- Bodo Herzog: Economics Department, ESB Business School, Reutlingen University, 72762 Reutlingen, Germany. ORCID
- Stefanie Schnee: Economics Department, ESB Business School, Reutlingen University, 72762 Reutlingen, Germany.
Rational behavior is a standard assumption in science. Indeed, rationality is required for environmental action towards net-zero emissions or public health interventions during the SARS-CoV-2 pandemic. Yet, little is known about the elements of rationality. This paper explores a dualism of rationality comprised of optimality and consistency. By designing a new guessing game, we experimentally uncover and disentangle two building blocks of Human rationality: the notions of optimality and consistency. We find evidence that rationality is largely associated to optimality and weakly to consistency. Remarkably, under uncertainty, rationality gradually shifts to a heuristic notion. Our findings provide insights to better understand Human decision making.