Ethical aspects in engineering design have become increasingly important in recent years. A typical example is the recent rise of artificial intelligence ethics. This paper applies user studies of a design support tool to empirically verify that our ethical framework improves the creativity of an engineer’s design activity. The design support tool provides an environment for the promotion of ethical design perspectives and description. The experiments focus on two functionalities: semi-automatic generation and scenario path recommendation. These functions are designed around (...) the application of ethical design theory, which extends the hierarchical representation of artifacts. Doing this enables users to reconsider their themes at the highest level of the hierarchy and to apply a wider conceptual space of design solutions. For example, by reconsidering the positions of their research themes in the space of the representation field, users can semi-automatically edit them and identify focal areas. Using the scenario path recommendation, designers can update their research themes after considering the ethical impacts of those themes on stakeholders. Both functions are realized by exploiting a knowledge base of ethical and technological discourses. Finally, the ethical design theory is updated based on some unexpected results of our user studies with regards to the cyclic relationship among theory, tools, and observed data. For example, temporal dimensional aspects were confirmed as important. (shrink)