1. Ways of appropriating interior visual space

It is the visual system, eye and brain, impressed and informed by light, that enables us to perceive space. This perception results from the analysis and comparison (with each other and with memorized situations) of a series of fixations, 5 to 10 per second, providing stable images in the back of the eye. For each of these images, only a small part can be finely analyzed (about 1˚ of angle around the visual axis). In total, a central field of 10 to 20˚ can thus be analyzed without moving the head. The rest of the visual field can only be recognized if it has been previously analyzed for different gaze and head positions. At any given moment, the visual system must therefore adapt to the amount of light it receives, the nature of that light, and assess the distances and positions of perceived images.

Faced with a new situation, the individual constructs an initial...