Abstract
Visual perception plays a central role in guiding navigation through the environment. Many previous studies have investigated how visual features of scenes (e.g., landmarks) influence navigation. In this study we take a different approach, asking how navigational experience with a scene affects behavioral and neural responses to the scene. We used virtual reality (VR) software to manipulate navigational experience while holding constant the visual properties of scenes. Participants navigated through VR outdoor environments, and performed a simple object detection task at a particular scene location. In half of the environments (navigable environments), participants could continue walking through the scene after performing the task. However, in the other half of the environments (non-navigable), participants could not continue forward, as if an invisible wall blocked navigation even though the scene was visually navigable. Assignment of visual environments to navigable and non-navigable conditions was counterbalanced across participants, so that the environments were the same in both conditions. In Experiment 1, participants experienced navigable and non-navigable environments and then performed a task in which they judged whether two scenes were visually the same or different. “Different” decisions were significantly slower when the scenes matched on navigability, than when the scenes differed in navigability. The effect remained significant even after regressing out visual similarities between scene pairs. Experiment 2 examined the effects of navigation experience on neural representations of scenes. Using slow-event related fMRI, we found that the multi-voxel pattern of the parahippocampal place area (PPA) distinguished visually identical scenes based on prior navigational experience. These results suggest that the PPA represents information about navigability obtained through prior experience, beyond those computable from the visual properties of the scene. This modulation of visual perception by prior navigational experience may help us construct a functionally meaningful visual environment.