Part I Introduction Chapter One Defining Development: Science of Human Development seeks to understand how and why people, all kinds of people, everywhere, of every age change over time. It depends on theories, data, analysis, critical thinking, and sound methodology just like every other science.

Scientific Method 1. Begin with curiosity. Pose a question. 2. Develop a hypothesis, a specific prediction that can be tested. 3. Test the hypothesis. Design and conduct research to gather empirical (observable, verifiable) evidence (data). 4. Draw conclusions. Does the research support or negate the hypothesis? 5. Report the results. Results are reported so that others may review or replicate the hypothesis. (Replicate: repeat the procedures and methods of study with different participants.)

SIDS ILLUSTRATION Studies performed by Susan Beal indicate that survival rates are highest among back- sleeping babies. She noted that Chinese infants rarely succumbed to SIDS and developed a hypothesis that it had to do with the fact that Chinese infants were put to sleep on their backs unlike their American and European counterparts who were stomach sleepers. Her initial hypothesis was tested among non-Chinese parents and had favorable results. As it was replicated and continued to confirm her hypothesis that it is the actual sleeping position that matters, she was able to put forth her theory and the Back to Sleep campaign was born in 1994. SIDS illustrate the replication and application of the science of child development?.

Figure of Sleeping Baby Swaddling blanket is not only folded under baby but it is also tied in place.

SIDS Beyond nationality and sleeping position, other risks include low birthweight, a brain- stem abnormality that produces too little of a particular brain chemical (serotonin, a neurotransmitter), cigarette smoking in the household, soft blankets or pillows, and bed- sharing (when infants sleep in their parents’ bed) (Duncan et al., 2010; Ostfeld et al., 2010). Most SIDS victims experienced several risk factors: babies with none of these risks rarely die as a result of SIDS (Ostfeld et al., 2010).

Understanding How and Why It is a science. Use Scientific Method to answer questions. The Nature—Nurture Debate Critical and Sensitive Periods A CASE TO STUDY: Plasticity and David

Nature-Nurture Debate Nature (heredity, maturation) refer to the influence of genes that people inherit. Nurture (environment, learning) refers to environmental influences (health, diet, family, school, culture, and society) that affect development after an individual is conceived. HOW MUCH affect? Not Which. Basic question is: How much of any characteristic, behavior, or emotion results from genes and how much from experience? HOW MUCH not WHICH. Both genes and the environment affect every characteristic. Some scientists believe that how much is not a valid question since it implies proportions, as if each part contributes a share. No genetic or environmental factor acts in isolation. Babies died of SIDS not because nature added to nurture or vice versa, but because of multiplying risks.

Differential Sensitivity Certain genes increase or decrease the likeihood that a child will be affected by the environment. EX: MAOA gene A violent delinquent is often a boy who was beaten in childhood and who lives in a drug- filled, crowded neighborhood (Maas et al., 2008). Researchers found that boys who were mistreated by their parents were about twice as likely to be overly aggressive (to develop a conduct disorder, to be violent, to be antisocial, and eventually to be convicted of a violent crime) if, and only if, they had the low-MAOA gene instead of the high-MAOA one (Caspi et al., 2002). Replications of the Dunedin study have not always confirmed the direct link between MAOA and violence. However, the general finding that genes can act in opposite ways depending on the environment has been confirmed by many other researchers. Social context – pregnant mother’s diet, affection bestowed on infant, intellectual stimulation of early childhood, bullying or friendship in middle childhood – affects how genetic codes work. Inherited risk influences later behavior.

Critical Periods A critical period is the time frame when certain characteristics MUST develop. EX: The human embryo grows arms and legs, hands and feet, fingers and toes, each over a specific few days between 28 and 54 days after conception. After that it is too late. We are unlike insects- we cannot grow new limbs Between 1957 and 1961, thalidomide (antinausea drug) – if pregnant mother ingested this drug during critical period, her baby’s limbs were malformed or absent. If she took the drug only before day 28 after after day 54, no harm occurred.

Sensitive Periods A sensitive period is the time frame when development would most easily occur but if that window of time is missed, it can be made up later. EX: language. If a child does not speak first language between ages 1 and 3, they may do so later but grammar is often impaired. Life has few such critical periods. 9. Why is it important to know when a sensitive period in development occurs? It is important to know when those time frames are in order to provide the most supportive environment for helping a skill, like language, emerge.

Plasticity Idea that abilities, personality, and other human characteristics can change over time. This is especially evident during childhood but older adults are not always "set in their ways." EX: David Case Study There are many constraints on development due to genetic or environmental limits. However, the evidence through research that one can sometimes overcome these limits leads to plasticity. Human traits can be molded like plastic yet maintain a certain durability of identity as does plastic. Change is possible over the life span and development does build on what has come before, for better or worse. Malnourished kids need not become diabetic. An Adult with troubled childhood may become a loving responsive parent. Plasticity works in the other direction also. Gifted at 3 – some giftedness did not endure – children can become ordinary adults.

David

Older Adults are Not Always Set in their Ways

Including All Kinds of People Difference Equals Deficit Error Sex Differences Culture, Ethnicity, And Race Socioeconomic Status Finding the Balance DEDE: Human tendency to notice differences and then to jump to the conclusion that something important is lacking. Every difference is perceived as a deficit. Many diversities are differences to be welcomes not deficits to remedy. Developmental researchers try to avoid this error by studying people of every age and background. There are differences but Similarities among the sexes outweigh the differences.Same foods, same lessons, same clothes sometimes. Culture- system of shared beliefs, conventions, norms, behaviors, expectations, and symbolic representation that presist over time.It is more than food and ritual. It is a social construction – terms constructed by society. Culture affects development in a multitude of interrelated ways, from whether to cover your mouth when laughing to what to eat for breakfast. Book Reading – what did you learn? – US mothers used more nouns than verbs and Chinese mothers stressed action but all parents were using vocabulary and attitudes related to their cultures. Ethnic and Racial Groups – people whose ancestors were born in the same region and who often share a language, culture, and religion. Ethnicity is a social construction. Ethnic identify become more specific when others of the same ethnic group are nearby and when members of other groups focus on differences. Race – group of people who are regarded by themselves or by others as distinct from other groups on the basis of physical appearance – typically skin color. Social scientist reject the concept that race is genetic. SES – sometimes called social class; reflects family income but not income alone, occupation, education, and place of residence. SES affects every aspect of development. Finding the Balance – science of human development attempts to find the right balance between the universal and the particular.

Market in Bangkok, Thailand Compare this floating market in Bangkok to a North American supermarket.

Observing Changes over Time Continuity and Discontinuity, Sudden Eruptions and Gradual Shifts – People do not grow gradually at the same pace (linear growth). Dynamic Systems The Historical Context The Three Domains A VIEW FROM SCIENCE: Mirror Neurons continuity refers to characteristics that are stable over time (e.g., biological sex). discontinuity refers to characteristics unlike those than came before (e.g., speaking a new language, quitting a drug). People do not grow gradually at the same pace (linear growth) nor is growth occurred in distinct stage or steps. See figure 1.4.

Changes Over Time There are gains and losses.

Dynamic Systems The emphasis on the interaction between people and within each person is highlighted by the dynamic-systems theory, which stresses fluctuations and transitions. This is a relatively new approach to the science of development. A view of human development as an ongoing, ever-changing interaction between the physical, cognitive, and psychosocial influences. Development is never static. It is dynamic but is always affected by and affects many systems of development. The word “systems” captures the idea that a change in one aspect of a person, family, or society affects all of the other aspects because each part is connected to all the other parts.

Ecological Systems Model This approach emphasizes the influence of the systems, or contexts, that support the developing person. Urie Bronfenbrenner recommended an ecological-systems approach. According to this model, human development is supported by systems at four nested levels: the microsystem (immediate social setting), the exosystem (local, such as school and church), the macrosystem (cultural values, political processes, economic policies, and social conditions), and the chronosystem, which emphasizes the importance of historical time on development. A fifth system, the mesosystem, connects systems, for example, the interface between home and school. As a reflection of the impact of biology on development, Bronfenbrenner renamed his theory bioecological theory.

The Historical Context A cohort is a group of people born within a few years of each other who tend to share certain historical events and cultural shifts. Members of each cohort are affected by the values, events, technologies, and culture of their era. If you doubt national trends and events touch people, Consider your first name. Look at Table 1.2.

First Names Answers: 1960, 1910, 2010, 1935, and 1985.

The Three Domains Because it is impossible to simultaneously examine all the dynamic changes that occur over time, developmentalists often segment their study into three domains—biosocial, cognitive, and psychosocial. The interaction of the three domains is expressed in the term biopsychosocial. The division of human development into three domains makes it easier to study, but remember that very few factors belong exclusively to one domain or another. Development is not piecemeal but holistic. Each aspect of development is related to all three domains.

Domains of Human Development

Mirror Neurons Mirror neurons are brain cells that respond to the observed actions of others. These neurons, which in the human brain reflect not only the movements but also the intentions, sensations, and emotions of those around us, may help explain autism, language learning, empathy for other people, and how culture is transmitted. Mirror neurons amplify human learning and development. Infants, children, and adults watch what other people do and, neurologically, experience it themselves.

Monkey See, Monkey Do

Using the Scientific Method Observation The Experiment The Survey Studying Development

OBSERVATION There are many ways to test hypotheses. One method is scientific observation of people in their natural environment, in a laboratory setting, or in searches of archival data. Observation is limited in that it does not tell us what causes people to do what they do.

OBSERVATION Observations may take place in a natural setting, in a laboratory, or in searches of archival data. The purpose for being “unobtrusive” is to avoid influencing the behavior of the people you are watching.

SURVEY The survey is a quick and direct way to obtain data. However, it is especially difficult to get valid data from a survey: Some people may refuse to answer, and others may give answers to make themselves look better. The wording and the sequence of the questions also influence survey answers.

OB Scientific Observation as a Way to Test Hypotheses Elections would be easy to predict if people voted as they told survey takers they would! If we want our survey to accurately describe a population, the sample we survey should be selected randomly from the whole population, not just selected conveniently based on the people we come across.

EXPERIMENTS Experiments can reveal cause-and-effect relationships by allowing experimenters to observe whether a change in an independent variable affects some specific behavior, or dependent variable. In an experiment, the participants who receive a particular treatment constitute the experimental group; the participants who do not receive the treatment constitute the comparison group (control group).

EXPERIMENTS

INDEPENDENT VARIABLE It is a variable that stands alone and isn't changed by the other variables you are trying to measure. EX: someone's age might be an independent variable. Other factors like what they eat or how much they go to school or how much television they watch aren't going to change a person's age. You are looking for some kind of relationship between variables you are trying to see if the independent variable causes some kind of change in the other variables, or dependent variables. Question: What's a dependent variable?Answer: Just like an independent variable, a dependent variable is exactly what it sounds like. It is something that depends on other factors. For example, a test score could be a dependent variable because it could change depending on several factors such as how much you studied, how much sleep you got the night before you took the test, or even how hungry you were when you took it. Usually when you are looking for a relationship between two things you are trying to find out what makes the dependent variable change the way it does.Many people have trouble remembering which is the independent variable and which is the dependent variable. An easy way to remember is to insert the names of the two variables you are using in this sentence in they way that makes the most sense. Then you can figure out which is the independent variable and which is the dependent variable:(Independent variable) causes a change in (Dependent Variable) and it isn't possible that (Dependent Variable) could cause a change in (Independent Variable).For example:(Time Spent Studying) causes a change in (Test Score) and it isn't possible that (Test Score) could cause a change in (Time Spent Studying).We see that "Time Spent Studying" must be the independent variable and "Test Scoreent variable is exactly what " must be the dependent variable because the sentence doesn't make sense the other way around.

DEPENDENT VARIABLE An Example of a Dependent Variable in an Experiment Might Be: Blood Type Gender Eye Color Level of Depression Level of Depression is answer. Just like an independent variable, a dependent variable is exactly what it sounds like. It is something that depends on other factors. For example, a test score could be a dependent variable because it could change depending on several factors such as how much you studied, how much sleep you got the night before you took the test, or even how hungry you were when you took it. Usually when you are looking for a relationship between two things you are trying to find out what makes the dependent variable change the way it does

INDEPENDENT VS. DEPENDENT Many people have trouble remembering which is the independent variable and which is the dependent variable. (Independent variable) causes a change in (Dependent Variable) and it isn't possible that (Dependent Variable) could cause a change in (Independent Variable). EX: (Time Spent Studying) causes a change in (Test Score) and it isn't possible that (Test Score) could cause a change in (Time Spent Studying). It doesn't make sense the other way around. Many people have trouble remembering which is the independent variable and which is the dependent variable. An easy way to remember is to insert the names of the two variables you are using in this sentence in they way that makes the most sense. Then you can figure out which is the independent variable and which is the dependent variable:(Independent variable) causes a change in (Dependent Variable) and it isn't possible that (Dependent Variable) could cause a change in (Independent Variable).For example:(Time Spent Studying) causes a change in (Test Score) and it isn't possible that (Test Score) could cause a change in (Time Spent Studying).We see that "Time Spent Studying" must be the independent variable and "Test Scores variable is exactly what " must be the dependent variable because the sentence doesn't make sense the other way around.

ADDITIONAL EXAMPLE A group of college students were given a short course in speed-reading. The instructor was curious if a monetary incentive would influence performance on a reading test taken at the end of the course.  Half the students were offered $5 for obtaining a certain level of performance on the test, the other half were not offered money.  Independent variable:  Monetary incentive ($5 or no money)   Dependent variable:  Performance on reading test Experimental group:  $5 group (receive monetary incentive) Control group:  $0 group (no monetary incentive)

ADDITIONAL EXAMPLE A social psychologist thinks that people are more likely to conform to a large crowd than to a single person.  To test this hypothesis, the social psychologist had either one person or five persons stand on a busy walking path on campus and look up.  The psychologist stood nearby and counted the number of people passing by who also looked up. Independent variable:  Size of group (5 people or 1 person)   Dependent variable:  Conformity (measured by number of people looking up) Experimental group:  People passing 5 person group Control group:  People passing single person.  (This group gets “less” of the independent variable)

ADDITIONAL EXAMPLE To test a new voice feature in a cockpit design a flight simulator was used.  The simulator was programmed to give visual readings of flight information, or to give visual and auditory (voice) readings of flight information.  All test pilots were put through a simulated emergency landing procedure, but were randomly assigned to the visual, or visual and auditory conditions.  Flight experts rated each pilot’s performance in the simulator on a scale of 1 (very poor) to 10 (excellent). Independent variable:  Presence or absence of auditory (voice) readings.  (All pilots received visual readings, so that is a constant variable.)   Dependent variable:  Ratings of pilots’ performance Experimental group:  Pilots in auditory readings condition (visual + auditory) Control group:  Pilots in visual reading only condition (no auditory)

Cautions and Challenges from Science Correlation and Causation Quantity and Quality Ethics

In cross-sectional research, groups of people who are different in age but similar in all other important ways are compared on the characteristic that is of interest to the researcher(s). One limitation of cross-sectional research is that it is always possible that some variable other than age differentiates the groups.

LONGITUDINAL STUDIES In longitudinal research, the same people are studied over a period of time. Longitudinal research is particularly useful in studying developmental trends that occur over a long age span.

COHORT A cohort is a group of people born within a few years of each other who tend to share certain historical events and cultural shifts. Members of each cohort are affected by the values, events, technologies, and culture of their era.

CROSS SEC. / LONGITUDINAL Both longitudinal and cross-sectional researchers must bear in mind that research on a cohort may not be valid for people developing in an earlier or later cohort.

Cross-sectional studies confound age and cohort effects, so these results look more pessimistic than necessary. Longitudinal studies confound age and historical time, so you can’t tease out a number of differences related to subjects’ age between testing times. The cross-sectional study makes older folks look less intelligent; but those people were educated in a different era.

Cross-sequential study will analyze data three ways: First, it will compare groups of the same ages studied at different times; any differences over time between groups who are the same age are probably cohort effects. The second analysis compares people within a group, as they get older; any differences are the result of time (not only age). The third analysis compares differences between the same people as they grow older, but after the cohort effects are taken into account (from the first analysis). Any remaining differences are almost certainly the result of age. You can find the cohort effects by following the diagonals. This is the most time-consuming and complex of research designs, but it yields the best information.

IDENTIFY PITFALLS To identify possible pitfalls in the scientific method, and to summarize some of the ethical issues involved in conducting research with human participants. Correlation Quantitative vs. Qualitative IRB

CORRELATION Correlation is a number indicating the degree of relationship between two variables. A correlation is positive if both variables tend to increase together or decrease together, negative if one variable tends to increase when the other decreases, and zero if no connection is evident. Correlation does not prove causality.

CAUTION A correlation indicates that only two variables are related, not that one variable causes the other to occur. For instance, there is a correlation between immigrants in the United States (when compared with native-born in the same ethnic group) and having fewer low-birthweight babies. But the status of “immigrant” alone does not cause a woman to not have a low-birthweight baby. Always remember that correlation is not causation.

Quantitative vs. Qualitative Because numbers can be easily summarized and compared, scientists often rely on data produced by quantitative research. This method may be particularly limiting when researchers describe child development. Also, many developmental researchers use qualitative research that asks open-ended questions.

Most institutions of higher education emphasize quantitative data. Sometimes scientists translate qualitative research into quantifiable data; sometimes they use qualitative studies to suggest hypotheses for quantifiable research.

IRB When studying people, scientists take special care to ensure that participation is voluntary and harmless and that the study’s benefits outweigh its costs. They do this by establishing a code of ethics (set of moral and specific guidelines) for researchers to follow, which is enforced by the Institutional Review Board (IRB) at most educational and medical institutions. IRB – group that exists within most educational and medical institutions whose purpose is to ensure that research follows established guidelines and remains ethical.