Supra-individual consistencies in navigator-driven landmark placement for spatial learning

Landmarks are an essential part of human navigation. In most situations, landmarks used for navigation are available in the environment. However, landmarks can also be set up deliberately to facilitate future orientation. The question how such navigator-driven and individual landmark placement affects spatial learning and what strategies are used has rarely been examined. We addressed this question with two experiments. Participants explored virtual environments and placed landmarks with the aim of developing a mental map of the environment (measured by sketch mapping, Study 1) or to facilitate wayfinding (Study 2). Their performance was compared to participants who did not place landmarks. Landmarks were detrimental to sketch mapping (Study 1), and provided no significant advantage for wayfinding (Study 2). However, we found strong supra-individual consistencies of landmark placement strategies in both studies, implying a "wisdom of the crowd" for critical landmark locations.