In this qualitative case study we examined the impact of a specially-designed classroom intervention for a group of 15-16-year-old Dutch biology students' use of values in contemplating five socioscientific issues in the human-nature context. The students worked in small groups to support various aspects of their morality. An ethical matrix was used as a heuristic to explore different arguments and moral values from different perspectives. The collected data consisted of written assignments, group conversations, and individual interviews. The results show that students' use of values differed from one issue to another. The values they used in their moral decision-making indicated that the influence of the intervention activities, aimed at enhancing a relationship between moral agent (student) and moral object (topic), was limited. The study provides evidence that the intervention positively conduced to students' cognition of the values that are personally relevant. Recommendations for further theorization, research and practice are discussed.