on measures of research comprehension, but some suggest caution about other dimensions of adolescents’ understanding and judgment.7

Children Compared to Adolescents A few studies suggest that children as young as age 6 or 7 years can comprehend some aspects of research. One study that included 6- to 9-year-olds (studied in groups not individually) concluded that although older children comprehended more about a vaccine study, children as young as 6 years could ask what the investigators viewed as reasonable questions about the research (Lewis et al., 1978). They could comprehend certain basic information about what might happen to them in medical treatment or research and what they were expected to do. A study by Susman and colleagues (1992) of hospitalized young people ages 7 to 20 years did not find important differences between children ages 7 to 13 years and young people ages 14 to 20 years. Both groups did better in understanding concrete features of research (e.g., what they were to do) than in comprehending more abstract features (e.g., alternatives and the right to withdraw). The investigators concluded that emotional factors (e.g., anxiety and a sense of control) were more important than age or cognitive development in affecting the participants’ understanding of research participation (Dorn et al., 1995).

Most studies, however, have reported differences in comprehension between younger and older children. For example, in assessing the results of a study of 102 children 7 to 18 years of age, Tait and colleagues (2003b) concluded that children under age 11 years had particularly limited understanding of the study protocol (which involved an anesthesia or a surgery study), the potential benefits, and their right to withdraw from the study. Another study (Nannis, 1991) reported that more than 84 percent of the fifth graders (approximately 11 years old) in the study correctly understood what research was, whereas only 35 percent of the third graders (approximately 9 years old) answered the question correctly. In a study that included only second, fourth, and sixth graders, Hurley and Underwood (2002) reported that few of the participants in their psychological study understood its primary goals, even after a debriefing. They speculate that their results may have reflected the complexity of both the study (which investigated how children coped with peer provocation) and the debriefing.

Broome and colleagues (2001) found that children younger than age 10


Some studies of decision making in a legal context have similar conclusions. For example, Bartholomew (1996) concluded that research shows similar decision-making capacities for adults and adolescents over the age of 14, but performance is more variable for younger individuals (see also Ambuel and Rappaport, 1992 and Scott et al., 1995).

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