chpt one

Plasticity is especially useful when anticipating growth of a particular person: Everyone is constrained by past circumstances, but no one is confined by them. Plasticity emphasizes that people can and do change, that predictions are not always accurate. Three insights already explained have improved predictions:

1.Nature and nurture always interact. 2.Certain ages are sensitive periods for particular kinds of development. 3. Genes predispose people to respond to certain circumstances, in differential susceptibility.

hypothesis

A specific prediction that can be tested, and proven or disproved.

The term plasticity denotes two complementary aspects of development:

Human traits can be molded (as plastic can be), yet people maintain a certain durability (as plastic does). This provides both hope and realism—hope because change is possible and realism because development builds on what has come before. The idea that abilities, personality, and other human characteristics are moldable, and thus can change. Plasticity is basic to our life-span perspective because it simultaneously incorporates two facts: 1.People can change over time. 2. New behavior depends partly on what has already happened. The most surprising example of plasticity in recent years involves the brain. Expansion of neurological structures, networks of communication between one cell and another, and even creation of neurons (brain cells) occurs in adulthood.

a leading developmentalist, Urie Bronfenbrenner (1917-2005), recognized that context is crucial.

Just as a naturalist studying an organism examines the ecology (the multifaceted relationship between the organism and its environment), Bronfenbrenner recommended that developmentalists take an ecological-systems approach

Remember that difference is not always

deficit.

Bronfenbrenner

studied people in natural settings. He wanted to learn how people interact with each other at home, at school, or at work, and he did not want to study people in a scientist's laboratory or by having them answer questionnaires about their behavior. He watched them doing things in real life, not writing about what they did. renamed his approach bioecological to highlight the role of biology. He recognized that systems within the body (e.g., the sexual-reproductive system, the cardiovascular system) affect the external contexts

Multi-Directional

If human traits were all charted over time from birth to death, some traits would appear, others disappear, with increases, decreases, and zigzags The traditional idea—that all development advances until about age 18, steadies, and then declines—has been refuted by life-span research. pace of change varies: discontinuity is evident: Change can occur rapidly and dramatically, continuity is found: Growth can be gradual, Even stability is possible. Some characteristics seem not to change. Although linear progress seems most common, scientists now find that almost no aspect of human change follows the linear pattern exactly. There is simple growth, radical transformation, improvement, and decline in almost every aspect of development. There is also stability and continuity—day to day, year to year, and generation to generation. Life-span theorists see gains and losses throughout life, often at the same time

Development Is

Multi-Directional

ethnic group

People whose ancestors were born in the same region. Usually they share a language, culture, and/or religion. primarily social constructions, dependent on context. People of an ethnic group share certain attributes, almost always including ancestral heritage and usually national origin, religion, and language. This means that ethnic groups often—but not always—share a culture. Some people share ethnicity but not culture (consider people of Irish descent in Ireland, Australia, and North America), and some cultures include people of several ethnic groups (consider British culture).

Replication—

Repeating a study, usually using different participants, perhaps of another age, socioeconomic status (SES), or culture.. repeating the procedures and methods of a study with different participants—is often a sixth and crucial step. Scientists study the reports of other scientists and build on what has gone before. Conclusions are revised, refined, rejected, or confirmed after replication.

cross-sectional research A research design that compares people who differ in age but not in other important characteristics.

The quickest and least expensive way to study development over time is with cross-sectional research, in which groups of people of one age are compared with people of another age. Cross-sectional design seems simple. However, it is difficult to ensure that the various groups being compared are similar in every way except age. cross-sectional research is accurate about the difference between the average responses of people at one age compared to people of another age. In this study, if the research is carefully done, the results reveal exactly how many people are married at every age. However, it does not prove why marriage rates change with age, or what will happen in the future.

The speed and timing of impairments or improvements vary as well. Some changes are sudden and profound because of a

critical period, a time when something must occur for normal development, or the only time when an abnormality can occur. For instance, the critical period for humans to grow arms and legs, hands and feet, fingers and toes is between 28 and 54 days after conception. After day 54, that critical period is over. Time when a particular development must occur. If it does not, as when something toxic prevents that growth, then it cannot develop later.

life span perspective

development is multi-directional, multi-contextual, multi-cultural, and plastic

The two most influential factors that increased the rate of college attendance for low-SES young adults were

excellent education before high school and neighbors who were encouraging and friendly. High schools mattered, but they did not deserve most of the blame or credit.

Overweight Children and Adult Health

in some regions in Africa, about one of every ten newborns dies in the first days of life, with low birthweight (below 2,500 grams, 5½ pounds) a common cause (Grady et al., 2017). A century ago, death of underweight babies led to an untested assumption that is still held by some adults: that overweight children are healthier. results were predicatble. The notion that underweight children are more likely to die led to an unexamined assumption: Heavy children are healthy children Sixty years ago, another untested assumption was that heart attacks could not be prevented. In 1948, scientists decided to study more than 5,000 adults in Framingham, Massachusetts, to see how their health in adulthood affected them later on (Levy & Brink, 2005; Mahmood et al., 2014). They collected data (step 3) and drew conclusions (step 4) that have revolutionized adult behavior. Because of that study (since replicated hundreds of times), cigarette smoking is down, exercise is up, and doctors monitor blood pressure, weight, and cholesterol. Overweight is now recognized as a risk factor for heart disease and many other conditions. Fatal heart attacks were only one-third as common in 2017 as in 1950, with reductions particularly apparent for men aged 40-60 (National Center for Health Statistics, 2017). Obesity is now considered "a chronic progressive relapsing disease" that often begins in childhood and continues lifelong That research led to a new question: Is childhood obesity a health risk, too? This question (step 1) led to a hypothesis (step 2) that childhood overweight impairs adult health, which many believe is already proven. For instance, a poll found that most Californians consider childhood obesity "very serious," with one-third of them rating poor eating habits as riskier to child health than drug use or violence (Hennessy-Fiske, 2011). But science is needed to confirm or refute that hypothesis. Research (step 3) needs to examine adult health in people who had been weighed and measured in childhood. Four teams of scientists did exactly that. They found that most people (83 percent) maintained their relative weight (see Figure 1.2a); thus, most overweight children became overweight adults and risked heart disease because of it. A new question arose (step 1). What about overweight children who become normal-weight adults? That led to a new hypothesis (step 2): Childhood obesity predicts heart attacks, strokes, diabetes, and early death in adulthood, even if the person slims down. The researchers measured health in normal-weight adults who had been overweight children (step 3). The data (step 4) (see Figure 1.2b) found that the hypothesis was false: Those who had slimmed down by adulthood were not at high risk of disease (Juonala et al., 2011). Proving a hypothesis false is as useful for scientists as proving it true. In this case, childhood overweight is not a curse—welcome news leading to more studies. Other research finds that overweight children are at risk for some, but not all, measures of poor health (Ajala et al., 2017).

Statistical Measures Often Used to Analyze Search Results

page 29

Developmentalists use a metaphor for two kinds of children,

those who seem to blossom no matter what kind of child rearing they experience, and those who need intense care—and wither without it. Some are like dandelions—hardy, growing and thriving in good soil or bad, with or without ample sun and rain. Others are like orchids—quite wonderful, but only when ideal growing conditions are met

The study of human development is a science that seeks to

understand how people change or remain the same over time. As a science, it begins with questions and hypotheses and then gathers empirical data. Replication confirms, modifies, or refutes conclusions.

Evolutionary theory in developmental psychology has intriguing explanations for many phenomena:

women's nausea in pregnancy, 1-year-olds' attachment to their parents, adolescent rebellion, emerging adults' sexual passions, parents' investment in their children, and the diseases of late adulthood. All of these interpretations are controversial. Evolutionary explanations for male-female differences are particularly hotly disputed (Ellemers, 2018). Nonetheless, this theory provides many hypotheses to be explored.

Another influential theory, behaviorism,

"began with a healthy skepticism about introspection" in direct opposition to the psychoanalytic emphasis on unconscious, hidden urges (differences are described in Table 1.5) (Staddon, 2014). Behaviorists emphasize nurture, including the social context and culture but especially the immediate responses from other people to whatever a person does. A theory of human development that studies observable actions. Behaviorism is also called learning theory because it describes how people learn to do what they do.

Another influential context is economic, reflected in a person's socioeconomic status, abbreviated SES.

(Sometimes SES is called social class, as in middle class or working class.) SES reflects income and much more, including occupation, education, and neighborhood. A person's position in society as determined by income, occupation, education, and place of residence. (Sometimes called social class.) SES brings opportunities or limitations—all affecting housing, health, nutrition, knowledge, and habits. Poverty is a developmental issue as well as a personal one.

The Life-Span Perspective

1. The assumption that growth is linear and that progress is inevitable has been replaced by the idea that both continuity (sameness) and discontinuity (sudden shifts) are apparent at every age. A critical period is a time when something must occur or when an abnormality might occur. 4. Urie Bronfenbrenner's ecological-systems approach notes that each of us is situated within larger systems of family, school, community, and culture, as well as part of a historical cohort. Changes in the context affect all other aspects of the system. 5.Certain experiences or innovations shape people of each cohort because they were the same age when significant historical events and innovations occurred. Socioeconomic status (SES) affects each child's opportunities, health, and education. 6. Culture includes beliefs and patterns; ethnicity refers to ancestral heritage. Race is a social construction, not a biological one. Differences are not deficits; they are alternate ways to think or act. 7. Development is plastic, which means that change is ongoing, even as some things do not change.

marijuana

2017 recreational marijuana use became legal in Uruguay and in 12 U.S. states, with medical use permitted in several others. A group of doctors advocates legalization of marijuana for reasons related to human development: They say it would be easier to keep drugs from children, to prevent teenagers from harming their brains, and to improve family life if marijuana potency were regulated and users never put in jail. Adolescents are particularly affected by historical shifts, including those regarding marijuana use. In 1978, only 12 percent of high school students thought regular use of marijuana was a "great risk," and more than half had tried the drug. Thirteen years later, 80 percent thought there was "great risk" in regular use, and only 20 percent had tried it.

Birth of a Neuron

A decade ago, neuroscientists thought that adult brains lost neurons, with age or alcohol, but never gained them. Now we know that precursors of neurons arise in the lateral ventricles (bright blue, center) to become functioning neurons in the olfactory bulb (for smell, far left) and the hippocampus (for memory, the brown structure just above the brain stem). Adult neurogenesis is much less prolific than earlier in life, but the fact that it occurs at all is astounding.

social learning theory A theory that emphasizes the influence of other people. Even without reinforcement, people learn via role models. (Also called observational learning.)

A major extension of behaviorism is social learning theory, first described by Albert Bandura (b. 1925). This theory notes that, because humans are social beings, they learn from observing others, even without personally receiving any reinforcement (Bandura, 1977, 2006). Albert Bandura's famous experiment. For example, children who witness domestic violence are influenced by it. As differential susceptibility and multi-contextualism would predict, the particular lesson learned depends on each individual's genes and experiences. If the father of three boys often hits their mother, one son might admire the abuser, another might try to protect the victim, and the third might disappear when fighting begins.

EPIGENETICS

A new discipline that is related to nature and nurture is epigenetics, which explores the many ways in which environmental forces alter genetic expression. Neuroscientists have shown that loneliness, for example, can literally change structures in the brain. epigenetics The study of how environmental factors affect genes and genetic expression—enhancing, halting, shaping, or altering the expression of genes. "there are, indeed, individuals whose genetics indicate exceptionally high risk of disease, yet they never show any signs of the disorder"

ECOLOGICAL SYSTEMS

A perspective on human development that considers all of the influences from the various contexts of development. (Later renamed bioecological theory.) ecognizes three nested levels that surround individuals and affect them Most obvious are microsystems, each person's immediate surroundings, such as family and peer group. Beyond the microsystems are the exosystems (local institutions such as school and church), and beyond that are macrosystems (the larger social setting, including cultural values, economic policies, and political processes).

quantitative research Research that provides data expressed with numbers, such as ranks or scales.

A second caution concerns quantitative research (from the word quantity). Quantitative research data can be categorized, ranked, or numbered, and thus is easily translated across cultures and for diverse populations. One example of quantitative research is the use of children's school achievement scores to compare the effectiveness of education within a school or a nation. Since quantities can be easily summarized, compared, charted, and replicated, many scientists prefer quantitative research. Statistics require numbers. Quantitative data are easier to replicate (Creswell, 2009). However, when data are presented in categories and numbers, some nuances and individual distinctions are lost.

theory and hypothesis

A theory is a comprehensive and organized explanation of many phenomena; a hypothesis is more limited and may be proven false. Theories are general; hypotheses are specific. Theories sharpen perceptions and organize the thousands of behaviors we observe every day.

survey A research method in which information is collected from a large number of people by interviews, written questionnaires, or some other means.

A third research method is the survey, in which information is collected from many people, often by asking them directly. This is a quick way to obtain data. It is better than assuming that the experiences and attitudes of people we happen to know are valid for everyone. although surveys are quick and direct, they are not always accurate. people lie There is another problem with surveys: People do not want to admit whatever they are ashamed of, and many people want to say what they think the researcher wants to hear. This is a major problem in political polling: Most adults say they will vote, even if they will not. Inaccuracy on surveys may harm development. Thus, the U.S. Department of Agriculture developed, tested, and revised the 18 questions of the Food Security Scale (Coleman-Jensen et al., 2017). The survey is accurate when answered honestly, but it is not quick to administer and score. Instead, pediatricians use a briefer version (Council on Community Pediatrics, 2015). Parents answer yes or no to these two statements: The food we bought just didn't last and we didn't have money to get more. We worried whether the food we bought would run out before we got money to buy more. It matters whether this survey asks "yes or no" or "often true, sometimes true, or never true" Accuracy depends not only on the wording of the questions but also on the people who ask and answer.

dynamic-systems approach, a framework that many contemporary developmentalists use.

A view of human development as an ongoing, ever-changing interaction between the physical, cognitive, and psychosocial influences.. The idea behind this approach is that human development is an ongoing, ever-changing interaction between the individual and all the systems, domains, and cultures. a useful strategy for developing motor skills in children with autism spectrum disorder (described in Chapter 7) is to think of the dynamic systems that undergird movement—the changing physical and social contexts (Lee & Porretta, 2013). Systematically considering contexts helps such children—not to make the autism disappear (past conditions are always influential) but to improve the child's ability to function. That's plasticity.

scientific method

A way to answer questions using empirical research and data-based conclusions. not fool proof

frued on development theorgy (page 22)

According to Freud, development in the first six years occurs in three stages, each characterized by sexual pleasure centered on a particular part of the body. Infants experience the oral stage because their erotic body part is the mouth, followed by the anal stage in early childhood, with the focus on the anus. In the preschool years (the phallic stage), the penis becomes a source of pride and fear for boys and a reason for sadness and envy for girls. In middle childhood comes latency, a quiet period that ends with the genital stage at puberty. Freud thought that the genital stage continued throughout adulthood, which makes him the most famous theorist who thought that development stopped after puberty (see Table 1.4). As you remember, this assumption is no longer held by developmentalists. Freud maintained that at each stage, sensual satisfaction (from the mouth, anus, or genitals) is linked to developmental needs, challenges, and conflicts. How people experience and resolve these conflicts—especially those related to weaning (oral), toilet training (anal), male roles (phallic), and sexual pleasure (genital)—determines personality then, because "the early stages provide the foundation for adult behavior" (Salkind, 2004, p. 125).

experiment A research method in which the researcher adds one variable (called the independent variable) and then observes the effect on another variable (called the dependent variable) in order to learn if the independent variable causes change in the dependent variable.

An experiment tests a hypothesis. In the social sciences, experimenters typically impose a particular treatment on a group of participants (formerly called subjects) or expose them to a specific condition and then note whether their behavior changes. the experimenters manipulate an independent variable, the imposed treatment or special condition (also called the experimental variable). (A variable is anything that can vary.) They note whether this independent variable affects whatever they are studying, called the dependent variable, which depends on the independent variable. To follow up on the observation study above, researchers could experiment. For example, they could assess the social skills (dependent variable) of hundreds of children in the first week of school and then require parents in half of the classes to linger at drop-off (independent variable, experimental group), and in the other classes, require parents to leave immediately. Critical thinking is needed.

quiz

Answer to Observation Quiz (from page 12) Because surveys rarely ask children their opinions, and the youngest cohort on this graph did not reach adulthood until about 2005. Answer to Observation Quiz (from page 17) A snapshot is only one moment, but her arm around him, and her happy, relaxed expression suggests a warm father-daughter relationship. At this point, he already had symptoms of the tuberculosis that killed him. Answer to Observation Quiz (from page 25) Both are balding, with white beards. Note also that none of the other theorists in this chapter has a beard—a cohort difference, not an ideological one. Answer to Observation Quiz (from page 34) Of course, much changed and much did not change, but evident in the photos is continuity in Sarah-Maria's happy smile and discontinuity in her hairstyle (which shows dramatic age and cohort changes).

Every topic in human development is controversial, with opposing perspectives and opinions.

As a scientist and a textbook author, I often report statistics and try to stick to evidence, but I am aware of confirmation bias, that humans tend to seek evidence that confirms what they already think (Del Vicario et al., 2017). To avoid that bias, scientists check facts and seek contrary evidence, keeping an open mind to see where the data lead. Critical thinking is my goal, and the goal of the scientific method, but my opinions may creep into my conclusions. I hope you will seek out the evidence yourself, especially when you disagree with my perspective.

To rein in personal biases and avoid misinterpretations, researchers follow the scientific method

Begin with curiosity. Pose a question, guided by theory, research, or observation. Develop a hypothesis. Shape the question into a testable hypothesis. Test the hypothesis. Gather empirical evidence (data). Draw conclusions. Use evidence to support or refute the hypothesis. Report the results. Share data, limitations, and conclusions.

evolutionary theory When used in human development, the idea that many current human emotions and impulses are a legacy from thousands of years ago.

Charles Darwin's basic ideas were first published 150 years ago (Darwin, 1859), but serious research on human development inspired by evolutionary theory is quite recent. According to evolution, every species strives to survive and reproduce. That is true for humans, too. Consequently, many human impulses, needs, and behaviors evolved to help people survive and thrive over the past 100,000 years (Konner, 2010). To understand contemporary human development, this theory contends, we must consider what humans needed thousands of years ago. Evolutionary theory notes that, although fear of snakes, or blood, or thunder is irrational, some of our best human qualities, such as cooperation, spirituality, and self-sacrifice, also evolved thousands of years ago, when groups of people survived because they cared for one another. Childhood itself, particularly the long period when children depend on others while their brains grow, can be explained via evolution Notice that human mothers welcome child-rearing help from fathers, other relatives, and even strangers. Shared child rearing, called allocare, allows women to have children every two years or so, unlike chimpanzees, who space births four or five years apart (Hrdy, 2009). The reason, according to this theory, is that Homo sapiens (unlike all the other Homo species) found that allocare aided survival and reproduction. The result: almost 8 billion of our species alive today and only about 200,000 chimpanzees, a ratio of 35,000 to 1.

Three Types of Learning Behaviorism is also called learning theory because it emphasizes the learning process, as shown here. Depending on the responses of other people, and the constraints of the culture, behaviorists believe that anything can be learned.

Classical conditioning, Operant conditioning, Social learning

The Scientific Method

Commonly used research methods are scientific observation, the experiment, and the survey. Each can provide insight and discoveries, yet each is limited. Developmentalists study change over time, often with cross-sectional and longitudinal research. Ideally, results from both methods are combined in cross-sequential analysis. A correlation shows that two variables are related, not that one causes the other: Both may be caused by a third variable. Quantitative research provides numerical data. This makes it best for comparing contexts and cultures via verified statistics. By contrast, more nuanced data come from qualitative research, which reports on individual lives. Ethical behavior is crucial in all of the sciences. Results must be fairly gathered, reported, and interpreted. Participants must understand and consent to their involvement. Scientists continue to study, report, discuss, and disagree—and eventually reach conclusions that aid all humankind.

Many of Freud's followers became famous theorists themselves. The most notable for our study of human development was

Erik Erikson (1902-1994), who described eight developmental stages, each characterized by a challenging crisis (summarized in Table 1.4). Although Erikson's first five stages build on Freud's theory, he added three adult stages, perhaps because of his own experience. He was a wandering artist in Italy, a teacher in Austria, and a Harvard professor in the United States. Erikson named two polarities at each stage (which is why the word versus is used in each), but he recognized that many outcomes between these opposites are possible (Erikson, 1993a). For most people, development at each stage leads to neither extreme. For instance, the generativity-versus-stagnation stage of adulthood rarely involves a person who is totally stagnant—no children, no work, no creativity. Instead, most adults are somewhat stagnant and somewhat generative. As the dynamic-systems theory would predict, the balance may shift year by year. Erikson, like Freud, believed that adult problems echo childhood conflicts. For example, an adult who cannot form a secure, close relationship (intimacy versus isolation) may not have resolved the crisis of infancy (trust versus mistrust). However, Erikson's stages differ significantly from Freud's in that they emphasize family and culture, not sexual urges. He called his theory epigenetic, partly to stress that genes and biological impulses are powerfully influenced by the social environment.

empirical evidence

Evidence that is based on observation, experience, or experiment; not just theory or opinion. This makes it science-based.

There is increasing evidence of differential susceptibility—that is, the idea that the effect of any experience differs from one person to another because of the particular genes each person has inherited. The idea that people vary in how sensitive (for better or worse) they are to particular experiences, either because of their genes or because of their past experiences. (Also called differential sensitivity.)

For instance, if toddlers inherit the tendency to be disruptive, depressed, antisocial, or anxious, they benefit from a mother who provides structure and guidance. On the other hand, if a child is at low genetic risk for those problems, having such a mother might not matter, or might even be harmful

culture

For social scientists, culture is "the system of shared beliefs, conventions, norms, behaviors, expectations and symbolic representations that persist over time and prescribe social rules of conduct" One assumption is evident if the word culture is used to refer to large groups of other people, as in "Asian culture" or "Hispanic culture." That invites stereotyping and prejudice, since such large groups include people of many backgrounds.

Russian developmentalist Lev Vygotsky (1896-1934) was a leader in describing the interaction between culture and education

He noticed that adults from the many cultures of the Soviet Union (Asians and Europeans of many religions) taught their children whatever beliefs and habits they might need as adults within their local community. believed that guided participation is a universal process used by mentors to teach cultural knowledge, skills, and habits. Guided participation can occur via school instruction but more often happens informally, through "mutual involvement in several widespread cultural practices with great importance for learning: narratives, routines, and play" My grandson's third-grade teacher shakes each child's hand at the end of the day, smiles, and expects her students to look at her and say goodbye. In other cultures, this would not happen.

If you doubt that historical trends and events touch individuals, consider first names

If you know someone named Emma, she is probably young—Emma is the most popular name now but was not in the top 100 until 1993. Your own name is influenced by history; your reaction is yours. Nurture and nature again.

Freud

In addition to being the world's first psychoanalyst, Sigmund Freud was a prolific writer. His many papers and case histories, primarily descriptions of his patients' symptoms and sexual urges, helped make the psychoanalytic perspective a dominant force for much of the twentieth century. Psychoanalytic theory originated with Sigmund Freud (1856-1939), an Austrian physician who treated patients suffering from mental illness. He listened to their dreams and fantasies and constructed an elaborate, multifaceted theory.

cognitive theory A theory of human development that focuses on how people think. According to this theory, our thoughts shape our attitudes, beliefs, and behaviors.

In cognitive theory, each person's ideas and beliefs are crucial. This theory has dominated psychology since about 1980 and has branched into many versions. The word cognitive refers not just to thinking but also to attitudes, beliefs, and assumptions.

developmentalists are reluctant to specify chronological ages for any period of development, since time is only one of many variables that affect each person. However, age is a crucial variable, and development can be segmented into periods of study. Approximate ages for each period are given here.

Infancy- 0 to 2 years Early childhood 2 to 6 years Middle childhood 6 to 11 years Adolescence 11 to 18 years Emerging adulthood 18 to 25 years Adulthood 25 to 65 years Late adulthood 65 years and older

psychoanalytic theory A theory of human development which contends that irrational, unconscious drives and motives underlie human behavior.

Inner drives and motives are the foundation of psychoanalytic theory. These basic underlying forces are thought to influence every aspect of thinking and behavior, from the smallest details of daily life to the crucial choices of a lifetime. developed by freud

Piaget's Periods of Cognitive Development (page 26)

Intellectual advancement occurs because humans seek cognitive equilibrium, that is, a state of mental balance. An easy way to achieve this balance (called assimilation) is to interpret new experiences through the lens of preexisting ideas. For example, infants discover that new objects can be grasped in the same way as familiar ones; adolescents explain the day's headlines as evidence that supports their existing worldviews; older adults speak fondly of the good old days as embodying values that should endure. Another influential cognitive theory, called information processing, is not a stage theory but rather provides a detailed description of the steps of cognition, focusing on what happens in the brain to cause intellectual growth. This theory is especially useful in understanding thinking in middle childhood and late adulthood, as you will see in Chapters 7 and 14. Thoughts influence emotions and actions. This is sometimes called a constructive view of human cognition, because people of all ages build their understanding of themselves and their world, combining their experiences and their interpretations.

Development Is Multi-Contextual

It takes place within many contexts, including physical surroundings (climate, noise, population density, etc.) and family configurations (married couple, single parent, cohabiting couple, extended family, etc.). Each context influences development, sometimes for a moment, sometimes for years.

Nature-Nurture

Nature refers to the influence of the genes that people inherit. Nurture refers to environmental influences, beginning with the health and diet of the embryo's mother and continuing lifelong, including family, school, community, culture, and society. nature In development, nature refers to genes. Thus, traits, capacities, and limitations inherited at conception are nature. nurture In development, nurture includes all environmental influences that occur after conception, from the mother's nutrition while pregnant to the culture of the nation. The nature-nurture issue has many other names, among them heredity vs. environment and maturation vs. learning. Under whatever name, the basic question is: How much of any characteristic, behavior, or emotion is the result of genes and how much is the result of experience? Neither extreme is accurate. The question is "how much," not "which," because both genes and experience affect every characteristic: Nature always affects nurture, and then nurture affects nature.

correlation Usually a number between +1.0 and -1.0 that indicates whether and how much two variables are related. Correlation indicates whether an increase in one variable will increase or decrease another variable. Correlation indicates only that two variables are somehow related, not that one variable causes the other to increase or decrease.

Probably the most common mistake in interpreting research is confusing correlation with causation. A correlation exists between two variables if one variable is more (or less) likely to occur when the other does. A correlation is positive if both variables tend to increase together or decrease together, negative if one variable tends to increase while the other decreases, and zero if no connection is evident. Many correlations are unexpected. correlation is not causation. Just because two variables are correlated does not mean that one causes the other—even if it seems logical that it does. It proves only that the variables are connected somehow.

Theories of Human Development

Psychoanalytic theory emphasizes that adult actions and thoughts originate from unconscious impulses and childhood conflicts. Freud theorized that sexual urges arise during three stages of childhood; Erikson described eight successive stages of development, each involving a crisis to be resolved, including three in adulthood. Behaviorists, or learning theorists, emphasize conditioning—a lifelong learning process in which an association between one stimulus and another (classical conditioning) or the consequences of reinforcement and punishment (operant conditioning) guide behavior. Social learning theory recognizes that people learn by observing others, even if they themselves have not been reinforced or punished. Children are particularly susceptible to social learning, but all humans are affected by what they notice in other people. Cognitive theorists believe that thoughts and beliefs powerfully affect attitudes, actions, and perceptions, and those affect behavior. Piaget proposed four age-related periods of cognition. Information processing looks more closely at the relationship between brain activity and thought. Evolutionary theory contends that contemporary humans inherit genetic tendencies that have fostered survival and reproduction of the human species for tens of thousands of years. Through selective adaptation, the fears, impulses, and reactions that were useful 100,000 years ago continue to this day.

Accordingly, the American Association for the Advancement of Science (AAAS, a national organization of 40,000 scientists from every discipline, including the many who study human development) adopted a statement on scientific freedom and responsibility. Both are crucial for good science:

Scientific freedom and scientific responsibility are essential to the advancement of human knowledge for the benefit of all. Scientific freedom is the freedom to engage in scientific inquiry, pursue and apply knowledge, and communicate openly. This freedom is inexorably linked and must be exercised in accordance with scientific responsibility. Scientific responsibility is the duty to conduct and apply science with integrity, in the interest of humanity, in a spirit of stewardship for the environment, and with respect for human rights. [Jarvis, 2017, p. 462]

cross-sequential research A hybrid research design that includes cross-sectional and longitudinal research. (Also called cohort-sequential research or time-sequential research.)

Scientists now have a third strategy, a sequence of data collection that combines cross-sectional and longitudinal research. This combination is called cross-sequential research (also referred to as cohort-sequential or time-sequential research). In sequential designs, researchers study people of different ages (a cross-sectional approach), follow them for years (a longitudinal approach), and then combine the results. lets researchers compare findings for, say, 6-year-olds with findings for the same individuals at birth as well as with data from people who were 6 long ago, who are now ages 12, 18, or even much older (see Figure 1.10). Cross-sequential research is complicated, in recruitment and analysis, but it lets scientists disentangle age from history. The first well-known cross-sequential study (the Seattle Longitudinal Study) found that some intellectual abilities (vocabulary) increase even after age 60, whereas others (speed) start to decline at age 30 (Schaie, 2005/2013), confirming that development is multi-directional. This study also discovered that declines in adult math ability are more closely related to education than to age, something neither cross-sectional nor longitudinal research alone could reveal.

multi-cultural approach is crucial.

The difference-equals-deficit error is one reason a multi-cultural approach is crucial. Various ways of thinking or acting are not necessarily wrong or right, better or worse. The scientific method, which requires empirical data, is needed for accurate assessments. difference does not equal deficit.

Each academic discipline and professional society that is involved in the study of human development has a code of ethics (a set of moral principles).

The idea is that scientists need to adhere to high standards, and society needs to allow scientists the freedom to do so. Ethical standards and codes are increasingly stringent. Most educational and medical institutions have an Institutional Review Board (IRB), a group that permits only research that follows certain guidelines. One crucial focus is on the well-being of the participants in a study: They must understand and consent to their involvement, and the researcher must keep results confidential and must ensure that no one is seriously or permanently harmed. slow down science Our job as scientists is to discover truths about the world. We generate hypotheses, collect data, and examine whether or not the data are consistent with those hypotheses . . . [but we] often lose sight of this goal, yielding to pressure to do whatever is justifiable to compile a set of studies we can publish. This is not driven by a willingness to deceive but by the self-serving interpretation of ambiguity . . . [Simmons et al., 2011, p. 1359, 1365]

operant conditioning. The learning process that reinforces or punishes behavior. (Also called instrumental conditioning.)

The most influential North American behaviorist, B. F. Skinner (1904-1990), was inspired by Pavlov (Skinner, 1953). Skinner agreed that classical conditioning explains some behavior. Then he went further, experimenting to demonstrate another type of conditioning, operant conditioning. B. F. Skinner is best known for his experiments with rats and pigeons, but he also applied his knowledge to human behavior. Pleasant consequences are sometimes called rewards, and unpleasant consequences are sometimes called punishments. Behaviorists hesitate to use those words, however, because what people think of as punishment can actually be a reward, and vice versa. Any consequence that follows a behavior and makes the person (or animal) likely to repeat that behavior is called a reinforcement, not a reward. Once a behavior has been conditioned, humans and other creatures will repeat it even if reinforcement occurs only occasionally. Similarly, an unpleasant response makes a creature less likely to repeat a certain action.

classical conditioning According to behaviorism, the processes of learning. The word conditioning emphasizes the importance of repeated experiences, as when an athlete conditions his or her body by training day after day.

The specific laws of learning apply to conditioning, the processes by which responses become linked to particular stimuli. Just as marathon runners try to condition themselves with daily runs for months, people are gradually conditioned to learn a particular behavior.

Social constructions

Thus, culture is far more than food, clothes, or customs; it is a set of ideas that people share. This makes culture a powerful social construction, a concept constructed, or made, by a society. Social constructions affect how people think, what they do, and what they value. An idea that is built on shared perceptions, not on objective reality. Because culture is so basic to thinking and emotions, people are usually unaware of their social constructions.

language and culture

To appreciate that culture is a matter of beliefs and values, not superficial differences, consider language again. Of course, people speak distinct languages, but that itself is not a cultural difference. However, some people are offended by words that other people proudly say. That is cultural.

In addition to conducting observations, experiments, and surveys, developmentalists must measure how people change or remain the same over time, as our definition stresses.

To capture that dynamism, developmental researchers use one of three basic research designs: cross-sectional, longitudinal, or cross-sequential.

longitudinal research A research design that follows the same individuals over time.

To help discover whether age itself, not cohort, causes a developmental change, scientists undertake longitudinal research. This requires collecting data repeatedly on the same individuals. Back to the feature on pages 5-6: Because parents are much more aware of the lifelong problems of obesity, the current cohort of overweight children and adolescents may more often become normal-weight adults (Arigo et al., 2016). Cross-sectional research suggests that is happening, but only longitudinal research will prove it. For insight about the life span, the best longitudinal research follows the same individuals from infancy to old age. Long-term research requires patience and dedication from a team of scientists, but it can pay off. For example, a longitudinal study of 790 low-SES children in Baltimore found that only 4 percent had graduated from college by age 28 (Alexander et al., 2014). longitudinal research has a problem, something already mentioned: the historical context. Science, popular culture, and politics change over time, and each alters the experiences of a child. Data collected on children born decades ago may not be relevant for today.

a contextual approach to development requires simultaneous consideration of many systems.

Two contexts—historical and socioeconomic—are crucial in understanding all of the systems of life-span development, yet they are often ignored. They merit explanation now.

The most famous cognitive theorist was Jean Piaget (1896-1980), who began by observing his own three infants and later studied thousands of older children

Unlike other scientists of the early twentieth century, Piaget realized that babies are curious and thoughtful, creating their own interpretations about their world. From this work, Piaget developed the central thesis of cognitive theory: How people think (not just what they know) changes with time and experience, and then human thinking influences actions. Piaget maintained that cognitive development occurs in four major age-related periods, or stages: sensorimotor, preoperational, concrete operational, and formal operational (see Table 1.6).

systems

Urie Bronfenbrenner says each person is significantly affected by interactions among a number of overlapping systems, which provide the context of development. Microsystems—family, peer group, classroom, neighborhood, house of worship—intimately and immediately shape human development. Surrounding and supporting the microsystems are the exosystems, which include all of the external networks, such as community structures and local educational, medical, employment, and communications systems, that affect the microsystems. Influencing both of these systems is the macrosystem, which includes cultural patterns, political philosophies, economic policies, and social conditions. Mesosystems refer to interactions among systems, as when parents and teachers coordinate to educate a child. Bronfenbrenner eventually added a fifth system, the chronosystem, to emphasize the importance of historical time. stressed the chronosystem (literally, "time system"), which encompasses historical conditions that affect each person. Further, to stress the dynamic interaction among all of the systems, he included a fifth system, the mesosystem, consisting of the connections between and among the other systems.

All people born within a few years of one another are said to be a cohort,

a group defined by its members' shared age. Cohorts travel through life together, affected by the interaction of their chronological age with the values, events, technologies, and culture of the era. People born within the same historical period who therefore move through life together, experiencing the same events, new technologies, and cultural shifts at the same ages.

The science of human development seeks to understand how and why people—

all kinds of people, everywhere, of every age—change over time. The goal is for everyone, of all ages, cultures, and aspirations, to have a happy, productive, and meaningful life.

The life-span perspective takes into account

all phases of life (not just the first two decades, which were once the sole focus of developmental study), and all aspects of development (not just physical development, once the main focus). this perspective has led to the realization that human development is multi-directional, multi-contextual, multi-cultural, and plastic. An approach to the study of human development that includes all phases, from conception to death.

race

also a social construction—and a misleading one. There are good reasons to abandon the term and good reasons to keep it The concept that some people are distinct from others because of physical appearance, typically skin color. Social scientists think race is a misleading idea, although race can be a powerful social construction, not based in biology. Genetic analysis confirms that the biological concept of race is inaccurate, especially when based on skin color. A study of the genes for skin tones found marked diversity among people from Africa. The lead scientist explained, "There is so much diversity in Africans that there is no such thing as an African race" (Tishkoff, quoted in Gibbons, 2017, p. 158). Indeed, dark-skinned Australians or Maori in New Zealand share neither culture nor ethnicity with Africans. A study of East Asians found 20 genetic variants (most of them rare) that affect their skin color (Hider et al., 2013). The term race is used to categorize people via physical markers, particularly outward appearance. Historically, most North Americans believed that race was the outward manifestation of inborn biological differences. Fifty years ago, races were categorized by skin color: white, black, red, and yellow (Coon, 1962). Since race is a social construction that leads to racism, most nations no longer refer to racial groups. Only 15 percent of nations use the word race on their census forms (Morning, 2008). The United States is the only nation whose census distinguishes race and ethnicity, stating that Hispanics "may be of any race." Such distinctions are not always clear or consistent: Between the 2000 U.S. Census and 2010 U.S. Census, 6 percent of individuals changed their racial or ethnic identification (Liebler et al., 2017). Because of the way human cognition works, the terminology in the U.S. Census encourages stereotyping (Kelly et al., 2010). As one scholar explains: The United States' unique conceptual distinction between race and ethnicity may unwittingly support the longstanding belief that race reflects biological difference and ethnicity stems from cultural difference . . . [and] preclude understanding of the ways in which racial categories are also socially constructed. Two political scientists studying criminal justice found that people who claim to be color-blind display "an extraordinary level of naiveté" A person's concept of race depends partly on their culture, cohort, and—particularly relevant to a life-span view—age. Adolescents of minority ethnicity who are proud of their racial identity are likely to achieve academically, resist drug addiction, and feel better about themselves (Crosnoe & Johnson, 2011; Zimmerman et al., 2013; Wittrup et al., 2016).

Neuroscientists are among the most recent to

apply a life-span perspective, recognizing that the connections in the brain are plastic and vary from one person to another

qualitative research (from the word quality)―

asking open-ended questions, reporting answers in narrative (not numerical) form. Qualitative researchers are "interested in understanding how people interpret their experiences, how they construct their worlds . . ." (Merriam, 2009, p. 5). qualitative research Research that considers individual qualities instead of quantities (numbers). reflects cultural and contextual diversity, but it is also more vulnerable to bias and harder to replicate. Both types of research, and research that combines the two, are needed

Ivan Pavlov was a physiologist who received the Nobel Prize in 1904 for his research on

digestive processes. It was this line of study that led to his discovery of classical conditioning, when his research on dog saliva led to insight about learning. Ivan Pavlov (1849-1936), a Russian medical doctor born in poverty who won a Nobel Prize for his work on digestion, noticed something in his experimental dogs that awakened his curiosity (step 1 of the scientific method) (Todes, 2014). The dogs drooled not only when they saw and smelled food but also when they heard the footsteps of the attendants who brought the food. This observation led Pavlov to hypotheses and experiments in which he conditioned dogs to salivate when they heard a specific noise (steps 2 and 3). Pavlov began by sounding a tone just before presenting food. After a number of repetitions of the tone-then-food sequence, dogs began salivating at the sound, even when there was no food. This simple experiment demonstrated classical conditioning, when a person or animal learns to associate a neutral stimulus (the sound) with a meaningful stimulus (the food), gradually reacting to the neutral stimulus in the same way as to the meaningful one (step 4). The fact that Pavlov published (step 5) in Russian is one reason his research took decades to reach the United States (Todes, 2014).

what is often repeated that "the United States is becoming more diverse," a phrase that usually refers only to ethnic diversity and not to

economic and religious diversity (which are also increasing and merit attention). From a developmental perspective, two other diversities are also important — age and region, as shown below.

implications of what is studied

family planning, gun control, unknown unknowns

Nature (genes) and nurture (environment) always

interact, and each human characteristic is affected by that interaction. In differential susceptibility, both genes and experiences can make some people change when others remain unaffected.

The most difficult part of the scientific method is to recognize that questions asked (step 1) and conclusions drawn (step 4) are

limited by the people who designed the research.

Development over the life span is

multi-directional, multi-contextual, multi-cultural, and plastic. developmental study is a science. It depends on theories, data, analysis, critical thinking, and sound methodology, like every other science.

difference-equals-deficit error

our personal pride becomes destructive if it reduces respect and appreciation. Developmentalists recognize this difference-equals-deficit error, the mistaken belief that people who are different from us are thereby deficient, which means lacking in some important way. Too quickly and without thought, differences are assumed to be problems. The mistaken belief that a deviation from some norm is necessarily inferior.

According to behaviorism,

people are never too old to learn. I

Each developmental theory is a systematic statement of

principles and generalizations, providing a framework for understanding how and why people change over the life span. A group of ideas, assumptions, and generalizations about human growth. A developmental theory provides a framework to interpret growth and change. Kurt Lewin (1945) once quipped, "Nothing is as practical as a good theory."

Many scientists believe that psychology is now experiencing a

replication crisis, since many important studies fail to replicate. But some scientists welcome the need for replication. One calls "the replication crisis as among psychological science's finest hours"

scientific observation Watching and recording participants' behavior in a systematic and objective manner—in a natural setting, in a laboratory, or in searches of archival data.

requires researchers to record behavior systematically and objectively. Observations often occur in a naturalistic setting (such as a home, school, or public park), where people behave as they usually do and where the observer is ignored or even unnoticed. Observation can also occur in a laboratory, where scientists record human reactions in various situations, often with wall-mounted video cameras and the scientist in another room. crucial for developing hypotheses.

a particular development occurs more easily—not exclusively—at a certain time. Such a time is called a

sensitive period. A time when a particular developmental growth is most likely to occur, although it may still happen later. An example is found in language. Often in development, individual exceptions to general patterns occur. Accent-free speech usually must be learned before puberty, but exceptional nature and nurture (an adult with excellent hearing and then immersion in a new language) can result in flawless second-language pronunciation Because of sensitive periods for language development, such exceptions are rare. A study of native Dutch speakers who become fluent in English found only 5 percent had truly mastered native English (Schmid et al., 2014). Fluent English speakers who spoke another language first almost always stumbled with idioms, articles, or accents. Sensitive periods occur at many ages, not just early childhood. Consider the best time to learn about cultural differences, or infant care, or calculus: Not childhood!