fifth-, and seventh-grade children. The children are followed up 2 years later: the first graders are in third grade, the third graders are now in fifth grade, and the fifth graders are in seventh grade (assume the seventh graders graduated elementary school and have left the study). A new group of first-grade children are introduced to the study. Two years later, the first graders are in third grade, the third graders are in fifth grade, the fifth graders are in seventh grade, the seventh graders have aged out of the study, a new group of first-grade children are introduced to the study, and so on (Figure 1.6).
Figure 1.6 Cross-Sequential Research Design
The cross-sequential design provides information about age, cohort, and age-related change. The cross-sectional data (comparisons of first through seventh graders during a given year) permit comparisons across age-groups. But, as we have seen, these cross-sectional comparisons may reflect cohort effects rather than developmental differences. The longitudinal data (annual follow-up of participants in Grades 1 through 7) allow researchers to examine age-changes; that is, how the group of first graders develop throughout elementary school. However, studying only one cohort can also be misleading. A cross-sequential design helps developmental scientists separate cohort effects from age-related change. Because several cohorts are examined at once and over time, researchers can determine the effect of cohort. The sequential design is complex, but it permits developmental scientists to effectively answer questions about development.
Table 1.5
In summary, scientists use the scientific method to systematically ask and seek answers to questions about human development. Researchers’ decisions about measures and research designs influence the information that they collect and the conclusions that they make about development. Researchers have responsibilities to conduct sound research and also to adhere to standards of ethical conduct in research, as the next section describes. See Table 1.5 for a comparison of research designs.
Research Ethics
Researchers have responsibilities to conduct research that is scientifically sound. They are also obligated to adhere to standards of ethical conduct in research. Suppose a researcher wanted to determine the effects of malnutrition on development or the effects of bullying on emotional development. Would it be possible to design a study in which some children are exposed to bullying or some kindergarteners are deprived of food? Of course not. These studies violate the basic ethical principles that guide developmental scientists’ work: (1) beneficence and nonmaleficence, (2) responsibility, (3) integrity, (4) justice, and (5) respect for autonomy (American Psychological Association, 2010).
Beneficence and nonmaleficence are the dual responsibilities to do good and to avoid doing harm. Researchers must protect and help the individuals, families, and communities with which they work by maximizing the benefits and minimizing the potential harms of their work. Above all, participating in research must never pose threats to children beyond those they might encounter in everyday life. Researchers also have the responsibility to help participants. For example, when interviewing children about their experiences with violence in their community, a developmental scientist pays attention to their participants’ demeanor. If adolescents show distress in response to a particular set of questions, the scientist might direct, or even accompany, the participant to a therapist or mental health professional who can help him or her manage the distress.
The ethical principle of responsibility requires that researchers act responsibly by adhering to professional standards of conduct and clarifying their obligations and roles to others. For example, a researcher conducting interviews with children and parents must clarify her role as scientist and not counselor and help her participants understand that she is simply gathering information from them rather than conducting therapy. Researchers’ responsibility extends beyond their participants to society at large to ensure that their research findings are accurately portrayed in the media. The principle of responsibility means that researchers must attempt to foresee ways in which their results may be misinterpreted and correct any misinterpretations that occur (Lilienfeld, 2002; Society for Research in Child Development, 2007).
The principle of integrity requires that scientists be accurate, honest, and truthful in their work. Researchers should be mindful of the promises they make to participants and make every effort to keep their promises to the people and communities with which they work. In addition, the risks and benefits of research participation must be spread equitably across individuals and groups. This is the principle of justice. Scientists must take care to ensure that all people have access to the contributions and benefits of research. For example, when a study testing an intervention finds that it is successful, the participants who did not receive it (those who were in the control group) must be given the opportunity to benefit from the intervention.
Perhaps the most important principle of research ethics is respect for autonomy. Scientists have a special obligation to respect participants’ autonomy, their ability to make and implement decisions. Ethical codes of conduct require that researchers protect participants’ autonomy by obtaining informed consent—participants’ informed, rational, and voluntary agreement to participate. Soliciting informed consent requires providing the individuals under study information about the research study, answering questions, and ensuring that they understand that they are free to decide not to participate in the research study and that they will not be penalized if they refuse.
Respecting people’s autonomy also means protecting those who are not capable of making judgments and asserting themselves. Parents provide parental permission for their minor children to participate because researchers (and lawmakers) assume that minors are not able to meet the rational criteria of informed consent. Although children cannot provide informed consent, researchers respect their growing capacities for decision making in ways that are appropriate to their age by seeking child assent, children’s agreement to participate (Tait & Geisser, 2017). For a toddler or young child, obtaining assent may involve simply asking if he or she wants to play with the researcher (Brown, Harvey, Griffith, Arnold, & Halgin, 2017b). With increasing cognitive and social development, children are better able to understand the nature of science and engage meaningfully in decisions about research participation. In short, discussions about research participation should be tailored to children’s development, including offering more detailed information and seeking more comprehensive assent as children grow older (Roth-Cline & Nelson, 2013). Moreover, seeking assent helps children learn how to make decisions and participate in decision making within safe contexts (Oulton et al., 2016).
Developmental science is a broad field of study that integrates theory and research from many disciplines to describe, predict, and explain how children grow and change. Developmental scientists apply their knowledge to identify, prevent, and solve problems and to improve opportunities for individuals, families, and communities. Throughout this book, you will learn the fundamentals of child development, including physical, cognitive, and socioemotional change, as well as the implications of developmental science for social issues. We begin our journey in Chapter 2 by considering the role of genetics and environment in shaping child development.
Thinking in Context 1.4
Lua is interested in understanding academic achievement in elementary school students. Specifically, she believes that too much screen time harms students’ achievement.
1 How might Lua gather information to address her hypothesis?
2 What kind of research design should Lua use? What are the advantages and disadvantages of this design?
3 What are some of the challenges of measuring behaviors such as