outdoor play can actually increase how much they enjoy physical activity. This helps support the development of a healthy heart and brain. Unfortunately, research suggests that today’s children are engaging in less and less outdoor play (Clements, 2004). Perhaps, it is no surprise to learn that lowered levels of physical activity in conjunction with easy access to calorie-dense foods with little nutritional value are contributing to alarming levels of childhood obesity (Karnik & Kanekar, 2012).
Despite the adverse consequences associated with reduced play, some children are over scheduled and have little free time to engage in unstructured play. In addition, some schools have taken away recess time for children in a push for students to do better on standardized tests, and many schools commonly use loss of recess as a form of punishment. Do you agree with these practices? Why or why not?
Sociocultural Theories of Development
Many different theorists have put the emphasis on sociocultural contexts to understand psychological development, and Lev Vygotsky (1896-1934) was a Russian psychologist who is associated with the beginnings of this approach. He suggested that human development is rooted in one’s culture. A child’s social world, for example, forms the basis for the formation of language and thought. The language one speaks and the ways a person thinks about things is dependent on one’s cultural background. Vygotsky also considered historical influences as key to one’s development. He was interested in the process of development and the individual’s interactions with their environment (John-Steiner & Mahn, 1996).
Vygotsky rooted his work in that of Karl Marx, arguing that, just as tools have been developed that transformed society from small communities dependent on hunting and gathering to complex societies, so humans develop with the tools we inherit from our families and communities (Vygotsky & Luria, 1930/1994). The most important tool is that of language, which changes us. While Pavlov had theorized about the association in stimulus-response learning, Vygotsky argued that humans have language to mediate this relationship (Vygotsky, 1934/1962). We do not simply respond to the environment, but in the use of language and other signs, we can step back and think about how to respond.
This emphasis on language as a tool led to a clear conflict with the work of Piaget. Piaget viewed early childhood as being characterized by egocentric speech, but Vygotsky argued that this was private speech in the process of becoming internalized (Vygotsky, 1934/1962). Vygotsky argued that everything psychological began as social: Our first words were about communicating with those around us. Language begins on the social or interpersonal plane, but as we master it, we internalize it and use it intrapersonally or psychologically to shape our behavior (Vygotsky, 2004).
Language then guides our attention, helps us to develop self-control, frees us from the immediate context to plan different actions, and allows us to become fully conscious with the ability to self-reflect.
The most well-known concept to come from Vygotsky and to influence the field of education is the zone of proximal development. This is defined as the difference between what a person is able to do on their own and is possible with someone’s support (Vygotsky, 2004). This zone reflects the potential for development. If children or adults need no help to complete a task, then they do not need to develop, and if they cannot do it even with support, they are not ready. An example is when a child sees a puzzle for the first time. If the child can respond to prompts such as, “look for the pieces with flowers and see if they can fit together,” then the puzzle is within their zone of proximal development. Teachers have found this useful as a model for who they can help students to develop in assignments. Professors may break down an assignment into stages or directions that specifically guide a student in how to approach the assignment as a way to scaffold their progress.
Many approaches have developed in response to Vygotsky’s work. One theory is Bronfenbrenner’s ecological systems theory (Figure 12.27) that models different layers of cultural influence in development. In addition to explaining development, sociocultural work has focused on supporting neurodiverse individuals.
DIG DEEPER: Phenomenological Variant of Ecological Systems Theory (PVEST)
Kenneth and Mamie Clark were pioneering psychologists responsible for the first psychological study used in a Supreme Court case. Their research with African American children and doll choices was used to highlight the harmful effects of segregation and provided support for the Browns and the NAACP in their lawsuit against the Board of Education. The finding that African American children were more likely to choose a white doll over a black doll, in both northern and southern states, led them to theorize that the children did not have a healthy concept of themselves (Clark & Clark, 1950).
The Clarks’ research differed from that of Inez Beverly Prosser, who also studied African American children in segregated and integrated schools in Cincinnati. Parents could choose either environment for their children during the 1930s. She found, among other factors, that the self-concept of children at segregated schools was more positive versus those in integrated schools, partly due to teachers’ low expectations. Prosser also noted that the child’s personality should be considered when choosing a segregated school or an integrated school (Benjamin, Henry, & McMahon, 2005).
Later researchers suggested that African American children choosing a doll that did not look like them was not an indication of their self-esteem or their self-image. For instance, Rogers and Meltzoff (2017) found that gender identity was more important than race in their study of diverse children whose average age was about 10 years old. Thus, for children that young, the meaning of race is an evolving process, as opposed to adolescents’ search for identity. The ethnic minority children in the study did view racial identity as important, compared to their white counterparts.
For teenagers who are members of ethnic minority groups, racial/ethnic/cultural identity can be paramount, depending on the family’s processes. Racial socialization involves teaching them the positive aspects of their in-group, usually by caregivers. Most of the students in a study by Neblett, Smalls, Ford, Nguyen, and Sellers (2009) reported having received such messages but a few received no racial socialization messages. They found that these messages played a role in how they felt about their in-group.
Some theories have been developed to explain the behaviors of ethnic minority youth. One such theory is the Phenomenological Variant of Ecological Systems Theory (PVEST), put forth by Margaret Beale Spencer. It is a merging of phenomenology and Bronfenbrenner’s ecological systems theory. A phenomenological approach is based on how a person makes meaning of their experiences. For example, young African American boys have different experiences in educational settings compared to African American girls. Consequently, the meaning they assign to those experiences differs. Bronfenbrenner’s ecological systems theory suggests that development occurs based on interactions among environments such as school, family, and community (Bronfenbrenner, 1977).
The research that Spencer, Dupree, and Hartmann (1997) conducted with African American adolescent boys and girls was explained by PVEST. They found that negative learning attitudes were predicted by unpopularity with peers for girls and boys. Additionally, for boys, more stress predicted a less negative attitude toward learning, possibly due to focus on the school environment instead of on personal issues. This occurred along with perceiving that teachers had positive expectations of African American boys. The researchers surmised that PVEST accounted for how others’ perceptions and their subsequent attitudes were related and worked both ways.
Key Terms
- accommodation
- adjustment of a schema by changing a scheme to accommodate new information different from what was already known
- adolescence
- period of development that begins at puberty and ends at early adulthood
- adrenarche
- maturing of the adrenal glands
- advance directive
- a written legal document that details specific interventions a person wants (see living will)
- allele
- specific version of a gene
assimilation
adjustment of a schema by adding information similar to what is already known
- attachment
- long-standing connection or bond with others
- authoritarian parenting style
- parents place a high value on conformity and obedience, are often rigid, and express little warmth to the child
- authoritative parenting style
- parents give children reasonable demands and consistent limits, express warmth and affection, and listen to the child’s point of view
- avoidant attachment
- characterized by child’s unresponsiveness to parent, does not use the parent as a secure base, and does not care if parent leaves
- chromosome
- long strand of genetic information
cognitive development
domain of lifespan development that examines learning, attention, memory, language, thinking, reasoning, and creativity
- cognitive empathy
- ability to take the perspective of others and to feel concern for others
- conception
- when a sperm fertilizes an egg and forms a zygote
- concrete operational stage
- third stage in Piaget’s theory of cognitive development; from about 7 to 11 years old, children can think logically about real (concrete) events
- conservation
- idea that even if you change the appearance of something, it is still equal in size, volume, or number as long as nothing is added or removed
- continuous development
- view that development is a cumulative process: gradually improving on existing skills
- critical (sensitive) period
- time during fetal growth when specific parts or organs develop
- developmental milestone
- approximate ages at which children reach specific normative events
- discontinuous development
- view that development takes place in unique stages, which happen at specific times or ages
- disorganized attachment
- characterized by the child’s odd behavior when faced with the parent; type of attachment seen most often with kids that are abused
- do not resuscitate (DNR)
- a legal document stating that if a person stops breathing or their heart stops, medical personnel such as doctors and nurses are not to take steps to revive or resuscitate the patient
- dominant allele
- allele whose phenotype will be expressed in an individual that possesses that allele
egocentrism
preoperational child’s difficulty in taking the perspective of others
- embryo
- multi-cellular organism in its early stages of development
- emerging adulthood
- newly defined period of lifespan development from 18 years old to the mid-20s; young people are taking longer to complete college, get a job, get married, and start a family
- epigenetics
- study of gene-environment interactions, such as how the same genotype leads to different phenotypes
fine motor skills
use of muscles in fingers, toes, and eyes to coordinate small actions
- formal operational stage
- final stage in Piaget’s theory of cognitive development; from age 11 and up, children are able to deal with abstract ideas and hypothetical situations
- fraternal twins
- twins who develop from two different eggs fertilized by different sperm, so their genetic material varies the same as in non-twin siblings
- gene
- sequence of DNA that controls or partially controls physical characteristics
- genetic environmental correlation
- view of gene-environment interaction that asserts our genes affect our environment, and our environment influences the expression of our genes
- genotype
- genetic makeup of an individual
gonadarche
maturing of the sex glands
- gross motor skills
- use of large muscle groups to control arms and legs for large body movements
- health care proxy
- a legal document that appoints a specific person to make medical decisions for a patient if they are unable to speak for themselves
- hospice
- service that provides a death with dignity; pain management in a humane and comfortable environment; usually outside of a hospital setting
- identical twins
- twins that develop from the same sperm and egg
living will
a written legal document that details specific interventions a person wants; may include health care proxy
- menarche
- beginning of menstrual period; around 12–13 years old
- mitosis
- process of cell division
- motor skills
- ability to move our body and manipulate objects
- mutation
- sudden, permanent change in a gene
nature
genes and biology
- newborn reflexes
- inborn automatic response to a particular form of stimulation that all healthy babies are born with
- normative approach
- study of development using norms, or average ages, when most children reach specific developmental milestones
- nurture
- environment and culture
- object permanence
- idea that even if something is out of sight, it still exists
- permissive parenting style
- parents make few demands and rarely use punishment
- phenotype
- individual’s inheritable physical characteristics
physical development
domain of lifespan development that examines growth and changes in the body and brain, the senses, motor skills, and health and wellness
- placenta
- structure connected to the uterus that provides nourishment and oxygen to the developing baby
- prenatal care
- medical care during pregnancy that monitors the health of both the mother and the fetus
- preoperational stage
- second stage in Piaget’s theory of cognitive development; from ages 2 to 7, children learn to use symbols and language but do not understand mental operations and often think illogically
- primary sexual characteristics
- organs specifically needed for reproduction
- psychosexual development
- process proposed by Freud in which pleasure-seeking urges focus on different erogenous zones of the body as humans move through five stages of life
- psychosocial development
- domain of lifespan development that examines emotions, personality, and social relationships
- psychosocial development
- process proposed by Erikson in which social tasks are mastered as humans move through eight stages of life from infancy to adulthood
- recessive allele
- allele whose phenotype will be expressed only if an individual is homozygous for that allele
resistant attachment
characterized by the child’s tendency to show clingy behavior and rejection of the parent when they attempt to interact with the child
- reversibility
- principle that objects can be changed, but then returned back to their original form or condition
- schema
- (plural = schemata) concept (mental model) that is used to help us categorize and interpret information
- secondary sexual characteristics
- physical signs of sexual maturation that do not directly involve sex organs
- secure attachment
- characterized by the child using the parent as a secure base from which to explore
- secure base
- parental presence that gives the infant/toddler a sense of safety as they explore their surroundings
- sensorimotor stage
- first stage in Piaget’s theory of cognitive development; from birth through age 2, a child learns about the world through senses and motor behavior
- socioemotional selectivity theory
- social support/friendships dwindle in number, but remain as close, if not more close than in earlier years
- spermarche
- first male ejaculation
- stage of moral reasoning
- process proposed by Kohlberg; humans move through three stages of moral development
- temperament
- innate traits that influence how one thinks, behaves, and reacts with the environment
- teratogen
- biological, chemical, or physical environmental agent that causes damage to the developing embryo or fetus
- theory of evolution by natural selection
- states that organisms that are better suited for their environments will survive and reproduce compared to those that are poorly suited for their environments
uninvolved parenting style
parents are indifferent, uninvolved, and sometimes referred to as neglectful; they don’t respond to the child’s needs and make relatively few demands
- zygote
- structure created when a sperm and egg merge at conception; begins as a single cell and rapidly divides to form the embryo and placenta
Summary
Human Genetics
Genes are sequences of DNA that code for a particular trait. Different versions of a gene are called alleles—sometimes alleles can be classified as dominant or recessive. A dominant allele always results in the dominant phenotype. In order to exhibit a recessive phenotype, an individual must be homozygous for the recessive allele. Genes affect both physical and psychological characteristics. Ultimately, how and when a gene is expressed, and what the outcome will be—in terms of both physical and psychological characteristics—is a function of the interaction between our genes and our environments.
9.1 What Is Lifespan Development?
Lifespan development explores how we change and grow from conception to death. This field of psychology is studied by developmental psychologists. They view development as a lifelong process that can be studied scientifically across three developmental domains: physical, cognitive development, and psychosocial. There are several theories of development that focus on the following issues: whether development is continuous or discontinuous, whether development follows one course or many, and the relative influence of nature versus nurture on development.
9.2 Lifespan Theories
There are many theories regarding how babies and children grow and develop into happy, healthy adults. Sigmund Freud suggested that we pass through a series of psychosexual stages in which our energy is focused on certain erogenous zones on the body. Eric Erikson modified Freud’s ideas and suggested a theory of psychosocial development. Erikson said that our social interactions and successful completion of social tasks shape our sense of self. Jean Piaget proposed a theory of cognitive development that explains how children think and reason as they move through various stages. Finally, Lawrence Kohlberg turned his attention to moral development. He said that we pass through three levels of moral thinking that build on our cognitive development.
9.3 Stages of Development
At conception the egg and sperm cell are united to form a zygote, which will begin to divide rapidly. This marks the beginning of the first stage of prenatal development (germinal stage), which lasts about two weeks. Then the zygote implants itself into the lining of the uterus, marking the beginning of the second stage of prenatal development (embryonic stage), which lasts about six weeks. The embryo begins to develop body and organ structures, and the neural tube forms, which will later become the brain and spinal cord. The third phase of prenatal development (fetal stage) begins at 9 weeks and lasts until birth. The body, brain, and organs grow rapidly during this stage. During all stages of pregnancy it is important that the parent receive prenatal care to reduce health risks to themself and to the developing baby.
Newborn infants weigh about 7.5 pounds. Doctors assess a newborn’s reflexes, such as the sucking, rooting, and Moro reflexes. Our physical, cognitive, and psychosocial skills grow and change as we move through developmental stages from infancy through late adulthood. Attachment in infancy is a critical component of healthy development. Parenting styles have been found to have an effect on childhood outcomes of well-being. The transition from adolescence to adulthood can be challenging due to the timing of puberty, and due to the extended amount of time spent in emerging adulthood. Although physical decline begins in middle adulthood, cognitive decline does not begin until later. Activities that keep the body and mind active can help maintain good physical and cognitive health as we age. Social supports through family and friends remain important as we age.
9.4 Death and Dying
Death marks the endpoint of our lifespan. There are many ways that we might react when facing death. Kübler-Ross developed a five-stage model of grief as a way to explain this process. Many people facing death choose hospice care, which allows their last days to be spent at home in a comfortable, supportive environment.
