Lifespan Development. Tara L. Kuther

      The sequential design provides information about age, cohort, and age-related change. The cross-sectional data (comparisons of 12-, 14-, 16-, and 18-year-olds from a given year) permit comparisons among age groups. The longitudinal data (annual follow-up of participants ages 12 through 18) permit helps scientists separate cohort effects from age-related change. Because several cohorts are examined at once, the effect of cohort can be studied. The sequential design is complex, but it permits human development researchers to disentangle the effects of age and cohort, as well as answer questions about developmental change.

      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 1.8 for a comparison of research designs.

      Thinking in Context 1.4

      Dorothy is interested in understanding smoking in middle school students. Specifically, she believes that low self-esteem causes students to smoke.

      1 How might Dorothy gather information to address her hypothesis?

      2 What kind of research design should Dorothy use? What are the advantages and disadvantages of this design?

      3 What are some of the challenges of measuring behaviors such as smoking and internal characteristics such as self-esteem?

      4 How can her study be improved to overcome the weaknesses you have identified?

      Research Ethics

      Suppose a researcher wanted to determine the effects of an illegal drug on pregnant women or the effects of malnutrition on kindergarteners. Would it be possible to design a study in which certain pregnant women were assigned to ingest the illegal drug? Or one in which certain kindergarteners were deprived of food? 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. Sometimes, though, researchers’ desire to answer questions and solve problems may conflict with the need to protect the participants in research studies. For example, suppose a researcher studying adolescents learns that a participant is in jeopardy, whether engaging in health-compromising behaviors (e.g., cigarette smoking, unsafe driving, or unhealthy behavior), contemplating suicide, or engaging in illegal or harmful activities (e.g., drug addiction, stealing, or violence). Is the researcher responsible for helping the adolescent? If the researcher is studying a behavior that correlates with health-compromising behaviors, she might anticipate encountering participants who are in jeopardy. Researchers who study risky behaviors expect to encounter participants who engage in potentially dangerous activities. Helping the adolescent might involve removing him or her from the study and potentially compromising the study. In addition, adolescents generally expect that researchers will maintain confidentiality; violating their confidentiality may be harmful. Although current ethical guidelines address researchers’ obligations to help and not harm, they leave a certain amount of judgment to the researcher regarding how to help and not harm participants and the conflicting duties to maintain confidentiality and disclose participant problems (Hiriscau, Stingelin-Giles, Stadler, Schmeck, & Reiter-Theil, 2014; Sharkey, Reed, & Felix, 2017).

      A second principle that guides developmental scientists’ work is that they must act responsibly by adhering to professional standards of conduct, clarifying their obligations and roles to others, and avoiding conflicts of interest. For example, a psychologist who conducts research 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 are responsible not only to their participants but also to society at large. In reporting results, researchers should be mindful of the social and political implications of their work (Society for Research in Child Development, 2007). Researchers must consider how their findings will be portrayed in the media, attempt to foresee ways in which their results may be misinterpreted, and correct any misinterpretations that occur. For example, one highly publicized study compiled the existing research literature examining college students who had become sexually involved with an adult prior to reaching the legal age of consent (Rind, Tromovitch, & Bauserman, 1998). After compiling the results of many research studies, the scientists determined that young people’s coping and development varied depending on a number of factors within the individual, situation, and broader context; not all the young people appeared to be harmed, and those who were older when the relationship began often appeared well adjusted. These findings were misinterpreted by some organizations, media outlets, and politicians as suggesting that sexual involvement with minors was acceptable or even beneficial—clearly not the researchers’ conclusions (Garrison & Kobor, 2002).

      The principle of integrity requires that scientists be accurate, honest, and truthful in their work and make every effort to keep their promises to the people and communities with which they work. The principle of justice means that the benefits and risks of participation in research must be spread equitably across individuals and groups. Scientists must take care to ensure that all people have access to the contributions and benefits of research. For example, when research study suggests that an intervention 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 that scientists have a special obligation to respect participants’ autonomy, their ability to make and implement decisions. Ethical codes of conduct require that researchers obtain from all participants their informed consent—their informed, rational, and voluntary agreement to participate. Researchers must provide participants with information about the research study, answer questions, help them to make their own decisions about whether to participate in the study, and ensure 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.

      Table 1.9

      Sources: American Psychological Association (2010); Society for Research in Child Development (2007).

      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 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, 2017). 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 (Kuther, 2003; 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).

      Traumatic brain injury, dementia, mental illness, some physical illnesses, and advanced age can impair