Does path integration contribute to human navigation in large-scale space?

Path integration is a process in which navigators estimate their position and orientation relative to a known location by using body-based internal sensory cues that arise from navigation-related bodily motion (e.g., vestibular and proprioceptive signals). Although humans are capable of navigating via path integration in small-scale space, a question has been raised as to whether path integration plays any role in human navigation in large-scale space because it is inherently prone to accumulating error. In this review, we examined whether there is evidence that path integration contributes to large-scale human navigation. It was found that navigation with path integration (e.g., walking in a large-scale environment) can enhance learning of the layout of the environment as compared with mere exposure to the environment without path integration (e.g., viewing a walk-through video while sitting), suggesting that the body-based cues are reliably processed and encoded through path integration when they are present during navigation. This facilitatory effect is clearer when proprioceptive cues are available than when the navigators receive vestibular cues only (e.g., driving or being pushed in a wheelchair). More specifically, path integration with proprioceptive cues may help build survey knowledge of the environment in which metric distance and direction between landmarks are represented. Overall, the existing data are indicative of path integration's contributions to large-scale navigation. This suggests that instead of dismissing it as too error-prone, path integration should be characterised as a fundamental mechanism of human navigation irrespective of the scale of a space in which it is carried out.