Wednesday, January 29, 2014Developmental Psychology Chapter 2 Studying Child Development -Research Methods in Developmental Psychology •Like other scientists, developmental psychologists are concerned with using sound methodologies to glean information about children. The scientific method is used not only to test theories but also to gather information that can have applications in the lives of children. Researchers need to be concerned with operationally defending the variables in the study. That is, the variables must be specified in measurable terms. Variables must be valid; that is, they must actually measure the concept under consideration. Variables must also be reliable; that is, they must be obtained consistently from one time to another or from one observer to another. •Naturalistic observations involve the systematic recording of behaviors as they occur in children’s everyday environments. Two special concerns in this approach are participant reactivity, the chance that children will react to the presence of an observer by behaving in atypical ways, and observer bias, the possibility that the researcher will interpret observations to be consistent with his or her hypotheses. •Structured observations, usually conducted in the laboratory, allow the experimenter more control over situations that accompany children’s behaviors. Researchers can measure children’s overt behaviors or obtain physiological measures, such as heart rate or brain wave activity. One limitation of this approach is that children may not act as they would in a natural context. •Researchers can employ structured interviews or questionnaires if they are interested in children’s own reports of what they know or how they behave. Researchers need to be aware that children may not always answer questions truthfully and that systematic comparisons and 1Wednesday, January 29, 2014unbiased interpretations by the researcher may be difficult to obtain. •Meta-analysis permits investigators to analyze the results of a large body of published research to draw general conclusions about behavior. •In correlational studies, the investigator attempts to see whether changes in one variable are accompanied by changes in another variable. Researchers may observe a positive correlation, in which increases in one variable are accompanied by increases in another, or a negative correlation, in which increases in one variable are accompanied by decreases in the other. •The statistic used to assess the degree of relationship is the correlation coefficient (r). A related approach is regression analysis, in which researchers attempt to predict outcomes based on one or more predictor variables. One caution about these designs is that cause-and-effect conclusions cannot be drawn. •In the experimental design, the researcher manipulates one or more independent variables to see if they have an effect on the dependent variable. •Random assignment of participants to different treatment groups helps ensure that only the independent variable varies from one group to the other. Therefore, cause and effect relationships among variables can be identified. •Studies in which control procedures permit strong statements about cause and effect are said to have high internal validity. The concept of external validity refers to the ability to generalize a study’s findings to other situations, contexts, or populations. Variations on the experimental technique are field experiments, in which the experimental manipulations are carried out in a natural setting, and quasi-experiments, in which the assignment of participants to experimental groups is determined by the participants’ natural experiences. 2Wednesday, January 29, 2014•Because of this circumstance, researchers conducting quasi-experiments must be concerned with ruling out alternative explanations for their findings. •In case-studies or the single-case design, the researchers intensively studies one or a few individuals over a period of time. The former usually involves a detailed narrative description, whereas the latter involves the systematic collection of data. The ability to generalize to a larger population may be limited with these approaches. -Special Issues in Developmental Research •Longitudinal studies test the same participants repeatedly over an extended period of time. This approach requires a significant investment of time, may involve attrition of participants, and could be vulnerable to the age-history confound. It is the only method that allows researchers to examine the stability of traits •Cross-sectional studies examine participants of different ages at the same time. Although this approach requires less time and fewer resources than the longitudinal approach, it is vulnerable to cohort effects. •Sequential studies examine children of two or more ages over period of time, usually shorter than that used in longitudinal studies. This approach combines the advantages of the cross-sectional and longitudinal approaches but is also vulnerable to the problems associated with each. •Microgenetic studies require the close observation of children as they perform some task, in order to identify the specific processes that change with development. They require careful planning and the selection of tasks that will reveal developmental change, as well as intensive efforts at observation. •Cross-cultural studies, which compare individuals from different cultural groups, can be especially helpful in answering questions about universals in development. 3Wednesday, January 29, 2014Researchers must make sure that tasks are comparable across cultural groups, however. •An important methodological tool, especially for those who wish to learn about the meaning systems within a culture, is ethnography, the use of observations and interviews by a researcher who acts as a participant-observer. •New technologies in neuroscience allow