Perception of Spatial Relationships in Impossible Spaces

Impossible spaces have been used to increase the amount of virtual space available for real walking within a constrained physical space. In this technique, multiple virtual rooms are allowed to occupy overlapping portions of the physical space, in a way which is not possible in real euclidean space. Prior work has explored detection thresholds for impossible spaces, however very little work has considered other aspects of how impossible spaces alter participants’ perception of spatial relationships within virtual environments. In this paper, we present a within-subjects study (n = 30) investigating how impossible spaces altered participants perceptions of the location of objects placed in different rooms. Participants explored three layouts with varying amounts of overlap between rooms and then pointed in the direction of various objects they had been tasked to locate. Significantly more error was observed when pointing at objects in overlapping spaces as compared to the non-overlapping layout. Further analysis suggests that participants pointed towards where objects would be located in the non-overlapping layout, regardless of how much overlap was present. This suggests that, when participants are not aware that any manipulation is present, they automatically adapt their representation of the spaces based on judgments of relative size and visible constraints on the size of the whole system.