Many societal problems, including land use issues, are complex integrated human-ecological challenges that require an understanding of social and natural world connections. This dissertation investigates how secondary students perceive the social and natural world dimensions of land use, how they might act to support sustainable land use, and how Kaplan and Kaplan's (2008) Reasonable Person Model can inform teaching approaches to prepare students for such complex decisions and action-taking. The dissertation argues that subject compartmentalization in high schools adversely impacts students' abilities to use and to integrate information from various subjects to make a land use decision. Nine secondary science and social studies teachers and their students (n=500) participated in a quasi-experiment using pre- and posttests with treatment and comparison groups to gauge students' requests for social versus natural world information to make land use decisions. Students' self-reported actions and knowledge of actions to support sustainable land use were also measured. Additional data included classroom observations, teacher logs and interviews, and 52 student interviews. Results indicated that students requested social world over natural world information and preferred to consult with social scientists and stakeholders over natural scientists. Results also suggested that experiencing an integrated curriculum increased students' requests for natural world information relevant to the land use decision. Interestingly, this effect occurred even among social studies students whose teachers reported putting scant emphasis on the natural world curriculum content. Moreover, the type of course in which students experienced the curriculum predicted student information use. Finally, students were found to have a limited repertoire of land use actions and knowledge of actions and generally reported undertaking and thinking of individual actions such as recycling or trash pick-up rather than collective actions or political, consumer, or information-sharing actions. The curriculum had only a limited impact on students' actions and knowledge of actions, possibly because teachers did not engage students in actions. The concluding chapter discusses these results in the context of the Reasonable Person Model. The model suggests that cognitive needs, including mental model building, exploration, and meaningful participation, are mutually reinforcing and when provided for can enhance student learning outcomes.