Abstract:

Navigation can be classified into piloting and path integration based on the types of information used. Piloting allows navigators to use direction sensory cues regarding the environment and landmarks, but in path integration, navigators rely on self-motion information. Previous research has revealed that the presence of landmarks might influence human path integration, but it remains unclear how this process might be influenced by the participants’ knowledge about which target location to which they would be asked to return. Here, we report a study designed to investigate the effect of target knowledge in human path integration.
In the present study, we used Head-Mounted-Display Virtual Reality to present hallway-mazes, and employed a modified return-to-origin task used by Wan, Wang, and Crowell (2012). That is, the participants first traveled along 5-segment pathways where 0, 1, or 2 landmarks were present at the intersections. When arriving at the end of the outbound pathways, they were asked to return directly to the origin or one of the landmark locations. In order to manipulate target knowledge, we gave different instructions to three groups of participants at the beginning of each trail: the first group was not given any information about where to return; the second group was told about whether they would be asked to return to the origin or one of the landmark locations (without knowing which landmark exactly); and the third group was told about which specific location they would be asked to return to.
The results showed the effects of target knowledge on both the return-to-origin and return-to-landmark responses. When attempting to return to the origin, the uninformed group showed longer RTs when there were two landmarks than when there was no landmark; whereas the other two groups showed no such patterns. For another, when attempting to return to the specified landmarks, the uninformed group showed greater position errors than the other two groups. That is to say, target knowledge might diminish interference from the presence or increase of the landmarks on the return-to-origin responses, and lead to more accurate return-to-landmark responses.
Taken together, these results revealed that more knowledge about where to return might facilitate human path integration. One possibility is that more knowledge about the target might allow the participants to use a more adaptive strategy to reduce their working memory load and to simplify the structure of the outbound paths they need to process. These findings highlight the influence of non-perceptual factors on human path integration, and they indicate that path integration in humans might be an adaptive and strategic process.

Key words: path integration, target knowledge, landmark, virtual reality, spatial navigation