Wednesday January 29 2014 Developmental 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 1 Wednesday January 29 2014 unbiased interpretations by the researcher may be difficult to obtain Meta analysis permits investigators to analyze the results of a large body of published conclusions about behavior research to draw general 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 the dependent variable on 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 2 Wednesday January 29 2014 Because of this circumstance researchers conducting quasiexperiments 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 p eri o d of t i m e u s ual l y sh o rter 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 3 Wednesday January 29 2014 Researchers 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 researchers to observe the electrical activity of the brain ERPs or the rate of blood flow through different brain regions fMRI ERPs offer timed information about the brain s response to outside stimuli fMRIs provide information about which brain regions are involved in processing particular kinds of events These procedures allow us to observe changes in the structure and function of the brain with age and to identify brain processes and structures that distinguish typical and atypical development Ethical Issues in Developmental Research Participants in research must be asked to provide informed consent given the chance to decline participation be debriefed