Grounding the Human Sciences: A Cross-Species Framework for Experimental Robustness

Human research typically examines human phenomena without first clarifying the roots of the capacities that underlie them. As a result, researchers often move directly from partial observations to narrative accounts or loosely defined constructs that lack clear boundaries and stable empirical targets, making them difficult to falsify. This contributes to unstable findings and persistent replication failures. Yet decades of research in primatology and comparative cognition show that many capacities studied in the human sciences have functionally comparable counterparts in other primates. These comparisons reveal the shared biological and cognitive foundations of human capacities and provide an empirical basis for evaluating whether theories characterize them correctly. Here, we propose a cross-species framework that aligns major domains of human cognition with functionally comparable capacities observed across species. We also introduce a cross-species workflow for producing robust results by grounding human research in comparative evidence. Together, the framework and workflow ground the human sciences in observable capacities and comparative evidence, moving beyond loosely defined constructs and narrative interpretations toward a robust, mechanism-based science.