Christopher Peterson and Martin Seligman are psychologists who’ve done research concerning the underlying virtues of societies and cultures. Their conclusion was that there are several key virtues that every culture recognizes. The problem that many observers will notice is that the cultures’ attempt to display or act out these virtues may be misplaced, which often results in the ethical relativist’s denial of objective ethics.
The research can be found in their book Character Strengths and Virtues as well as several other papers they’ve published. This may serve as a defeater for the Dependency Thesis: What is right and wrong differs from one culture, society, religion, and time period to another. This is also a potential defeater for the Diversity/Plurality Thesis: What is right and wrong depends on the specific goals, needs, wants, beliefs, and historical context of a culture [no common method of inquiry].