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Part I. Chapter One. Introduction. 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
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Part I Chapter One Introduction 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 • 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.
Differential Sensitivity • Certain genes increase or decrease the likeihood that a child will be affected by the environment. • EX: MAOA gene
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
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.
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
Including All Kinds of People • Difference Equals Deficit Error • Sex Differences • Culture, Ethnicity, And Race • Socioeconomic Status • Finding the Balance
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
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.
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.
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.
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.
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.
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
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).
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.
DEPENDENT VARIABLE • An Example of a Dependent Variable in an Experiment Might Be: • Blood Type • Gender • Eye Color • Level of Depression
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.
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.
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.
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).
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.
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.
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.
