Perceiving Shared Visual Space

The sharing of visual space is critical to much of human behavior.  Consider how normal face-to-face communication often relies on shared visual space, such as when one person looks at or points to an object or location in the environment with the purpose of informing another person the focus of his/her attention.  Shared visual space is also relevant in quite a different situation--a person often needs to judge what parts of the environment can be seen by another person.  Even more challenging is the situation where person A must assess what parts of space are visible to another person B, known to be present but hidden from view.  Here, there are no visibly specified vantage points, and instead A must deduce from the known or assumed three-dimensional geometry of the environment all possible vantage points that might be assumed by B in the occluded portions of the environment.